Crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have revolutionized control of some major pests. Some recently introduced Bt crops make Vip3Aa, a vegetative insecticidal protein (Vip), which reportedly does not share binding sites or structural homology with the crystalline (Cry) proteins of Bt used widely in transgenic crops for more than two decades. Field-evolved resistance to Bt crops with practical consequences for pest control includes 21 cases that collectively reduce the efficacy of nine Cry proteins, but such practical resistance has not been reported yet for any Vip. Here, we review previously published data to evaluate cross-resistance between Vip and Cry toxins. We analyzed 31 cases based on 48 observations, with each case based on one to five observations assessing cross-resistance from pairwise comparisons between 21 resistant strains and 13 related susceptible strains of eight species of lepidopteran pests. Confirming results from previous analyses of smaller data sets, we found weak, statistically significant cross-resistance between Vip3 and Cry1 toxins, with a mean of 1.5-fold cross-resistance in 21 cases (range: 0.30–4.6-fold). Conversely, we did not detect significant positive cross-resistance between Vip3 toxins and Cry2Ab. Distinguishing between weak, significant cross-resistance, and no cross-resistance may be useful for better understanding mechanisms of resistance and effectively managing pest resistance to Bt crops.

Wild bees supply sufficient pollination in Cucurbita agroecosystems in certain settings; however, some growers continue to stock fields with managed pollinators due to uncertainties of temporal and spatial variation on pollination services supplied by wild bees. Here, we evaluate wild bee pollination activity in wholesale, commercial pumpkin fields over 3 yr. We identified 37 species of bees foraging in commercial pumpkin fields. Honey bees (Apis mellifera L. [Hymenoptera: Apidae]), squash bees (Eucera (Peponapis) Say, Dorchin [Hymenoptera: Apidae]), and bumble bees (Bombus spp., primarily B. impatiens Cresson [Hymenoptera: Apidae]) were the most active pollinator taxa, responsible for over 95% of all pollination visits. Preference for female flowers decreased as distance from field edge increased for several bee taxa. Visitation rates from one key pollinator was negatively affected by field size. Visitation rates for multiple taxa exhibited a curvilinear response as the growing season progressed and responded positively to increasing floral density. We synthesized existing literature to estimate minimum ‘pollination thresholds’ per taxa and determined that each of the most active pollinator taxa exceeded these thresholds independently. Under current conditions, renting honey bee hives may be superfluous in this system. These results can aid growers when executing pollination management strategies and further highlights the importance of monitoring and conserving wild pollinator populations.

Bumble bees (Bombus [Hymenoptera: Apidae]) are important pollinators for agricultural crops, which has led to their commercial domestication. Despite their importance, little is known about the reproductive biology of bumble bees native to North America.The Hunt bumble bee (Bombus huntii Greene [Hymenoptera: Apidae]) and the Vosnesensky bumble bee (Bombus vosnesenskii Radoszkowski [Hymenoptera: Apidae] are native candidates for commercial production in western North America due to their efficacy in providing commercial pollination services. Availability of pollinators native to the region in which services would be provided would minimize the likelihood of introducing exotic species and spreading novel disease. Some parasites are known to affect bumble bee reproduction, but little is known about their prevalence in North America or how they affect queen success. Only 38% of wild-caught B. huntii and 51% wild-caught B. vosnesenskii queens collected between 2015 and 2017 initiated nests in the laboratory. Our objective was to identify causal factors leading to a queen's inability to oviposit. To address this, we dissected each broodless queen and diagnosed diseases, assessed mating status, and characterized ovary development. Nematodes, arthropods, and microorganisms were detected in both species. Overall, 20% of queens were infected by parasites, with higher rates in B. vosnesenskii. Over 95% of both species were mated, and over 88% had developed ovaries.This suggests that parasitism and mating status were not primary causes of broodlessness. Although some failure to nest can be attributed to assessed factors, additional research is needed to fully understand the challenges presented by captive rearing.

A successful Integrated Pest Management approach to Varroa destructor Anderson and Trueman control in managed colonies of western honey bees Apis mellifera Linnaeus (Hymenoptera: Apidae) must be an improvement over conventional control methods and include cost-effective treatments that can be readily employed by beekeepers. Herein, we tested the efficacy of oxalic acid (OA) vaporization and brood interruption as Varroa controls. Sixty experimental colonies were randomly assigned to one of six treatment groups with 10 colonies per group.The six treatments were: 1) OA applied once, 2) OA applied three times, 3) brood interruption, 4) OA applied once + brood interruption, 5) OA applied three times + brood interruption, and 6) no OA or brood interruption. The OA was applied via vaporization, with each application being 1 g OA applied through the hive entrance (label rate), on the bottom board. Brood interruption was accomplished by caging a colony's queen in a queen cage for a period of 24 d. An additional 10 colonies were treated with amitraz (Apivar - positive control). Varroa levels were estimated before, during, and after treatment applications using sticky boards left in colonies for 3 d. Our data suggest that queen caging to achieve brood interruption during the fall season can negatively impact colony strength and survival. We observed high colony mortality in some treatments, despite diligent colony management to alleviate the side effects of the treatments. Colonies treated with amitraz were healthier and had better survival than those treated with OA vaporization. In conclusion, OA and/or brood interruption did not provide sufficient Varroa control.

Huanglongbing, a highly destructive disease of citrus species, is associated with a fastidious, gram-negative, phloem-limited bacteria (Candidatus Liberibacter spp.). In Florida, the causative agent of Huanglongbing (HLB) is C. Liberibacter asiaticus (CLas) and it is transmitted by the insect vector, Asian citrus psyllid (Diaphorina citri Kuwayama). Previous investigations have revealed systemic infection of CLas with an erratic and uneven distribution of pathogen in tree phloem. However, previous investigations did not consider the potential impact of plant vegetative growth on presence/absence of CLas in planta. Our objectives were to determine: 1) the effect of vegetative growth of Citrus sinensis (L.) Osbeck cv Valencia on detection of CLas in mature leaves, and 2) the impact of CLas inoculation frequency on progression of CLas titer in citrus leaves through the first year of infection. Temporal dynamics of CLas detection were associated with vegetative flush growth. Surprisingly, there was no difference in CLas titer detected between plants exposed to infected vectors for a one-time 7 d inoculation access period, as compared with plants exposed to continuously breeding CLas-infected insects over the course of an entire year of plant infection. Our results suggest that the CLas bacterium is transported through phloem during annual movement of carbon compounds needed for vegetative plant growth, including transportation from roots to mature leaves. These results highlight the importance of vegetative growth on temporal dynamics of CLas in citrus, and suggest a critical role of the sink-source interaction on presence/absence of CLas in leaves.

Cacopsylla picta (Förster, 1848) (Hemiptera: Pysllidae) is the main vector of apple proliferation, a phytoplasma-caused disease. It represents one of the most severe problems in apple orchards, and therefore, there is a mandatory requirement to chemically treat against this pest in the European Union. Sexual communication using substrate-borne vibrations was demonstrated in several psyllid species. Here, we report the characteristics of the vibrational signals emitted by C. picta during courtship behavior.The pair formation process can be divided into two main phases: identification and courtship. Females initiate the communication on the host plant by emitting trains of vibrational pulses and, during courtship, if males reply, by emitting a signal consisting of a series of pre-pulses and a ‘buzz’, a duet is established. Moreover, a scanning electron microscopy investigation showed the presence of a stridulatory structure on the thorax and wings of both sexes, whereas the video recordings elucidated associated wing movement.The results provide new information about the biology of this phytoplasma vector and could form a basis of an environmentally friendly pest management strategy.

Aster Yellows phytoplasma (AYp; Candidatus Phytoplasma asteris) is associated with diseases of herbaceous plants, including ornamentals and important commercial vegetable and grain crops. The aster leafhopper (ALH; Macrosteles quadrilineatus Forbes) is the predominant vector of these bacteria, though other leafhopper species can acquire and transmit AYp. Potentially inoculative leafhoppers are reported to overwinter in the southern United States and migrate to northern latitudes in the spring. Examining the genetic similarities and differences in AYp associated with southern and northern populations of ALH may provide insight into the role that migrating ALH play in AYp disease development. To investigate similarities among geographically distinct populations of ALH and characterize the variation in AYp associated within these populations, we identified genetic variations in subgroup designation and the relative proportions of secreted AY-WB proteins from field-collected populations of AYp isolated from ALH from select locations in the southern (Arkansas, Kansas, Oklahoma, and Texas) and the northern United States (Wisconsin) in 2016, 2017, and 2018. Isolated phytoplasma were tested for variation of AYp genotypes, numbers of potentially inoculative (AYp-positive) ALH, and presence of specific AYp virulence (effector) genes. Geographically distinct populations of ALH collected in northern and southern regions were similar in CO1 genotype but carried different proportions of AYp genotypes. While similar AYp strains were detected in geographically distinct locations, the proportion of each genotype varied over time.

Xylella fastidiosa (Wells) is a xylem-limited bacterium that causes Pierce's disease of grapevines. The bacterium is transmitted by insect vectors such as the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar). Experiments were conducted to compare the role of selected X. fastidiosa genes on 1) bacterial acquisition and retention in GWSS foreguts, and 2) transmission to grapevines by GWSS. Bacterial genotypes used were: mutants Xf-ΔpilG, Xf-ΔpilH, Xf-ΔgacA, and Xf-ΔpopP; plus wild type (WT) as control. Results showed that Xf-ΔpilG had enhanced colonization rate and larger numbers in GWSS compared with WT. Yet, Xf-ΔpilG exhibited the same transmission efficiency as WT. The Xf-ΔpilH exhibited poor acquisition and retention. Although initial adhesion, multiplication, and retention of Xf-ΔpilH in GWSS were almost eliminated compared with WT, the mutation did not reduce transmission success in grapevines. Overall, Xf-ΔgacA showed colonization rates and numbers in foreguts similar to WT. The Xf-ΔgacA mutation did not affect initial adhesion, multiplication, and long-term retention compared with WT, and was not significantly diminished in transmission efficiency. In contrast, numbers of Xf-ΔpopP were variable over time, displaying greatest fluctuation from highest to lowest levels. Thus, Xf-ΔpopP had a strong, negative effect on initial adhesion, but adhered and slowly multiplied in the foregut. Again, transmission was not diminished compared to WT. Despite reductions in acquisition and retention by GWSS, transmission efficiency of genotypes to grapevines was not affected. Therefore, in order to stop the spread of X. fastidiosa by GWSS using gene-level targets, complete disruption of bacterial colonization mechanisms is required.

Biological control offers a long-term and sustainable option for controlling the destructive forest pest emerald ash borer (EAB), Agrilus planipennis Fairmaire, in North America. Three larval parasitoids, Spathius agrili Yang (Hymenoptera: Braconidae), Tetrastichus planipennisi Yang (Eulophidae), and Spathius galinae Belokobylskij & Strazanac, have been introduced to North America from the native range of EAB (northeastern Asia). While T. planipennisi appears to be persisting where it has been introduced in northern United States, S. agrili failed to establish in northeastern states. The more recently identified parasitoid S. galinae was recovered from the Russian Far East and climate matching suggests it should be suited for release in colder climates. We collected data on the phenology of EAB and its introduced larval parasitoids from colonies established in an insectary, growth chambers, and field-caged trees in Syracuse, New York to determine whether asynchrony between parasitoids and EAB or climate could impact establishment and persistence. Phenological data indicated EAB has one and 2-yr life cycles in New York, with parasitoid-susceptible EAB larvae available spring to fall for parasitism. Insectary and growth chamber studies indicated S. galinae and T. planipennisi were synchronous with EAB phenology, and field studies suggested both species could overwinter in northeastern climates. Spathius agrili was asynchronous with EAB phenology and climate, emerging when fewer parasitoid-susceptible EAB larvae were available and temperatures were not optimal for survival. Our results suggest S. galinae and T. planipennisi are suited for biological control of EAB at the northern limits of its range in North America.

The effects of six average daily temperatures, 15, 20, 25, 30, 32, and 35°C, that were either constant or fluctuating over 24 h on development times of California-sourced Diaphorina citri Kuwayama nymphs were examined. Thermal performance curves for immature stages of D. citri were characterized using one linear and six nonlinear models (i.e., Ratkowsky, Lobry-Rosso-Flandrois, Lactin-2, Brière-2, Beta, and Performance-2). Daily thermal fluctuations had significant effects on development times of D. citri nymphs, which differed across experimental temperatures. Diaphorina citri nymphs reared at constant temperatures completed development faster than those reared under fluctuating profiles with equivalent temperature means. Linear model estimates of degree-days required for completion of cumulative development of D. citri were 25% lower for constant temperatures when compared with fluctuating temperature regimens. Nonlinear model estimations of optimum developmental temperature and upper theoretical temperature bounds for development were similar for individuals reared under constant and fluctuating temperatures. Nevertheless, the estimated values of lower theoretical temperature limits above which development occurred were lower under fluctuating than constant temperatures. A meta-analysis of published D. citri temperature-dependent development literature, synthesizing datasets of five globally distributed populations (Brazil, California, China, Florida, and Japan) reared under different constant temperatures on six different host plants (i.e., Citrus limonia, C. sinensis cv Natal, C. sinensis cv. Pêra, C. reticulata, Fortunella margarita, and Murraya paniculata), together with the results of this study (C. volkameriana), revealed convergence in estimates of developmental parameters.These results have implications for predicting D. citri invasion and establishment risk and subsequent population performance across various climactic gradients and geographic regions.

Trichogramma japonicum Ashmead (Hymenoptera: Trichogrammatidae) and Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) are important parasitoids of Lepidopteran pests and are used for biological control in rice fields. In this study, the response of two of these parasitoids to four insecticides (chlorpyrifos, chlorantraniliprole, emamectin benzoate, and spinosad) were evaluated at target sublethal concentrations (TSC₁₀ and TSC₂₅, representing the LC₁₀ and LC₂₅ to the target pest) of the important rice pest, Cnaphalocrocis medinalis (Guenée). Each of the insecticides led to the mortality of adult T. japonicum and T. dendrolimi at TSC₁₀ and TSC₂₅, whereas no significant differences in the mortality of T. japonicum between TSC₁₀ of chlorantraniliprole and control groups occurred. The parasitic capacity increased at F₀ of T. japonicum at the two TSCs of spinosad treated host eggs, whereas the TSC₁₀ was lower for emamectin benzoate at F₁ for T. japonicum. The TSCs of chlorpyrifos treated host eggs negatively influenced the emergence rates of T. japonicum at F₁. Emamectin benzoate with TSC₁₀ reduced the female ratio of T. japonicum at F₁. For T. dendrolimi, the TSCs of chlorpyrifos treated host eggs negatively influenced the emergence rates at F₁. These findings indicate that T. japonicum and T. dendrolimi are affected by insecticides at TSCs, and among the four insecticides, chlorantraniliprole had the lowest mortality rates for T. japonicum and T. dendrolimi at TSCs.

Heortia vitessoides Moore is the most serious insect defoliator of Aquilaria sinensis (Lour.) Gilg, an endangered and economically important plant that produces highly prized agarwood. Samples from recently identified indigenous natural populations of Trichogramma pintoiVoegele were collected from H. vitessoides eggs in A. sinensis forests inYunnan Province, China.To assess the potential capacity of this parasitoid for use as a biological control agent, its functional response, female reproductive potential, and male insemination capacity were investigated in this study. Females successfully parasitized 1- to 4-d-old eggs of H. vitessoides but failed to parasitize 5- to 8-d-old eggs.The parasitoid exhibited a Holling type II functional response, and the estimated maximum numbers of 1- to 4-d-old H. vitessoides eggs parasitized by a single T. pintoi female were 38.1, 29.8, 26.0, and 22.2 eggs over a 24-h period, respectively. Additionally, the parasitoid's average lifetime fecundity was 89.8 ± 2.5 eggs, of which 66.26% were laid within the first 2 d. The average number of total females that mated with a male in his lifetime (4.70 ± 0.13 d) was 10.4, and the average number of total daughters of a male was 292.1. On day 1 of male adult life, the greatest number of females were inseminated by males, and the most daughters were produced; however, the number of copulations and insemination ability decreased rapidly with male age.These results suggest that T. pintoi is a promising candidate for inundative release against H. vitessoides in China, and these findings will guide efforts in achieving mass production of this parasitoid.

The polyphagous moth, Thaumatotibia leucotreta (Meyrick) is among the major constraints to the horticultural industry in East Africa. In a search of sustainable control methods, the pathogenicity of the dry conidia of 17 Metarhizium anisopliae (Metschn.) and five Beauveria bassiana (Bals.) (Vuill.) isolates were tested against T. leucotreta moths. The conidial uptake by a single moth, horizontal transmission, and effect of fungal inoculant on egg-laying and hatchability for the pest were also assessed. The findings from this study showed that tested fungi were virulent to the moths, with 12 isolates causing mortality that ranged between 58.8 and 94.2% for M. anisopliae and three isolates between 57.6 and 84.6% for B. bassiana. The entomopathogenic fungi isolates, M. anisopliae ICIPE 69 and B. bassiana ICIPE 279 were highly virulent with low lethal times to 50% mortality (LT₅₀) of 3.81 and 5.13 d, respectively. The isolate, ICIPE 69 conidia acquisition by a single moth were approximately 4.58 × 10⁶ and 3.51 × 10⁶ for males and females, respectively. The lowest survival rate (3.33 %) caused by inoculum transmission was recorded in donor males compared to 16.67% in recipient males. Fecundity was reduced by 33.6 and 25.9% for donor and recipient females, respectively. The pest can acquire conidia from the treated substrate and transmission is then possible between adults. ICIPE 69 is virulent and reduces the reproduction potential of the pest after transmission. The findings are discussed in the prospects of microbial control of this pest using an autodissemination technique.

The pea leaf weevil, Sitona lineatus L., is an important pest of field peas and faba beans in most temperate regions. As no information is currently available on efficacy of biopesticides for S. lineatus control, laboratory bioassays were performed to evaluate the impact of biopesticides (spinosad, Beauveria bassiana strain GHA, pyrethrins, B. bassiana GHA + pyrethrins, and B. bassiana GHA + azadirachtin) against adults of this pest.The concentrations used in this bioassay were 0.1, 0.5, 1.0, and 2.0 times the lowest labeled application rate of each product. Results were further verified in cage experiments by assessing biopesticide effects on adult mortality and feeding damage in pea plants.The impact of biopesticides on mortality of larvae of two beneficial species, Chrysoperla carnea and Adalia bipunctata, was also tested in laboratory conditions. We found spinosad to be the most promising candidate, causing 100% adult mortality at high and medium concentrations. Beauveria bassiana and its combination with pyrethrins caused 60–62% adult mortality, but only at the highest concentration. In contrast, B. bassiana + azadirachtin and pyrethrins treatments caused only minimal adult mortality at all concentrations. In cage experiments, spinosad and B. bassiana + pyrethrins had significant effects on adult mortality and provided foliage protection from adult feeding. Conversely, the fungus treatment alone showed inconsistent performance. Beauveria bassiana and spinosad were generally harmless to C. carnea and A. bipunctata larvae, but B. bassiana + pyrethrins was toxic toward beneficial species.These results could help to improve integrated pest management programs intended to control S. lineatus.

Addressing the risk from pests present in wood and wood products destined for international trade is an essential step towards minimizing the movement, introduction and establishment of invasive species. One method of managing the pest risk associated with wood commodities is the use of a systems approach that incorporates multiple independent measures applied along a production pathway. However, quantifying the reduction of risk can be difficult because the approach requires raw material infested with the pest of interest at a sufficient density to be able to quantify changes in pest abundance. We tested a systems approach for the production of sawn wood using green ash, Fraxinus pennsylvanica Marshall (Lamiales: Oleaceae), infested with emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), by quantifying the change in pest density during the milling process and the precise effect of heat treatment on insects in situ. Greater than 90% of emerald ash borer were removed at the first step of the milling process (debarking) and >99% were removed before the production of green sawn wood. No insects survived kilning or heat treatment. All life stages of emerald ash borer were killed at 56°C and above. Heat, however, had no sublethal effect on emerald ash borer performance. These results show that the application of a systems approach to mitigate emerald ash borer in heat-treated, sawn wood is effective. Moreover, the model-system approach developed in this study can be a template for investigating the effect of systems approaches for other phloem-feeding insects.

Khapra beetle, Trogoderma granarium Everts, is unusual in two key respects. First, they are among the most cold hardy of stored-product insect pests even though they originate in hot and dry regions of the Indian subcontinent. Second, their larvae can enter into diapause to survive harsh environmental conditions. In the present study, we examined whether these two phenomena are related, i.e., due to cross-tolerance. Cross-tolerance is the tolerance to one ecological stress when induced by a separate stress. To investigate this, khapra beetle larvae were reared at different relative humidities (3, 28, 49, and 79%) in either nondiapausing or diapausing conditions. Then the cold tolerance of larvae was estimated by measuring mortality after different durations at –10°C. For nondiapausing larvae, relative humidity had little effect on cold tolerance with the lethal time to 50% mortality (LT₅₀) occurring between 2 and 4 d. For diapausing larvae, cold tolerance increased with greater desiccation stress with LT₅₀'s of 5, 7, 10, and 18 d at 79, 49, 28, and 3% RH, respectively. This suggests that the physiological mechanisms that protect diapausing larvae from desiccation may also increase cold tolerance, even though these insects may rarely be exposed to low temperatures.

A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is attracted to its male-produced aggregation pheromone, a ∼3.5:1 mixture of (3S,6S,7R,10S)- and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol (SSRS and RSRS respectively), and also to the pheromone of its Asian sympatric species Plautia stali Scott (Hemiptera: Pentatomidae), methyl (2E,4E,6Z)-2,4,6-decatrienoate (MDT). A stereoisomeric mixture of (7R) 10,11-epoxy-1-bisabolen-3-ols (= mixed murgantiols) is used together in commercialized products with MDT because the latter is a synergist for H. halys attraction to mixed murgantiols. However, the optimal ratio for MDT combination with mixed murgantiols, and the sensitivity of bug captures to variation in ratio of the two pheromone components, have not been tested to date. Using black pyramid traps at two sites (in Maryland and West Virginia, United States), different ratios of mixed murgantiols to MDT were tested over two entire seasons. Also, captures using various ratios of the two active pheromone stereoisomers were undertaken in month-long trials with and without MDT. Results showed that H. halys adult and nymphal captures were relatively insensitive to the ratio of synthetic pheromone (mixed murgantiols) to MDT, as long as each was present in the trap. Captures of adults and nymphs were responsive to the lure loading of the SSRS isomer, but relatively insensitive to levels of the minor component, RSRS.The relative insensitivity of H. halys to these attractant ratios gives flexibility to development of more cost-efficient synthesis and trapping as well as other semiochemical-based management tactics.

Between 1998 and 2017, we conducted studies in wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae), to elucidate the temporal dynamics of the blueberry maggot fly, Rhagoletis mendax Curran, and its parasitoid, Biosteres melleus (Gahan). A predictive model for the emergence of R. mendax was validated at two sites over 3 yr. A second predictive model for the major parasitoid, B. melleus, of R. mendax was constructed and suggests that the delay in emergence of the parasitoid relative to its host provides a period or ‘biological window’ of 9 d where insecticide sprays can be applied to manage R. mendax with a limited impact on the parasitoid. A 20-yr study on the parasitoid/host dynamics showed parasitism rates ranging from 0.5 to 28.2%. It appears that R. mendax populations in Maine wild blueberry are characterized by stable equilibrium dynamics, significantly affected by stochastic processes. There was a weak, but significant relationship between B. melleus density and R. mendax intrinsic rates of growth. Our data suggest that R. mendax population dynamics in wild blueberry is characterized by an unstable equilibrium tipping point of 7.9 maggots per liter of blueberries or an average of 10 flies per trap.

The redbacked cutworm, Euxoa ochrogaster (Guenée), and the pale western cutworm, Agrotis orthogonia (Morrison), are generalist pests that cause sporadic economic damage to several annual crops in the Canadian Prairies. Early larval instars feed on foliage, whereas mature larvae eat into the stem and sever crop seedlings. Here, we evaluate the influence of annual crop species and host fertilization on the larval performance and feeding preference of both cutworm species. Performance is the ability of an insect to reach its maximum growth potential. The first set of experiments evaluated larval development and preference on canola (Brassica napus L. [Capparales: Brassicaeae]), field peas (Pisum sativa L. [Fabales: Fabaceae]), and spring wheat (Triticum aestivum L. [Cyperales: Poaceae]).The redbacked cutworm had higher performance on canola and peas, while the pale western cutworm had higher performance on wheat. In multiple-choice feeding experiments, the redbacked cutworm consumed more canola, whereas the pale western cutworm consumed more spring wheat. The third set of experiments evaluated larval development on fertilized and unfertilized seedlings of canola and spring wheat seedlings. When fed unfertilized seedlings, the redbacked cutworm had better performance on canola than spring wheat, whereas pale western cutworm had better performance on spring wheat than canola. Fertilizer application enhanced the performance of both cutworms regardless of the crop species. Despite their generalist feeding behavior, both cutworm species have a larval feeding preference for the host plant on which they achieve high performance. Canola-cereal cropping is a common crop rotation schedule in the region; however, this tactic will not negatively impact cutworm performance.

The black soldier fly (BSF, Hermetia illucens (Linnaeus), Diptera: Stratiomyidae) is an edible insect widely reared by using various types of organic wastes as its diet. Developing tools to evaluate the growth performance of BSF is crucial for improving its production. In this study, we monitored the daily growth of BSF larvae reared with 10 diets with diverse nutritional quality and compared 7 growth models for quantifying growth performance. We found that BSF generally exhibited an S-shaped growth curve and that the Richards model was the best-fitting growth model. We estimated asymptotic growth limit (W∞) and constructed a time-series curve of absolute growth rate (AGR) by using the Richards model. We used Gaussian functions to estimate AGR parameters (maximum AGR, m; timing of maximum AGR, T; the deviation of AGR, d) to evaluate whether these parameters adequately quantify the growth performance of BSF. Correlation analysis showed that the AGR parameters were mostly independent of W∞ but were correlated with the duration of the larval stage, indicating that W∞ and the AGR parameters respond to different dietary factors.The results of pairwise comparisons showed that the diets rich in carbohydrates and protein had high W∞, m, and d, and early T.The diets with low levels of carbohydrates had low W∞, and the diets with low levels of protein had low m and d and delayed T. We conclude that the parameters estimated by the Richards model could be effective indices for evaluating the growth performance of BSF and their diet quality.

The olive fruit fly, Bactrocera oleae (Rossi), is one of the most damaging insect pests of olives worldwide, requiring the use of insecticides for fruit protection in many orchards. Olive fruit flies are attracted to volatile composunds, including a female-produced pheromone, and host-plant and bacterial volatiles. Preliminary laboratory bioassays were conducted for olive fruit fly attraction to over 130 yeast strains from among 400 that were isolated from B. oleae adults and larvae or other insects, infested olives, and potential feeding sites. Kuraishia capsulata, Scheffersomyces ergatensis, Peterozyma xylosa, Wickerhamomyces subpelliculosus, and Lachancea thermotolerans appeared to attract B. oleae as well or better than did torula yeast pellets (Cyberlindnera jadinii; syn. Candida utilis). Volatile compounds emitted by these yeast strains were chemically identified, and included isobutanol, isoamyl alcohol, 2-phenethyl alcohol, isobutyl acetate, and 2-phenethyl acetate. The behavioral response of B. oleae adults to these volatile compounds at three concentrations was tested in a laboratory Y-tube olfactometer. The same volatile compounds were also tested in the field. Isoamyl alcohol was more attractive than the other compounds tested in both laboratory and field bioassays. Isobutanol was not attractive to B. oleae in either laboratory bioassay or field bioassay. Identifying yeast volatiles attractive to the olive fruit fly may lead to development of a more effective lure for detection, monitoring, and possibly control of B. oleae.

The egg parasitoid Trissolcus vassilievi (Mayr) is a key natural enemy of sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae).This laboratory study examined how the aggregation of parasitoids varied in response to host density and numbers of foraging conspecifics. Five host densities (1, 2, 4, 8, and 15 clutches of E. integriceps eggs), were offered simultaneously to 1, 2, 4, 8, or 16 female wasps in a standardized arena (30 cm diameter) and patch residence times were recorded. Patch residence time was strongly correlated with parasitism, and increased as the number of host clutches increased up to eight, but declined when more clutches were offered. Wasps displayed low mobility and tended to remain in the patch initially encountered, even when it contained few egg masses. At higher wasp densities, patches were occupied more quickly, host exploitation began sooner, and per capita handling time was reduced. However, total patch residence times were similar across all densities. Thus, females responded to conspecifics with increased movement, which increased dispersal and resulted in a more homogeneous distribution of wasps among patches. Pseudo-interference, resulting from wasps remaining in some patches and neglecting others, had greater impact on final levels of host exploitation than did actual interference (patch abandonment following conspecific encounters).These phenomena resulted in decreased parasitoid searching rates and a 2-fold increase in host survival at higher wasp densities.

Deraeocoris brevis (Uhler) is a key predatory natural enemy of insects and mites in pear orchards in the United States. Insecticides used for crop protection in pear orchards and their residues can negatively affect populations of D. brevis. The focus of this study was to investigate the field-aged residual effects of lambda-cyhalothrin, spinetoram, and chlorantraniliprole insecticides on D. brevis through contact exposure. An airblast sprayer was used to apply the high label rate of insecticides on pear trees. Leaves were collected from the experimental trees at 1 d after treatment (DAT) and then at 7-d intervals up to 21 DAT. Adults and nymphs were exposed to leaves with insecticide residues or untreated control for 72 h in the laboratory. The nymphs that survived the treatments were reared until they emerged as adults.The surviving paired adults were reared until death. The treated nymphs were assessed for acute mortality, survival, developmental time, and the sex ratio if they emerged as adults. The treated adults were assessed for acute and chronic mortality, fecundity, fertility, and longevity. Both nymphs and adults exposed to leaf residues of lambda-cyhalothrin had significantly higher acute mortality compared with the insects exposed to the control. When compared with the control treatment, the toxicity of field-aged residues of lambda-cyhalothrin, chlorantraniliprole, and spinetoram can persist over a longer period of time. Similar patterns were observed in previous laboratory and field experiments on D. brevis. We discuss the residual effects of three insecticides through contact exposure of D. brevis.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a common pest of soybean, Glycine max (L.) Merrill (Fabales: Fabaceae), in North America requiring frequent scouting as part of an integrated pest management plan. Current scouting methods are time consuming and provide incomplete coverage of soybean. Unmanned aerial vehicles (UAVs) are capable of collecting high-resolution imagery that offer more detailed coverage in agricultural fields than traditional scouting methods. Recently, it was documented that changes to the spectral reflectance of soybean canopies caused by aphid-induced stress could be detected from ground-based sensors; however, it remained unknown whether these changes could also be detected from UAV-based sensors. Small-plot trials were conducted in 2017 and 2018 where cages were used to manipulate aphid populations. Additional open-field trials were conducted in 2018 where insecticides were used to create a gradient of aphid pressure. Whole-plant soybean aphid densities were recorded along with UAV-based multispectral imagery. Simple linear regressions were used to determine whether UAV-based multispectral reflectance was associated with aphid populations. Our findings indicate that near-infrared reflectance decreased with increasing soybean aphid populations in caged trials when cumulative aphid days surpassed the economic injury level, and in open-field trials when soybean aphid populations were above the economic threshold. These findings provide the first documentation of soybean aphid-induced stress being detected from UAV-based multispectral imagery and advance the use of UAVs for remote scouting of soybean aphid and other field crop pests.

Recent invasion of a new haplotype of sugarcane aphid (Melanaphis sacchari Zehntner) resulted in severe outbreaks of the aphids in sorghum (Sorghum bicolor L. Moench [Poales: Poaceae]) across the United States. Previous research and field observations suggested that both sorghum resistance and growth stage were important to their population dynamics in the field and hence effective and timely management to minimize economic losses associated with this pest.To explore this, we designed greenhouse experiments to quantify fecundity, prereproductive period, and longevity of sugarcane aphids across several vegetative and reproductive growth stages of a resistant (DKS 37-07) and susceptible (M77GB52 and DKS 38–88) sorghum hybrids commonly used in sorghum production. We found significant effects of sorghum resistance and growth stage on several life history traits and demographics parameters of sugarcane aphids. We did not, however, note any significant interactive effects of resistance and phenology on any of the response variables. Sugarcane aphids exposed to the susceptible sorghum produced significantly more offspring, had significantly greater intrinsic and finite rates of increase, and significantly shorter population doubling time than the aphids feeding on resistant sorghum. On the other hand, the impact of sorghum growth stage had more variable effects on life history of sugarcane aphids that were most frequently evident at the late reproductive stages. These outcomes support our hypothesis that sorghum in late stages of growth tends to be a better host for sugarcane aphids and highlight the importance of sorghum growth stage to sugarcane aphid life history and population growth potential.

Field experiments and supporting laboratory work were conducted to characterize the ability of the verde plant bug, Creontiades signatus (Distant), a boll-feeding sucking bug, to transmit a cotton seed and boll rot bacterial pathogen, Serratia marcescens (Bizio) (Enterobacteriales: Enterobacteriaceae). Serratia marcescens was originally isolated from bolls infested with verde plant bug in south Texas, and a Rifampicin resistant S. marcescens strain was used in transmission and retention experiments. Serratia-exposed and nonexposed adult verde plant bugs from a laboratory colony were placed individually on 5-, 6-, 7-, and 8-d-old bolls (postanthesis). The bacterial acquisition process did not apparently affect insect vigor based on similar average boll injury ratings observed across both exposed and nonexposed bugs. Cotton bolls caged with Serratia-exposed verde plant bugs had significantly greater presence of S. marcescens and cotton boll rot symptoms than bolls caged without bugs (no-insect controls) or nonexposed bugs. Transmission of the disease agent by verde plant bug was confirmed across all boll ages assayed. Incidence of diseased locules on 5- and 6-d-old bolls was the same or greater than on 7- and 8-d-old bolls. Verde plant bug was able to harbor the disease agent from 24- to 96-h postinfection, and transmission efficiency rates ranged from 54 to 62% during initial transmission and retention (transmission across two bolls fed upon consecutively) studies. Along with photographic evidence, the experimental data supported that boll damage associated with verde plant bug infestations was magnified when insects transmitted the cotton pathogen S. marcescens as demonstrated in this 2-yr field experiment.

The fall armyworm (Spodoptera frugiperda) (J. E. Smith) (Lepidoptera: Noctuidae), a major agricultural pest in the Western Hemisphere, has recently become established in Africa and Asia. This highly polyphagous species has potential to economically harm multiple crops. Contributing to this host range are two fall armyworm populations historically called ‘host strains’ that differ in host specificity. Understanding behaviors of the two strains is crucial to effective management of this pest. A major difficulty in such studies is that strains have long been considered morphologically indistinguishable, with molecular markers the only reliable means of identification. However, studies of fall armyworm in Colombia reported strain differences in wing morphology sufficiently large to potentially provide a more economical alternative method to determine strain. This study tested whether a similar phenotypic difference was present in Florida populations using geometric morphometric analysis of 15 anatomical landmarks on forewings of 182 specimens from three habitats associated with different host plants. Principle component and linear discriminant analyses identified significant differences in wing size and shape in comparison of strains from different habitats, but not between strains within the same habitat. Data indicate that apparent strain distinctions in wing phenotype are most likely a secondary consequence of differences in developmental growth patterns on different host plants combined with strain-biased host choice. Furthermore, Florida specimens showed much larger phenotypic overlap than observed for strains from Colombia. Together these findings suggest that wing morphology is probably not a reliable indicator of strain identity in field populations where different host plants are available.

Flea beetles (Phyllotreta spp.) are major insect pests in spring oilseed rape (SOSR; Brassica napus L.). Prohibited use of three neonicotinoid insecticides in the European Union means that there are currently no insecticide seed treatment options available. Insecticide spraying remains as a control option, but there is a need to estimate the economic threshold for crop injury. As a first step to this end, economic injury levels were determined for flea beetles in SOSR. Data from 16 field experiments were used to quantify the relationship between flea beetle crop injury and SOSR yield, and additional data from paired sprayed and unsprayed plots in 12 commercial SOSR fields were used to determine the reduction in crop injury from a pyrethroid spray. There was a strong linear negative effect of flea beetle injury with 19 kg/ha yield loss per percent crop injury to seedlings and a pyrethroid spray reduced crop injury by 39%. These results gave an economic injury level of 11% defoliation of SOSR seedlings under average oilseed rape prices and insecticide use costs in 2017. This is considerably lower than previously used nominal thresholds of 25–30% injury to cotyledons. Increased yields and increasingly cheaper pyrethroids might be the reason for the lower levels of crop injury that warrant chemical control. The economic injury levels presented here can be used to construct economic thresholds that preferably should also take into account crop growth stage, crop growth rate, and anticipated flea beetle activity.

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a major pest of corn in North and South America. It is managed primarily with transgenic corn-producing insecticidal proteins of Bacillus thuringiensis (Bt), but the development of resistance threatens their durability and necessitates the use of alternative management strategies. We conducted late-planted field trials during 2016 and 2017 in South Carolina using natural infestations. We evaluated the use of Bt and non-Bt corn hybrids in combination with foliar applications of chlorantraniliprole at varying infestation thresholds to protect field corn from infestation and damage and determine effects on grain yield. All Bt hybrids were more effective at reducing fall armyworm infestation rates and leaf injury than multiple insecticide sprays, and no Bt hybrid reached the lowest infestation threshold (20%) to require supplemental insecticide treatments, despite infestations in non-Bt corn reaching >68% in each year. The only Bt and/or insecticide treatment to significantly reduce ear feeding or the proportion of ears injured (mainly by Helicoverpa zea [Boddie]) was the Bt hybrid pyramid producing Vip3A. However, significant protection of yield was detected only in the Bt hybrids producing Cry1A.105 + Cry2Ab2. All Bt traits tested in this study were effective in reducing infestation and feeding damage from fall armyworm, although this did not always result in significant protection of yield. Our results demonstrate the potential and limitations of using chlorantraniliprole with Bt (when resistance is present) and non-Bt corn to manage this pest.

Coptoborus ochromactonus (Smith and Cognato) is one of the most common and important pests of balsa, Ochroma pyramidale (Cav. Ex Lam. Urb.), an economic pillar of the wood industry in Ecuador. Commercial balsa plantations have been expanded from humid to dry climate areas to limit insect damage, but basic knowledge is still lacking on the interaction of C. ochromactonus activity with variation in climate and plantation age. We investigated the effects of climate and host age on the seasonal flight activity of C. ochromactonus and its infestation rate and intensity, as well as the effect of age and individual infestation intensity on balsa dieback. Experiments were conducted in 1-, 2-, and 3-yr-old commercial balsa plantations located in areas of humid or dry climates. Seasonal flight activity (monitored with baited traps) differed between study sites and seasons. Increased flight activity was significantly correlated with higher relative humidity, higher mean temperature, and reduced precipitation during the dry season in the humid site and with increased mean and minimum temperature and increased precipitation during the rainy season in the dry site. Infestation rates by C. ochromactonus significantly increased with plantation age, especially in the humid site. Intensity of individual infestations (measured as number of successful insect entry holes per tree) was significantly influenced by both climate and plantation age, and it was particularly severe on 3-yr-old trees in the dry site. Percentage of foliage loss significantly increased with infestation intensity. Overall, our results can be relevant for devising preventive measures and suitable management strategies for this emerging pest in Ecuadorian wood plantations.

The woodwasp, Sirex noctilio Fabricius, is an exotic pest of Pinus L. in the southern hemisphere and North America, and it is an emerging threat in northeastern China. Adult woodwasps have numerous insect competitors for oviposition substrates, and developing larvae must compete for resources with other subcortical invaders. Its mutualistic fungus Amylostereum areolatum (Fr.) Boidon, is less competitive than many other fungal colonists present in pine ecosystems. This study investigated the effects of incidental, host-colonizing fungi on the growth and development of woodwasp larvae and A. areolatum. Fungi were isolated from dead S. noctilio larvae within galleries (primarily Trichoderma Pers, Ophiostoma Sydow, and Sphaeropsis Sacc.), and effects of these fungi on woodwasp brood survival were investigated via inoculations of S. noctilio-infested logs. Larval mortality was significantly increased in sample logs inoculated with Ophiostoma minus (Hedgc.) Sydow Phlebiopsis gigantea (Fr.) Jülich, Trichoderma atroviride Bissett, Trichoderma viride Pers, and Trichoderma harzianum Rifai. Inoculation of logs with O. minus resulted in the highest mortality and greatest reductions in wood moisture content. When grown on artificial media, these fungi grew faster than and inhibited growth of A. areolatum mycelium. We propose that the adverse effects of incidental fungi on the survival of S. noctilio larvae may be caused at least in part by an indirect mechanism involving inhibition of the fungal symbiont. The findings provide potentially valuable information for suppressing S. noctilio populations using microbial control agents.

The Asian longhorned beetle (Anoplophora glabripennis Motschulsky) continues to pose a significant risk to deciduous forests around the world. We assess Asian longhorned beetle-related risks in eastern Canada by generating current and future climate suitability maps, import-based likelihood of introduction estimates for each urban center in our study area, and potential economic impacts in both urban and natural settings. For the current period, climatic suitability for Asian longhorned beetle was highest in southern Ontario, but was projected to expand significantly northward and eastward by midcentury. High likelihood of Asian longhorned beetle introduction was associated with large urban centers, but also smaller centers with high levels of pest-associated imports. Potential costs for the removal and replacement of Asian longhorned beetle-impacted street trees ranged from CDN$8.6 to $12.2 billion, with the exact amount and city-level ranking depending on the method used to calculate risk. Potential losses of merchantable maple (Acer) timber were estimated at CDN$1.6 billion using provincial stumpage fees and CDN$431 million annually when calculated using a combination of economic and forestry product statistics. The gross value of edible maple products, which could potentially be affected by Asian longhorned beetle, was estimated at CDN$358 million annually. These values can help inform the scale of early detection surveys, potential eradication efforts, and research budgets in the event of future Asian longhorned beetle introductions.

Between 1996 and 2003 field studies were conducted in wild blueberry, Vaccinium angustifoliumAiton (Ericales: Ericaceae) to determine action thresholds for the blueberry maggot fly, Rhagoletis mendax Curran (Diptera: Tephritidae). Thresholds were based upon cumulative fly trap captures on baited Pherocon AM traps. The cumulative numbers of R. mendax flies captured over time was a significant predictor of infested fruit levels (maggots/liter blueberries). Fifty percent of the variance in fruit infestation is explained by fly captures. Based upon this relationship, the University of Maine Cooperative Extension has recommended action threshold of 10 cumulative fly captures/trap. However, this threshold is liberal in terms of risk as only 50% of the variance in fruit infestation is explained by fly captures. The dynamics of colonization rate and fly physiological status entering fruit-bearing fields might partially explain the variance in the action threshold. The majority of flies emerge from pruned fields or along forest scrub/shrub field edges, and it takes between 1 and 10 d (mean = 4.1 ± 0.9 d) for the populations to enter adjacent fruit-bearing fields. Flies dispersed from pruned fields at a decreasing rate the farther they dispersed.The rate of dispersal into fruit-bearing wild blueberry fields also depends upon the overwintering site quality. Sites with fruit exhibited both delayed colonization and lower colonization rates into fruit-bearing fields than adjacent pruned fields with no fruit. We also found that as the season progressed the proportion of flies capable of laying eggs varied greatly by location and year.

Food baits are effective and widely used tools for monitoring diversity and abundance of tephritid fruit flies. Four food-baits—Nulure, BioLure, Mazoferm at 3 and 6%, and Torula yeast—were used in multi-lure traps over a 4-yr period in mango orchards in three Benin agro-ecological zones (AEZ) representing a large swath of environments in western Africa. Twelve tephritid fruit fly species were captured during the trials, with the highest richness in the Forest Savannah Mosaic (FSM), followed by the Southern Guinea Savannah (SGS), and the Northern Guinea Savannah (NGS) AEZ. Despite previous reports of displacement, the native species Ceratitis cosyra remained the dominant tephritid species in mango orchards in the NGS, with the invasive and exotic species Bactrocera dorsalis dominating the tephritid fauna in the SGS and FSM. Torula yeast captured the greatest number of fruit flies in each AEZ. Mazoferm-3% captures were similar to Torula yeast, except for lower captures in the NGS where it tended to harden. The rank order of relative efficiency indices (REI) of the food baits (relative to Torula yeast) is Mazoferm-3% > Nulure > Mazoferm-6% and BioLure. The latter captured more Ceratitis spp. than all the other baits, particularly at very low Ceratitis spp. abundance. To our knowledge, the study is the first to report relative efficiency indices for the selection of food baits in monitoring diversity and abundance of fruit flies. Ecological and practical implications for the use of food baits in comparison with male lures are discussed.

In cucurbit crops such as watermelon, implementation of integrated pest management (IPM) is important due to the high reliance on bees for fruit set, along with mounting evidence of the risks of insecticide use associated with pollinator health.Yet, IPM adoption, on-farm pesticide use behaviors, their costs, and impacts on the primary insect pest (striped cucumber beetle, Acalymma vittatum F.) are poorly known in one of the key watermelon-growing regions, the Midwestern United States.To better understand how to implement IPM into watermelon production, we assessed pest management practices on commercial watermelon farms using 30 field sites in Indiana and Illinois over 2 yr in 2017 and 2018. Across all sampling dates, beetles never crossed the economic threshold of five beetles/plant at any farm and most were maintained at densities far below this level (i.e., <1 beetle/plant). Moreover, we documented a wide range of insecticide inputs (mean ca. 5 applications per field per season; max. 10 applications) that were largely dominated by inexpensive foliar pyrethroid sprays; however, insecticide application frequency was poorly correlated with pest counts, suggesting that most of these applications were unnecessary. We calculated that the cost of the average insecticide program far exceeds the cost of scouting, and thus IPM is estimated to save growers ca. $1,000 per field under average conditions (i.e., field size, insecticide cost).These data strongly indicate that current management practices on commercial farms in the Midwest would benefit from implementing more threshold-based IPM programs with potential increases in both farm profitability and pollination services.

Chalcodermus aeneus Boheman (Coleoptera: Curculionidae) has been the most destructive insect pest of black-eyed peas or cowpeas, Vigna unguiculata L. (Fabales: Fabaceae), over the last century in the southeastern United States. The historical distribution of this semitropical pest suggests the likelihood that diapause plays a key role in the overwintering success in parts of the United States. However, this report is the first to document biological evidence for diapause in C. aeneus. Our study assessed larval emergence from cowpea pods in the summer to fall growing seasons, egg development in female adults over the first (summer) and second (fall) generations, and adult emergence from infested soil after the first and second generations.There was a clear reduction in larval emergence from summer to fall. Egg and follicle development in female C. aeneus dropped off dramatically by September of each year.There was an extended emergence pattern of weevil adults from the soil in the fall as compared to the summer generation. Any future regional management of cowpea curculio will have to take into account the ability of this insect to diapause, thereby increasing its capacity to overwinter in regions where the cowpea crop, a warm-season, semitropical plant, is terminated with winter freezing temperatures.

Flea beetles, are common pests of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) and eggplant Solanum melongena L. (Solanales: Solanaceae), but little is known about the flea beetle populations in Virginia, their impact on yield, or the most effective control methods.This research investigates flea beetle populations and the impact of their feeding injury on cabbage and eggplant in Southwest Virginia and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers (2015, 2016). Crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), and striped flea beetle, Phyllotreta striolata Fabr. (Coleoptera: Chrysomelidae) were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch) (Coleoptera: Chrysomelidae), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) (Coleoptera: Chrysomelidae) were found on eggplant. To evaluate the impact of flea beetle feeding on these plants flea beetle densities and defoliation were assessed weekly and individual plant, as well as whole plot yields, assessed at harvest. For cabbage, significant yield reductions were observed between 1 and 20% and >60% defoliation. Similarly, significant yield reductions were observed between 41 and 60% and >60% defoliation for eggplant.The efficacy of various insecticides was also evaluated. Soil application of the systemic neonicotinoid dinotefuran, imidacloprid, and the foliar-applied bifenthrin resulted in the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them.

Toxicity profiles of four aliphatic (α-pinene, cyclononanone, limonene, nerolidol), four aromatic (β-thujaplicin, carvacrol, eugenol, tropolone) essential oil components (EOCs), and permethrin were investigated against three strains of German cockroach, Blattella germanica (L.). The strains include a susceptible strain (S), and two multi-resistant strains – strains D and E. Also, a synergism bioassay, using piperonyl butoxide (PBO) was conducted.The most toxic EOCs were aromatic EOCs carvacrol, eugenol, and tropolone, followed by aliphatic EOC limonene; all had LD₅₀ values of <0.7 mg/µl. Four of the EOCs were equally toxic against all the strains, with carvacrol being the most toxic, followed by eugenol, tropolone, and α–pinene.The other four EOCs were more toxic against strain S than against the two resistant strains. Permethrin was significantly more toxic to strain S (LD₅₀ = 0.056 µg/µl) compared with the resistant strains (D = 2.138 µg/µl, E = 1.730 µg/µl).Toxicity of aliphatic EOCs correlated positively with their molecular weight against strain E only, whereas both molecular weight and vapor pressure of aromatic EOCs correlated significantly with toxicity in all strains. Strain D exhibited the greatest resistance (RR of 6.7) to EOCs, and synergism to the aliphatic EOC cyclononanone. Clear synergism with PBO was observed in permethrin against resistant strains, but not in all of the EOCs, suggesting multiple resistance mechanisms in the resistant cockroaches.These findings give insight on the potential of EOCs to be incorporated as parts of an IPM approach to managing insecticide resistant German cockroaches.

Termite colony size can influence its foraging activity, reproductive maturity, and, for pest species, potential for structural damage. Estimating colony size of subterranean termite species in field conditions has been challenging owing to their extensive foraging territory and their cryptic nesting habit and has primarily relied on mark–recapture methods. With laboratory-reared colonies in individual containers, determining colony size can be achieved by processing all termites from the nest material, which can be labor intensive and partially destructive. However, with the recent rise in the need of large laboratory colonies for use in colony-wide experimental protocols, there was an imperative to develop a procedure to estimate initial colony sizes without imposing a major stress on colonies before an experiment. In this study, the average daily wood consumption of whole colonies was used to infer the colony size of two Coptotermes, Wasmann (Blattodea: Rhinotermitidae) species and their hybrids in laboratory-rearing conditions. Correlations between the daily wood consumption and several demographic variables within colonies were established. Linear models varied across all species mating types with R² values greater than 0.8 for all demographic variables. For colonies from all mating combinations, Pearson's correlation coefficient values were greater than 0.94 between their daily wood consumption and both the number of workers and total number of termites, and greater than 0.91 between daily wood consumption and colony mass. Therefore, in colonies with fixed laboratory conditions, their average daily wood consumption determination, which is nondestructive on colonies, can be used to infer colony size of subterranean termites.

The Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex comprises important pests and virus vectors in agricultural crops worldwide. In China, B. tabaci has spread to more than 20 provinces and caused severe losses of vegetables, fruits, and ornamental plants. However, B. tabaci has developed resistance to many insecticidal classes in Shandong Province, eastern China. In this study, we investigated the cryptic species, insecticide resistance and detoxifying enzymes of B. tabaci from six representative locations exhibiting severe damage in Shandong. At four of the six locations, B. tabaci Mediterranean (MED) comprised 100% of the samples collected. In a further two locations, species composition was predominantly (>94%) MED with B. tabaci Middle East–Asia Minor 1 (MEAM1), comprising a low proportion (<6%) of the samples collected. For all field populations, avermectin was the most effective insecticide against adult B. tabaci, pyriproxyfen had a significant effect on B. tabaci eggs and field populations were susceptible to pymetrozine. Six field populations of B. tabaci have developed low-to-moderate resistance to neonicotinoids. The detoxifying enzyme activity of carboxylesterase, glutathione S-transferase, and multifunctional oxidase were quantified. Multifunctional oxidase and glutathione S-transferase activity were positively correlated with insecticide resistance in several B. tabaci populations.

The citrus red mite, Panonychus citri (McGregor), is an important spider mite pest in citrus producing areas. Owing to long-term acaricide exposure, resistance has evolved rapidly in recent years. To evaluate the extent of resistance, seven field mite populations sampled from various geographical locations in China during 2015–2018 were tested using the leaf-dip bioassay method to determine their susceptibilities to four acaricides. In comparison with the susceptible strain maintained in the laboratory, low or moderate levels of fenpropathrin resistance, while no resistance to abamectin or cyflumetofen, were found among populations sampled from Liangping, Wanzhou, Daying, and Anyue in Southwestern China during the test period. High levels (>1,000-fold, with LC₅₀ values that were greater than the recommended concentration) of resistance to fenpropathrin had evolved in field populations from Southern China, including Guilin, Nanning, and Yuxi, when compared with that of the susceptible strain. Populations from Guilin and Nanning also evolved high resistance levels to abamectin (1,088-fold and 1,401-fold) and cyflumetofen (2,112-fold and 9,093-fold). All the populations sampled in 2018 showed a moderate or high resistance to bifenazate. Generally, field populations of citrus red mites from Southwestern China were more sensitive to the tested acaricides than those of Southern China.The data provide a foundation for developing acaricide resistance management strategies in these regions.

Euschistus heros (Fabricius, 1798) and Dichelops furcatus (Fabricius, 1775) are key pests of agricultural crops in Brazil. Chemical insecticides are the main control tactic used against these species. Here, we investigated the susceptibility of E. heros and D. furcatus from distinct regions to the mains insecticides used to stink bugs control in Brazil. Field populations of these species were collected throughout the 2017–2019 crop seasons and insects were exposed to insecticides in dip-test bioassays using fresh green bean pods. Populations of E. heros exhibited low variation in the susceptibility to acephate (LC₅₀ = 172.2 to 1,008 µg a.i. per ml), and thiamethoxam (LC₅₀ = 28.8 to 433.9 µg a.i. per ml); resistance ratios were less than 5.9- and 15.1-fold, respectively. In contrast, these populations had higher variation in the susceptibility to bifenthrin (LC₅₀ = 26.7 to 636.1 µg a.i. per ml) and lambda-cyhalothrin (LC₅₀ = 10.0 to 636.1 µg a.i. per ml); resistance ratios reaching 23.8- and 63.6-fold, respectively. Susceptibility monitoring data indicated a higher susceptibility of E. heros to the manufacturers field‐recommended rates of acephate, lambda-cyhalothrin + thiamethoxam, and bifenthrin + acetamiprid than lambda-cyhalothrin. Populations of D. furcatus exhibited low variation in the susceptibility to acephate (LC₅₀ = 219.2 to 614.1 µg a.i. per ml), bifenthrin (LC₅₀ = 62.8 to 197.4 µg a.i. per ml), and lambda-cyhalothrin (LC₅₀ = 189.5 to 2,538 µg a.i. per ml); resistance ratios were less than 13.4-fold. In summary, populations of E. heros are less susceptible to pyrethroids, while populations of D. furcatus have similar susceptibility to the insecticides evaluated.

Soybean aphid, Aphis glycines Matsumura, remains the most economically damaging arthropod pest of soybean in the midwestern United States and southern Canada. Foliar applications of a limited number of insecticide modes of action have been the primary management tactic, and pyrethroid resistance was documented recently with full concentration–response leaf-dip and glass-vial bioassays. Full concentration–response bioassays can be cumbersome, and a more efficient assessment tool was needed. In this study, we implemented a diagnostic-concentration glass-vial bioassay using bifenthrin and λ-cyhalothrin. Bioassays were conducted with field-collected soybean aphid populations to assess the geographic extent and severity of resistance to pyrethroids. In 2017, 10 of 18 and 11 of 21 field populations tested with bifenthrin and λ-cyhalothrin, respectively, had mean proportion mortalities less than the susceptible laboratory population. In 2018, 17 of 23 and 13 of 23 field populations tested with bifenthrin and λ-cyhalothrin, respectively, had mean proportion mortalities less than the susceptible laboratory population. Populations collected after reported field failures of a pyrethroid insecticide generally had mean proportion mortalities less than the susceptible laboratory population. In both years, there was a strong correlation between chemistries, which suggests cross-resistance between these insecticides.The diagnostic-concentration glass-vial bioassays reported here will provide the foundation for an insecticide resistance monitoring program with the ability to determine practical levels and geographic extent of insecticide resistance.

Farmers face many choices when selecting seed for soybean (Glycine max (L.) Merr.) production, including highly desired herbicide tolerance traits. Despite the convenience of herbicide tolerance, resistant weeds and technology fees may reduce utility and profitability of these varieties, especially when commodity prices are low. Sporadic outbreaks of soybean aphid (Aphis glycines Matsumura, Hemiptera: Aphididae) that require insecticide use for optimal yield can be a further complication for farmers in Iowa. Soybean aphid-resistant varieties are commercially available, but in limited genetic backgrounds without herbicide tolerance. We hypothesized yield and value of resistance traits will vary based on the environment. We established plots at two locations with different risks of soybean aphid outbreaks and used two planting dates at each location to mimic different yield environments. In 2016 and 2017, we planted four varieties that varied in their susceptibility to soybean aphids and glyphosate, and applied insecticides if aphid populations reached an economic threshold. Regardless of genetic background, aphid-resistant varieties prevented populations from reaching the economic threshold at all environments. We observed no significant difference in yield between resistant and susceptible varieties, revealing this trait is as effective at protecting yield as an insecticide application on susceptible varieties at the high-risk location. We also explored the value of each variety in different environments. Resistant varieties produced greater potential net revenue than susceptible varieties at the high-risk location, while the opposite occurred at the low-risk location. Resistant varieties with herbicide tolerance, if made available, would be the most valuable across all environments.

Soybean vein necrosis virus (SVNV) was first identified in Arkansas and Tennessee in 2008 and is now known to be widespread in the United States and Canada. Multiple species of thrips transmit this and other tospoviruses with Neohydatothrips variabilis (Beach) (soybean thrips) cited as the most efficient vector for SVNV. In this study, 18 soybean, Glycine max (L.) Merr., genotypes were evaluated in four experiments by infesting plants with noninfected and SVNV-infected thrips using choice and no-choice assays. In both choice experiments with noninfected and SVNV-infected thrips, the lowest number of immature soybean thrips occurred on plant introductions (PIs) 229358 and 604464 while cultivars Williams 82 and Williamsfield Illini 3590N supported higher counts of mature thrips. The counts between the two assays (noninfected and SVNV-infected thrips) were positively correlated. In both no-choice experiments with noninfected and SVNV-infected thrips, counts of thrips did not differ by soybean genotypes. Further studies are needed to characterize the inheritance and mechanisms involved in the resistance found in the choice assay.

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is an agronomically important pest that severely limits maize (Zea mays (Linnaeus) [Poales: Poaceae]) production.This migrant insect devastates maize plants in many countries threatening the livelihood of millions. Quantitative trait loci (QTL) were mapped to identify chromosomal regions that control resistance to fall armyworm leaf-feeding and to identify molecular markers linked to the target loci for use in marker-assisted selection (MAS). A bi-parental mapping population, comprising 243 F_2:3 families from the cross Mp705 (resistant) × Mp719 (susceptible), was evaluated for fall armyworm leaf-feeding damage under artificial infestation over 3 yr. A linkage map comprised of 1,276 single-nucleotide polymorphism and simple sequence repeat molecular markers was constructed. Quantitative trait loci analyses identified two major QTL in bins 4.06 and 9.03 that when combined, explained 35.7% of the phenotypic variance over all environments. Mp705 was responsible for the leaf-feeding damage reducing alleles for both large effect QTL and most of the small effect QTL identified in this study. The QTL identified in bin 9.03 co-locates with a previously identified QTL that controls resistance to leaf-feeding damage in maize by fall armyworm and other lepidopteran insects.The QTL in bin 4.06 is a new source of resistance identified in this study. Beneficial alleles derived from Mp705 for the application of an integrated QTL-MAS approach could accelerate breeding efforts to minimize fall armyworm leaf-feeding in maize.

Plant–herbivore interactions can be influenced by plant developmental stages. Effects of four different developmental stages of pomegranate fruit (Hazelnut size, Walnut size, Juicy, and Ripe) were investigated on life table parameters, nutritional yield, and energy contents (protein, glycogen, and lipid) of Ectomyelois ceratoniae (Zeller) under controlled conditions in two pomegranate cultivars, namely Shahvare-Danesefid and Esfahani-Daneghermez as susceptible and resistant cultivars, respectively. Biochemical characteristics of the four developmental stages were determined, and a correlation was made with life-history and nutritional responses of E. ceratoniae. Significant differences were observed in developmental time and adult fecundity of E. ceratoniae across various tested stages in both pomegranate cultivars. The highest value of intrinsic rate of increase (r_m) was found in Juicy and lowest in Hazelnut-size stage of Shahvare-Danesefid. The highest rm value was on Walnut-size and Juicy stages, and the lower rate was obtained from the feeding of E. ceratoniae on Ripe and Hazelnut-size stages in Esfahani-Daneghermez. A higher relative growth rate (RGR) was observed in Juicy (in Shahvare-Danesefid) and Walnut-size stages (in Esfahani-Daneghermez) when compared with other developmental stages tested. Life-history parameters of E. ceratoniae were correlated with biochemical qualities of pomegranate stages. Results indicated Juicy (Shahvare-Danesefid) and Walnut-size stages (Esfahani-Daneghermez) were relatively susceptible pomegranate stages, and Hazelnut-size and Ripe stages were unsuitable for feeding of E. ceratoniae in Shahvare-Danesefid and Esfahani-Daneghermez, respectively. Findings of this research could aid in the development of integrated management programs of E. ceratoniae in pomegranate orchards.

Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20–80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists.The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.

Laurel wilt and Fusarium dieback are vascular diseases caused by fungal symbionts of invasive ambrosia beetles (Coleoptera: Curculionidae: Scolytinae). Both diseases threaten avocado trees in Florida. Redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of the laurel wilt pathogen, Raffaelea lauricola, but in recent years this symbiont has been transferred laterally to at least nine other species of ambrosia beetle, which now comprise a community of secondary vectors. Dieback disease, caused by Fusarium spp. fungi, is spread by shot hole borers in the Euwallacea fornicatus species complex. In this study, we conducted field tests in Florida avocado groves to compare efficacy of four trap designs for detection of Scolytinae. Treatments included an 8-funnel Lindgren trap, black 3-vane flight interception trap, green 3-vane interception trap, white sticky panel trap, and an unbaited sticky panel (control). In two tests targeting E. nr. fornicatus and X. glabratus, traps were baited with a two-component lure (α-copaene and quercivorol). In a test targeting other species, traps were baited with a low-release ethanol lure. For E. nr. fornicatus, sticky panels and black interception traps captured significantly more beetles than Lindgren traps; captures with green traps were intermediate. With ethanol-baited traps, 20 species of bark/ambrosia beetle were detected. Trap efficacy varied by species, but in general, sticky traps captured the highest number of beetles. Results indicate that sticky panel traps are more effective for monitoring ambrosia beetles than Lindgren funnel traps, the current standard, and may provide an economical alternative for pest detection in avocado groves.

Insect abundance is commonly recorded in the form of discrete counts taken from plants. Analyses of these counts provide information about spatial distributions and population structure. A study was conducted in the Lower Rio Grande Valley of Texas during April and May 2014 to determine how populations of potato psyllids [Bactericera cockerelli (Šulc)] within three potato fields change over time. It was found that potato psyllid populations in these potato fields frequently changed both spatially and temporally. Chi-square goodness of fit tests and Akaike's Information Criterion indicated that the frequency distributions of potato psyllid counts conformed to a negative binomial distribution, implying an aggregated spatial pattern. Variance–mean ratios were always much larger than one, also implying spatially clumped populations. However, with a few exceptions, a Spatial Analysis by Distance IndicEs analysis showed that potato psyllid counts were mostly random in space, the clumping generally occurring on individual potato plants and rarely involving groups of potato plants in close proximity.Trends in proportions of plants infested by at least one potato psyllid and the clumping parameter k were similar for all three potato fields. Potato psyllid spatial population structure is a dynamic process that involves continuous adult movements leading to substantial redistribution of potato psyllids over limited time spans of 2 to 3 d. By capturing elements of their spatial and temporal patterns of redistribution, the study reported here is a step towards a better understanding of the population dynamics and movement of potato psyllids.

The lesser mealworm, Alphitobius diaperinus (Panzer), is a serious pest, but at the same time has been authorized in European Union (EU) for feed in aquaculture. In this study, we investigated, in laboratory bioassays, the population growth of this species, on a wide variety of commodities. In four series of bioassays, we studied the development of A. diaperinus population on various intact cereal grains, on soft wheat grains with different percentages of cracked kernels, on non-grain amylaceous commodities and on a variety of non-amylaceous commodities. Briefly, 20 g of each commodity were put separately inside plastic cylindrical vials.Then, 20 A. diaperinus adults were placed inside each vial and all vials were incubated at 30°C and 55% r.h. After 30 d, the vials were opened and the progeny production was evaluated. Alphitobius diaperinus showed a clear preference in amylaceous commodities, but in contrast, poor development was recorded on the non-amylaceous commodities tested. Hence, it developed well in most of the cereal intact grains tested, with the hard and soft wheat being the most suitable. Additionally, most non-grain amylaceous commodities were suitable, to a various degree, for the population growth of A. diaperinus.The increase of the percentage of cracked wheat positively affected the population growth of A. diaperinus.To our knowledge, this is the first study that examined the suitability of a wide range of commodities for the population growth of A. diaperinus.

Fumigation with methyl bromide has been a long established and effective method for controlling many pests of stored products, including the key major pests that infest dry-cured hams, aged cheese, and other value-added durable stored products. Methyl bromide had been widely used for the disinfestation of dry-cured ham facilities in the United States, but is now phased out of use since it is an ozone-depleting substance. This paper reports laboratory studies to evaluate the efficacies of methyl bromide and phosphine for controlling two of the key arthropod pests of dry-cured hams and aged cheeses. Larvae of the red-legged ham beetle, Necrobia rufipes (Fabricius), were the most tolerant life stages when treated with either phosphine or methyl bromide for 48 h exposure at 23°C, whereas eggs of the mold mite, Tyrophagus putrescentiae (Schrank), were slightly more tolerant than mobile stages for both compounds. Under laboratory conditions, complete control was achieved for the both species with concentrations of 0.85 and 4.0 g/m³ of phosphine and methyl bromide, respectively, at 48 h exposure. The results give new information for judicious use of the existing stocks of methyl bromide, whether for pest mitigation or to help in developing a quarantine treatment schedule with that gas. Phosphine shows good potential as an effective alternative to methyl bromide, but if it was to be adopted as a fumigant in the dry-cured ham industry, methods to prevent metal corrosion would need to be designed and effectively implemented.

The honey bee, Apis mellifera L. (Hymenoptera: Apidae), is a model organism for pollinators in risk assessment frameworks globally.The acute toxicity tests with adult honey bees for contact and oral exposure are part of the requirements for pesticide registration and are typically conducted with the active ingredient. A question often asked is if the typical end-use product (TEP) is more toxic than the technical grade active ingredient (TGAI) to honey bees. We explored this question by mining publicly available databases from regulatory agencies worldwide, where testing with theTEP is required.The objective of this study was to determine whetherTEPs are comparable in toxicity to the TGAI. The dataset was analyzed via a 3 × 3 contingency table with toxicity categories, as the data cannot be computed for regression analysis. Of the 151 active ingredients with reported endpoints for contact exposure, 28 were classified as either moderately or highly toxic, 123 were classified as practically nontoxic, and 3 were inconclusive. Only two (1.3%) were reclassified from nontoxic to moderately toxic as theTEP. Of the 141 active ingredients with reported endpoints for oral exposure, 23 were classified as moderately or highly toxic, 113 were classified as practically nontoxic, and 5 were inconclusive. Only five (3.6%) were reclassified from nontoxic to moderately toxic as theTEP. Fewer than 5% of the totalTEPs evaluated (contact and oral) were shown to be more toxic than theTGAI, suggesting that the risk assessments ofTGAIs would be sufficiently protective to pollinators at the screening laboratory level.

Tagosodes orizicolus (Muir) is the most important pest of rice in Latin America. Besides causing direct damage called hopperburn from feeding on and ovipositing in rice leaves, this insect pest also transmits rice hoja blanca virus (RHBV, Family Phenuiviridae, Genus Tenuivirus) in a persistent-propagative manner. This pathosystem can cause up to 100% yield loss in Latin American rice fields. T. orizicolus and RHBV symptoms were detected in Louisiana, Mississippi, and Florida rice fields in the 1950s, 1960s, and 1980s. However, neither has been detected in the United States since. Two outbreaks of T. orizicolus on ratoon rice occurred in the fall of 2015 and 2018 in counties southwest and south of Houston, TX. Insects were collected from ratoon rice fields by sweep net methods. Insects from the 2015 and 2018 outbreaks were tested individually and in pools of 10, respectively, for RHBV infection and the cytochrome oxidase 1 (CO1) gene from Delphacidae. No insects were positive for RHBV, however, all samples yielded amplicons for the CO1 gene. Furthermore, the CO1 gene from five 2015 individuals was sequenced and found to have a 100% identity to the Fer26_Argentina and 99.81% identity to the DEL074 Venezuela isolates of T. orizicolus. Five new sequences from 2015 individuals have now been deposited in GenBank. It is imperative to stay up to date on the potential invasion and establishment of this exotic pest of rice in Texas and other rice-growing regions of the United States through continued monitoring and research.

The false codling moth Thaumatotibia leucotreta (Meyrick), is an invasive species in Israel. In order to carry out a classical biological control program, the African egg parasitoid Trichogrammatoidea cryptophlebiae (Nagaraja) was recently introduced into Israel, and nontarget host risk assessment was performed as required. In no-choice tests we determined that T. cryptophlebiae was unable to develop in eggs of four nontarget Lepidopteran species: Pectinophora gossypiella (Saunders), Spodoptora littoralis (Boisduval), Ephestia kuehniella (Zeller), and Belenois aurota (Fabricius). Conversely, it developed in three Lepidopteran species eggs of the Tortricidae family: Cydia pomonella (Linnaeus), Lobesia botrana (Denis and Schiffermüller), and Epiblema strenuana (Walker). Epiblema strenuana eggs showed the lowest parasitism level among all tested moth eggs of the Tortricidae family. The progeny production of parasitized false codling moth eggs was similar to that of C. pomonella eggs, but smaller than that of L. botrana eggs. However, moth egg and parasitoid clutch sizes were smallest on L. botrana eggs and largest on C. pomonella eggs. In choice bioassays, T. cryptophlebiae significantly preferred to parasitize T. leucotreta eggs over the eggs of C. pomonella, L. botrana, and E. strenuana. Moreover, the choice of T. leucotreta eggs over the eggs of L. botrana was not affected by the parasitoids' rearing histories. Our data support the assumption that T. cryptophlebiae develops only in moth species of the Tortricidae family. Thus, the risk that it may attack nontarget species is low.

The spatial distribution of Lycorma delicatula (White) egg masses on three species of trees were studied in Pennsylvania. Five tree-of-heaven, five black walnut, and one Siberian elm trees were felled in early spring 2019 to sample for egg masses. Each egg mass was marked for its cardinal direction, position in the tree, height above ground, and spread from the bole. A total of 214 egg masses were found on tree-of-heaven and black walnut, with 38.3, 29.4, 22.0, and 10.3% on the north, west, south, and east quadrant, respectively. No significant difference in cardinal direction was found for either species. Equal number of egg masses were found on branches and boles on tree-of-heaven. However, significantly more egg masses were found on branches (96.5%) compared to boles (3.5%) on black walnut. Egg masses were laid at 0.30–12.92 and 0.70–17.00 m above ground, with most on boles/higher branches and middle/lower branches for tree-of-heaven and black walnut, respectively. Significant effect of height above ground was found for black walnut, with more egg masses found at 4–6 m compared to 0–2, 12–14, and 14–16 m. Significant effect of spread from the bole was found for tree-of-heaven, with more egg masses found at 0–2 m compared to 2–4 and 4–6 m. The 24 egg masses on the Siberian elm were mostly found on east quadrant branches 0–2 m above ground and within 2 m from the bole. Variation in tree branching patterns and difference in egg mass distribution of other forest pests were discussed.

The German cockroach, Blattella germanica L., is a hemimetabolous insect pest of economical and medical importance. N,N-diethyl-3-methylbenzamide (DEET) is an insect repellent whose effect on this species has received very little attention.The objective of this work was to determine whether the behavioral response of B. germanica to DEET varies along its life cycle. DEET repellence was assessed in small, medium, and large nymphs, and in adults of both sexes, all originated from the same laboratory colony (CIPEIN).The experimental arena consisted in a piece of filter paper treated with repellent on one half (195 µg/cm²) and solvent alone on the other half. A cockroach was placed on the filter paper, and its behavior was filmed. An image analyzer was used to quantify how long the insect spent on each side of the paper. As a control, a cockroach was exposed to a piece of filter paper treated with solvent (acetone) alone. Each assay was repeated independently six times. Distribution coefficient (DC) values were calculated, a parameter that ranges between 0 (attraction) and 1 (repellence). Small nymphs were more sensitive to DEET (mean DC = 0.93).The mean DC values of the other groups varied between 0.62 (medium nymphs) and 0.71 (male adults). The group of medium nymphs was the only one whose behavior was not significantly altered by exposure to DEET.The results show the importance of assessing insect repellents at different stages of the insect's life cycle in order to obtain a complete panorama of its effect.

There is high demand for accurate insect sampling methods to inform integrated pest management strategies. Despite widespread application, existing sampling methods, such as portable aspirating and sweep netting, can result in overrepresentation of prominent pests, underrepresentation of natural enemies, and damage to plants. In this study, we test a novel device for insect sampling via anesthetization. Specifically, we test the effect of CO₂ (application pressure and duration of exposure) on Lygus hesperus Knight (Hemiptera: Miridae) anesthetization in the laboratory and on insect community density in a strawberry agroecosystem. Carbon dioxide application proves an effective means of anesthetization compared to negative controls, and an increase in net CO₂ exposure results in a decrease in time until L. hesperus anesthetization. Field results indicate the CO₂ method collects more parasitoids and thrips than a portable aspirator, and at the 50 PSI application pressure and 15-s exposure, the CO₂ method results in a comparable number of pests collected as the research standard, a portable aspirator with 8-s aspiration time. Benefits of the CO₂ method include minimal plant damage, highly explicit spatial and temporal data, and scalability.

Brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species in the United States that attacks a wide variety of agricultural commodities including fruits, vegetables, agronomic crops, and ornamental plants. Populations of H. halys adults were collected from four and six states in 2017 and 2018, respectively, and tested using topical applications to establish baseline levels of susceptibility to two commonly used insecticides, bifenthrin and thiamethoxam. A Probit-estimated (95% fiducial limits) LD₅₀ and LD₉₉ of 2.64 g AI/L (1.2–3.84 g AI/L) and 84.96 g AI/L (35.76–716.16 g AI/L) for bifenthrin, and a LD₅₀ and LD₉₉ of 0.05 g AI/liter (1.14E-5–0.27 g AI/L) and 150.11 g AI/L (27.35–761,867 g AI/L) for thiamethoxam, respectively.These baseline levels can be used for future insecticide resistance monitoring in H. halys.

The spotted-wing drosophila, Drosophila suzukii Matsumura, is an exotic species in North America and represents a major threat to fruit production. Efforts to manage D. suzukii have focused primarily on insecticides, but such controls may, at times, be unreliable, given that D. suzukii larvae are often ensconced within fruit.The fruit interior, however, may represent suitable foraging substrates for carnivorous/entomopathogenic nematodes. In preliminary trials, a rare nematode species, Oscheius onirici Torrini et al., was shown to be highly virulent against D. suzukii when the nematodes were applied directly to fly larvae. To address the more important question of whether this nematode would be as virulent when applied to fruit, we set up assays in which blueberries were infested with D. suzukii larvae and then sprayed with O. onirici infective juveniles (IJs). Across two laboratory trials, O. onirici IJs suppressed D. suzukii puparia by 78.2%. Oscheius onirici IJs were able to search effectively within fruit substrates, find the fly larvae therein, and kill the flies before they could pupariate. Oscheius onirici, therefore, may represent a viable new bio-control agent for D. suzukii management and should be field-tested across a broader diversity of cropping systems.