Commercial beekeepers need healthy, productive honey bee (Apis mellifera L.) colonies, even when the landscape lacks adequate pollen forage to sustain the colonies. As a result, many commercial beekeepers spend significant money and labor on the use of pollen substitutes in their colonies. However, there is little consensus in the literature about the benefits and drawbacks of pollen substitute use on honey bee colony health. In order to understand this critically, it is important to know first how honey bees distribute pollen substitute patties throughout their colonies. We traced the fate of three commercially available pollen substitute patties (MegaBee, UltraBee, AP23) dyed with a nontoxic food coloring (Brilliant Blue FCF) and undyed as negative controls, a dyed positive control (fondant), and a dyed consumption control (Crayola Model Magic Clay) in 44 honey bee colonies. Using spectrophotometry and visual inspection, we analyzed adult bee guts, larval guts, bee bread stores and colony debris underneath the hive for presence of the dye. Our data suggest that (1) a proportion of adult bees ingest the patty, (2) adult bees likely do not feed patty directly to larvae, (3) adult bees do not store patty like bee bread, and (4) only a very small proportion of patty is lost as debris. Collectively our data suggest that honey bee colonies use pollen substitute patties. However, patties likely do not replace the function of natural pollen entirely in terms of larval provisioning and long-term storage as bee bread.

Worldwide, there is increasing evidence that shows a decline in pollinators, limiting crop pollination and production. However, it is unclear to what extent Chinese agriculture could be impacted by pollinator deficits. Data for 84 major crops in China between 1961 and 2018 were analyzed for the temporal trends in crop area and production, agricultural economic contribution of pollination, crop yield deficits, and honey bee pollination demand. We found a rapid increase in agricultural dependence on insect pollinators: both the cultivated area and total production of pollinator-dependent crops increased faster than those of pollinator-independent crops during 1961–2018.The total economic value of pollination amounted to US$ 106.08 billion in 2010, representing 19.12% of the total production value of Chinese agriculture, approximately twice the 9.5% value estimated for global agriculture. Crops with higher pollinator dependence showed greater mean growth in cultivated area than those with lower dependence, but lower mean growth of crop production and yield. Crop yield growth was also more unstable with increasing pollinator dependence. The minimum pollination demand for honey bee colonies was about three times the stock of honey bee colonies available in 2018. Furthermore, we found a decline in crop yield deficit with the increase in honey bee colony pollination service capacity. We considered that the shortage of pollinators resulted in the yield deficits for pollinator-dependent crops. Future increase in the area of pollinator-dependent crops will increase the need for more pollinators, suggesting the importance of implementing measures to protect pollinators to ensure a better-secured future for agricultural production in China.

Pollinator-dependent crops rely on the activity of managed and wild pollinators. While farm management and surrounding landscape can influence wild pollinator contributions, managed pollinator contributions may be primarily driven by their stocking densities, though this is not well studied across crops. We selected 20 southern highbush blueberry farms along two independent gradients of honey bee Apis mellifera L. (Hymenoptera: Apidae) stocking density (∼1–11 hives/acre) and bumble bee Bombus impatiens Cresson (Hymenoptera: Apidae) stocking density (0 - 3 colonies/acre) ensuring that stocking densities were not correlated with farm or landscape attributes. Across farms, we observed managed and wild bee visitation rates, and measured yield estimates. Farms with greater bumble bee stocking densities had higher bumble bee visitation rates and yield estimates, but farms with higher honey bee stocking densities only received higher honey bee visitation rates at the end of bloom and did not have higher yield estimates. The main wild pollinator, the southeastern blueberry bee Habropoda laboriosa (Fabricius) (Hymenoptera: Apidae), showed higher visitation rates on organic farms and in late bloom. In general, higher visitation rates by honey bees, bumble bees, and H. laboriosa were correlated with higher yields. Our results suggest that yields are limited by bee visitation rates, and that within the stocking density ranges studied, increasing managed bumble bees, but not honey bees, increases their visitation rates. While H. laboriosa had the greatest effect on yield estimates, its activity appears to be limited by both a phenological mismatch with crop bloom and farm management.

Grapevine leafroll disease is a significant concern in the wine grape industry, as it spreads rapidly and contributes to economically significant reductions in yield and grape quality. Our objective was to utilize 5 yr of grower-sourced data from Napa (California, USA) to improve local and regional disease management efforts. Specifically, we applied a spatially integrated multivariate clustering technique to improve understanding of spatiotemporal trends in Pseudococcus maritimus (Ehrhorn) male populations—the primary vector in the region. We also implemented generalized linear mixed models to evaluate the effects of two key practices, insecticide sprays and roguing, on disease incidence. Results show P. maritimus has a biannual flight pattern in the study area, with the first flight peaking in early May and the second between early August and early September. Clusters of P. maritimus flight data fall largely within the vineyard footprints of individual growers, but also showed clear neighborhood effects. We found that when disease incidence within a block is <1%, consistent monitoring and removal of diseased vines is required to contain within-block spread. As within-block disease incidence grows to 1–20%, both insecticide applications and roguing are effective practices to reduce spread. At incidence levels >20%, roguing is a critical practice. Our results emphasize the importance of individual management efforts, but also the value of programs that engage the wider neighboring community and highlight the power of community data collection to guide decision-making.

Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease, which affects wine grapes and leads to reduced crop yield and quality. The pathogen-plant-vector relationship of GRBV is not well understood; however, some possible vectors have been identified: Caladonus coquilletti (Van Duzee; Hemiptera: Cicadellidae), Colladonus reductus (Van Duzee; Hemiptera: Cicadellidae), Erythroneura spp., Melanoliarus sp. (Hemiptera: Cixiidae), Osbornellus borealis DeLong. & Mohr (Hemiptera: Cicadellidae), Scaphytopius granticus (Ball; Hemiptera: Cicadellidae), Spissistilus festinus (Say). Of these species, S. festinus has been shown to transmit the virus to uninfected grapevines, making it of particular interest. Since the pathogen-plant-vector relationship of GRBV is not yet completely understood, pesticide use is not necessarily the best way to manage these possible vectors. Here we test if ground cover removal, by discing in spring, could reduce the activity of potential GRBV vectors. We show that S. festinus presence in the canopy was reduced in disc rows compared to just mowing the ground vegetation, whereas there were no differences in presence in the canopy between disc and mow rows of the other possible insect vectors. Erythroneura elegantula (Osborn; Hemiptera: Cicadellidae), a common pest of grapevines but not a candidate GRBV vector, was found to have higher densities in the canopy in disc rows compared to mow rows, an effect possibly mediated by changes in vine vigor associated with ground covers. We conclude that if S. festinus is a primary vector of GRBV, discing ground covers in early spring may be a viable way to reduce their presence in the vine canopy.

Climate change-induced salinity intrusion into agricultural soils is known to negatively impact crop production and food security. However, the effects of salinity increase on plant–herbivore–natural enemy systems and repercussions for pest suppression services are largely unknown. Here, we examine the effects of increased salinity on communities of rice (Oryza sativa), brown planthopper (BPH), Nilaparvata lugens, and green mirid bug (GMB), Cyrtorhinus lividipennis, under greenhouse conditions. We found that elevated salinity significantly suppressed the growth of two rice cultivars. Meanwhile, BPH population size also generally decreased due to poor host plant quality induced by elevated salinity.The highest BPH density occurred at 2.0 dS/m salinity and declined thereafter with increasing salinity, irrespective of rice cultivar.The highest population density of GMB also occurred under control conditions and decreased significantly with increasing salinity. Higher salinity directly affected the rice crop by reducing plant quality measured with reference to biomass production and plant height, whereas inducing population developmental asynchrony between BPH and GMB observed at 2 dS/m salinity and potentially uncoupling prey–predator dynamics. Our results suggest that increased salinity has harmful effects on plants, herbivores, natural enemies, as well as plant–pest–predator interactions.The effects measured here suggest that the bottom-up effects of predatory insects on rice pests will likely decline in rice produced in coastal areas where salinity intrusion is common. Our findings indicate that elevated salinity influences tritrophic interactions in rice production landscapes, and further research should address resilient rice insect pest management combining multipests and predators in a changing environment.

In blueberry crops, there are multiple pest species, and some of those can be suppressed by natural enemies including parasitoid wasps and predators. Parasitoid wasps occur within the environment often tracking pest species for food resources to complete their lifecycle.These small wasps are also sensitive to agricultural environments including agrichemicals, habitat availability, and climate. We investigated how the structure of parasitoid communities varied between organic and conventional blueberry systems, and how the communities of these parasitoids varied within field spatial scales (forested border vs edge vs interior). With the lower intensity of agricultural interventions occurring in organic systems and forested borders, we predicted more stable parasitoid numbers that would be insulated from predicted climate variability. In our study, parasitoids were observed in low abundance in each cropping system, with community structure dependent on both management practice and field position. Unmanaged blueberry fields and forested field borders contained more parasitoid families, and in conventional systems, we saw fewer families present in the field interior as compared to field borders. In this first study to characterize Southern parasitoid communities in blueberry production systems, we observed over 50 genera of parasitoids, with a few dominant families (Braconidae and Ichneumonidae) that would contribute to biological control in blueberry systems. Overall, we captured few parasitoids, which indicates a potential vulnerability in biological control, and the need for further research using other sampling techniques to better understand these parasitoid communities.

The khapra beetle, Trogoderma granarium, is an important quarantine pest of stored-products. While it is not established in the North America, frequent interceptions highlight the need for treatments to eradicate isolated populations if they occur. Methyl bromide has long been the standard fumigant used for this purpose; however, increasing restrictions on its use necessitate the development of new treatment options. Here we evaluate a treatment for khapra beetle using a combination of sulfuryl fluoride (SF) and propylene oxide (PPO). Experiments were conducted to determine the most tolerant stages and the effective rates for each compound. Combination treatments using both products were then evaluated at several temperatures to determine effective doses for quarantine level control. The egg stage was by far the most tolerant to SF, requiring concentration × time (CT) products roughly 10-fold greater than the next most tolerant stage, diapausing larvae. Diapausing larvae were significantly more tolerant to SF than non-diapausing larvae in a recently collected ‘field' strain, but not in a more than 30-yr-old ‘laboratory’ culture. PPO treatments were shown to completely control the egg stage at CTs greater than 155 hr-mgL^-1 at both 10 and 20°C. Resulting combination treatments with initial dose rates of 96 and 40 mgL^-1 at 10°C and 80 and 40 mgL^-1 at 20°C are proposed for SF and PPO, respectively.These combination treatments utilize SF's efficacy against the larval stage along with PPO's superior ovicidal properties to provide enhanced treatment efficacy over each product alone against all life stages of khapra beetle.

To ascertain the direct effects of water stress upon wheat plants (Triticum aestivum L.) and how these effects, in turn, influence the population growth of the bird cherry-oat aphid (Rhopalosiphum padi L.), we conducted a physiological analysis of wheat seedlings grown under three different watering regimes and subsequently determined the population parameters of the aphid using the age-stage, two-sex life table. A significantly higher content of free amino acids and soluble sugars were observed in wheat seedlings exposed to drought stress compared to seedlings that were well-watered and those that were grown under waterlogged conditions. Extended phloem salivation and stylet penetration with shorter duration of sustained ingestion from phloem was observed in an electrical penetration graph (EPG) of R. padi on drought-stressed wheat seedlings. This suggested that the aphid's feeding activity, as well as nutrient intake, were impeded. The significantly higher percentage of essential amino acids found in wheat seedlings grown under waterlogged conditions promoted significantly higher fecundity and intrinsic rate of increase in R. padi populations compared to aphids fed on drought-treated or well-watered wheat seedlings. Our findings suggest that wheat seedling responses to water stress involve changes in sap composition that are responsible for altering the aphids' nutrient intake and consequently affect their population growth. From a grower's perspective, extending wheat cultivation in a rice–wheat rotation paddy field during the winter season may not be economically profitable if the fields are chronically waterlogged, since this may potentially lead to a higher infestation of cereal aphids.

Odorant-binding proteins (OBPs) capture and transport semiochemicals to olfactory receptors (OR) and function in the first step in insect olfaction. In the present study, we cloned a full-length cDNA sequence of BodoOBP5 from the insect pest Bradysia odoriphaga (Diptera: Sciaridae). Real-time PCR (qRT-PCR) analysis revealed that BodoOBP5 was expressed at higher levels in female adults than in other developmental stages. In the different tissues, BodoOBP5 was highly expressed in the female antennae, whereas low levels were expressed in the head and the male antennae, expression was negligible in other tissues. The recombinant protein of BodoOBP5 was successfully expressed with a bacterial system. Competitive binding assays with nine host plant volatiles and a putative sex pheromone revealed that purified BodoOBP5 strongly bound to two sulfur compounds (methyl allyl disulfide and diallyl disulfide); the corresponding dissolution constants (Ki) were 10.38 and 9.23 µM, respectively. Molecular docking indicated that Leu99, Leu103, Ala143,Tyr107, Phe142, andTrp144 in the hydrophobic cavity of BodoOBP5 are the key residues mediating the interaction of BodoOBP5 with methyl allyl disulfide and diallyl disulfide. RNAi-basedY-tube olfactometer assay indicated that there is no significant difference in methyl allyl disulfide and diallyl disulfide.The results of this study increase our understanding of the binding of BodoOBP5 with plant volatiles, facilitating the development of novel ways to control B. odoriphaga.

Flexibility in oviposition site selection under temporally shifting environmental conditions is an important trait that allows many polyphagous insects to flourish. Population density has been shown to affect egg-laying and offspring fitness throughout the animal kingdom. The effects of population density in insects have been suggested to be mutualistic at low densities, whereas intraspecific competition is exhibited at high densities. Here, we explore the effects of adult crowding and spatial resource variation on oviposition rate in the invasive pest Drosophila suzukii (Matsumura). In a series of laboratory experiments, we varied the density of adult males and females while holding oviposition substrate availability constant and measured per female oviposition rate using high and low-quality substrates. We found that oviposition behavior was affected more by substrate than adult density, though both variables had significant effects. When we varied the spatial arrangement of whole raspberries, we observed differences in oviposition rate and egg distribution between the grouped and solitary female treatments. Our results suggest that social interactions encourage oviposition, especially when exposed to unfamiliar or unnatural substrates. These results highlight the compensating effect of increased oviposition rate per female as adult populations decline. They will help researchers and crop managers better understand in-field population dynamics throughout the season as population densities change.

Orius strigicollis (Poppius) has been commonly released to control minute pests due to its remarkable foraging and predation ability. Despite decades long history of mass-rearing using eggs of Cadra cautella Walker (Lepidoptera: Pyralidae) as food, the cost of this food impeded the predator's marketing potential. Finding cost-effective artificial diets for mass rearing programs is, therefore, the key to promote the use of this generalist predator in practice.The aim of this study was to explore suitability of alternative diets for mass rearing of this predator, using the age-stage, two-sex life table. Eight recipes of artificial diets were initially screened, and the candidate diets were subsequently evaluated using the population parameters of O. strigicollis.The highest intrinsic rate of increase was found in the O. strigicollis fed on the meridic combined Diet 1, where nymphs and adults were fed different diets. However, the intensive period of oviposition by females reared on oligidic Diet O3 contributed to the shorter rearing period (42 d) and lower rearing cost than that on combined Diet 1 (60 d). Besides, with the harvest rate of 0.919, the minimal population size of 10,774 individuals with a stable age-stage distribution was needed for daily harvesting 1,000 third instars of O. strigicollis reared on Diet O3 at the rearing cost of 0.295 NTD (newTaiwanese dollar) per nymph.Thus, Diet O3 was determined to be the most cost-effective recipe for the mass-rearing of O. strigicollis among those used in this study.

Monitoring adult populations of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a major agricultural pest, provides data useful for its control. Food attractants, considered as adult insect behavior regulators based on the preference of an herbivorous pest for food sources or their volatiles, also have great potential for monitoring populations. To study the feasibility of monitoring the population dynamics and reproductive development of H. armigera in the field using food attractants, we quantitatively analyzed reproductive organ development of adults in a laboratory population as a way to predict the reproductive development of adults trapped using food attractants in the field in 2019 and 2020. The adults trapped using food attractants had obvious generational changes and the same trends in variation for females and males. The extent of ovarian development in trapped females tended to increase within each generation, and the major axis length of testis in trapped males tended to decrease. Reproductive developmental status of trapped adults also differed significantly among months. This study shows that by trapping H. armigera with food attractants, the population dynamics of adults in the field can be monitored, and reproductive anatomy can also be used to monitor adult reproductive status. These approaches are a new way to forecast the population dynamics of this pest.

Navel orangeworm (Pyralidae: Amyelois transitella) is a key pest of almonds and pistachios in California. Moths directly infest nuts which leads to reduced crop yield and quality, and infestation can predispose nuts to fungal pathogens that produce aflatoxins. While several integrated pest management strategies have been developed for A. transitella, studies have recently been initiated to explore the use of sterile insect technique (SIT) as an additional control tool. Mass-rearing, sterilization, and transportation methods originally developed for Pectinophora gossypiella (Lepidoptera: Gelechiidae) are currently being used for production of A. transitella in a mass-rearing facility, but the impacts of these processes on performance of A. transitella remain unclear. In this study, computerized flight mills were used to evaluate multiple flight parameters of mass-reared and irradiated A. transitella males and females relative to non-irradiated mass-reared moths and two strains of locally reared moths which were neither mass-reared nor irradiated. Mass-reared non-irradiated females performed similarly to both strains of locally reared females, flying a mean 9.4–11.8 km per night, whereas mass-reared and irradiated males and mass-reared non-irradiated males all flew shorter distances, in the range of 3.0–6.7 km per night. All of the mass-reared moths compared to locally reared moths had significantly more non-fliers that did not engage in more than two minutes of continuous flight. Findings from this study suggest that mass-rearing conditions reduce A. transitella flight capacity, while irradiation interacts with moths in a sex-specific manner.

The ectoparasitoid beetle, Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae), has been widely used as a biological control agent for many cerambycid beetles in China, Korea, and Japan. However, much less is known about its phototactic behavior to visual stimuli. In this paper, the phototactic behavioral response of D. helophoroides to 27 monochromatic lights and to nine illumination intensities of the most attractive light was evaluated using light-emitting diodes (LEDs) as light sources. The results showed that in dual choice between darkness and individual LED light, D. helophoroides adults exhibited a positively phototactic response to all wavelengths ranging from 300 to 860 nm. The near-infrared light (NIR, ranging from 700 to 760 nm) elicited stronger phototactic behavioral response, showing a preference for NIR wavelengths light. In paired choice among four preferred NIR lights, D. helophoroides adults displayed a significantly more favorable response to NIR light at 700 nm. Furthermore, the beetles expressed varying levels of sensitivity to illumination intensities from 1 to 600 lux under NIR light at 700 nm. The phototactic response was strongest at 7 lux and a statistically significant downward trend was found with increasing or decreasing the illumination intensities. These findings clearly demonstrate that D. helophoroides is a positively phototactic insect and its phototactic behavior is significantly influenced by light wavelength and illumination intensity, among which NIR light with peak wavelength at 700 nm and an intensity at 7 lux are most suitable in attracting D. helophoroides adults.

Since the mid-19th century, grasshoppers have posed a substantial threat to North American rangelands as well as adjacent croplands and have the potential to cost the economy millions of dollars in annual damages. The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) have gone to great lengths to ensure that rangeland grasshopper populations remain below an economic impact threshold across the western United States. However, current grasshopper forecasting efforts by the USDA are based solely on the previous year's grasshopper density and do not take region-specific environmental factors (e.g., climate and topography) into account.To better understand the effects of climate and landscape heterogeneity on rangeland grasshopper populations, we assessed the relationship between grasshopper density survey data from across 56 sites between 2007 and 2017 for four counties in north central Wyoming with 72 biologically relevant geographic information system (GIS)-based environmental variables. A regression model was developed to predict mean adult grasshopper density from 2012 to 2016, which was then used to forecast grasshopper density in 2017. The best-fit predictive model selected using Akaike's Information Criterion (AICc) explained 34.5% of the variation in mean grasshopper density from 2012 to 2016. October precipitation and past mean grasshopper density from 2007 to 2011 were among the best predictors of mean grasshopper density in 2012–2016. Our results also suggest that rangelands in central Sheridan County, southwest Johnson County, and southeast Washakie County are more prone to grasshopper outbreaks. Most importantly, this study demonstrated that both biotic and abiotic environmental variables influence grasshopper density and should be considered in future forecasting efforts.

Many damaging agricultural pests can, in addition to their direct feeding damage, acquire and transmit plant pathogens. Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is considered a ‘supervector’ of disease-causing plant pathogens and viruses. One of the most damaging of these is Tomato yellow leaf curl virus (TYLCV), a circulatively transmitted begomovirus than can extensively damage field and greenhouse crops. Because sustained feeding periods are necessary to acquire and transmit circulatively transmitted viruses, pesticides that, in addition to their direct lethality, suppress feeding in surviving individuals may be particularly effective in decreasing viral transmission. We assessed the impact of sulfoxaflor, a sulfoximine insecticide, on the settling preference, feeding, and viral transmission of TYLCV-carrying B. tabaci on tomato. We found that viruliferous B. tabaci avoided both settling and feeding on sulfoxaflor-treated plants, and that sulfoxaflor virtually eliminated the transmission ofTYLCV by B. tabaci.The antifeedant properties of sulfoxaflor have previously been reported in other pest systems; our results document similar effects on viruliferous B. tabaci and demonstrate that this pesticide can reduceTYLCV transmission by surviving individuals.

Exposure to sublethal amounts of pesticide can compromise life-history traits and behavior of natural enemies thereby reducing their effectiveness as predators. However, sublethal exposures to pesticides and other stressors may also stimulate insects, a dose–response phenomenon known as hormesis. We previously reported stimulatory effects on reproduction in the beneficial insect predator Podisus maculiventris (Say) (Hemiptera: Pentatomidae) following exposure to sublethal concentrations of imidacloprid. Here we examined whether these same treatments stimulated behavior and/or predation of P. maculiventris. Stimulation of some behaviors occurred at a reproductively hormetic concentration and two additional sublethal concentrations, depending upon bioassay design and sex. We observed no substantial inhibition of behavior or predation at a reproductively hormetic concentration, demonstrating that reproductive fitness in P. maculiventris may be stimulated without compromising behaviors important in its effectiveness as a natural enemy.

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is one of the most important pests in tropical and subtropical regions of American. S. frugiperda was first detected in Southern China in January 2019, and then subsequently invaded in 26 provinces. Spinetoram widely used for pest management is recommended for S. frugiperda control. The sublethal effects of spinetoram on S. frugiperda were investigated in the present study.The toxicity of spinetoram against S. frugiperda larvae was determined after one oral dose of spinetoram at sublethal concentration.The results showed that spinetoram LC₁₀ and LC₃₀ were 0.011 and 0.044 mg/liter for the larvae, respectively. Spinetoram at sublethal concentration significantly increased developmental time but reduced larval body weight. In addition, spinetoram had a post-exposure effect on pupal weight, but not on pupal duration, pupation rate, emergence rate, eggs number, or adults longevity. In conclusion, the sublethal effects of spinetoram could negatively affect the growth and development of S. frugiperda that have important implications for pest management.

Psix saccharicola (Mani) and Trissolcus semistriatus (Nees) are the most abundant eggs parasitoids of the stink bug, Acrosternum arabicum Wagner, in pistachio orchards and have the potential to contribute to their suppression. However, treatment of orchards with broad-spectrum insecticides may greatly reduce populations of these beneficial natural enemies. Therefore, we conducted risk assessments and evaluated sublethal impacts of two insecticides routinely used in pistachio orchards: the organophosphate fenitrothion and a formulated mixture of the neonicotinoid thiamethoxam and the pyrethroid lambda-cyhalothrin on parasitism success, emergence and sex ratio of P. saccharicola andT. semistriatus. Based on the values of their risk quotients (RQ), which are derived from toxicity data, the two insecticide products would be classified as slightly-to-moderately toxic although an alternative metric, the safety factor (SF), showed them to be highly risky. Assessments of sublethal effects on adult wasps showed that insecticide exposure significantly reduced their ability to successfully parasitize stink bug eggs, and exposure of adult females reduced the emergence, survival, and proportion of females of their progeny, which could disrupt biological control for an extended period of time. Analysis of the decreased emergence and parasitism for P. saccharicola and T. semistriatus in accordance with the standards of the International Organization for Biological Control (IOBC) indicate that fenitrothion is slightly harmful to both parasitoid species whereas the mixture of thiamethoxam + lambda-cyhalothrin is moderately harmful. These findings will be useful for integrating insecticides and egg parasitoids into a comprehensive integrated pest management program for managing stink bugs populations in pistachio orchards.

Pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), can reduce the yield of field pea [Pisum sativum (L.) (Fabales: Fabaceae)] and faba bean [Vicia faba (L.) (Fabales: Fabaceae)]. Adults feed on the foliage and larvae feed on root nodules and nodule-associated Rhizobium Frank (Rhizobiales: Rhizobiacea) bacteria. In this study, we developed a data-based nominal threshold for pea leaf weevil in faba bean. We further tested the efficacy of insecticidal seed treatment and foliar insecticide (thiamethoxam and lambda-cyhalothrin, respectively), and nitrogen amendment for pea leaf weevil control using a multi-year field plot study at two sites in Alberta, Canada. Pea leaf weevil feeding damage significantly reduced faba bean yields. Thiamethoxam reduced adult and larval damage, and protected faba bean yield, while neither lambda-cyhalothrin nor a nitrogen amendment was effective in protecting yield.The percentage of seedlings with feeding on the terminal leaf had a negative relationship with yield and was used to estimate a nominal threshold near 15% of seedlings with terminal leaf damage. Since lambda-cyhalothrin is not effective in managing pea leaf weevil on faba bean, there is a need to research additional integrated pest management strategies to reduce prophylactic insecticidal seed treatments.

Brown stink bug, Euschistus servus (Say) (Hemiptera: Pentatomidae), is a common insect that can infest corn fields in the Mid-South and Southeastern U.S. Infestations and damage are sporadic, thus little research has been conducted on the impact of brown stink bug infesting corn seedlings. Two experiments were conducted in eleven commercial corn fields in the Mississippi Delta to evaluate the impact of damage from natural stink bug infestations during the seedling stage (<V4) on corn yield and growth during 2018 and 2019. Single plants and 3-meter sections of the row were marked at each location. Plant damage for the single plant experiment was rated on a 0–3 scale and every single plant was given a damage rating based on visible symptomology. As damage severity increased, plant height and yield decreased. Some plants with the most severe damage did not produce any grain. At each location, sections of row (plots) with 0%, 10%, 20%, 30%, or 40% damaged plants were identified. All levels of damaged plants resulted in lower yield compared to the nondamaged control. These results demonstrate the brown stink bug infestations during the seedling stage (<V4) can reduce corn yield. The magnitude of yield reductions can be dependent on several factors including the severity of damage to individual plants and the percentage of plants with damage within the field. Although detecting infestations with current scouting methods is difficult, fields should be scouted and infestations managed to minimize yield loss.

Following the detection of fall armyworm Spodoptera frugiperda (J.E. Smith, Lepidoptera: Noctuidae) in Western Australia in early 2020 and the lack of government response action, we estimate the impact it is likely to have on the state's agriculture. A bioeconomic model is used to estimate cost and revenue implications for broadacre cropping and horticulture industries. We assume permanent S. frugiperda populations are likely to establish in areas of the state's north and mid-west over the next decade, and other regions may experience sporadic outbreaks over single seasons. Over 0.8 million hectares of host crops could be permanently affected, while sporadic outbreaks may affect a further 150,000 hectares. Expressed in Australian dollars (A$), S. frugiperda is likely to add a A$14.2–39.3 million burden to agricultural producers per annum by year 10 of the outbreak. Approximately 55% of these damage costs are attributable to yield loss and 45% to increased variable production costs.

The wool of the invasive, non-native hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), occurs mostly on hemlock (Tsuga sp.) twigs, but can be dislodged from the canopy and end up on the forest floor and tree stem underneath the canopy. Herein, we developed and tested the efficacy of two novel sampling techniques, which are based on a visual examination of the forest floor and the hemlock stem for A. tsugae wool. Subsequently, we compared these two techniques to a visual examination of foliage and ball sampling which are two methods currently used operationally. We sampled 11 hemlock stands, with low to moderate incidence A. tsugae populations, near Ithaca, New York in 2016 and assessed the probability of detecting wool on a tree and in a stand, as well as the relative variation and relative net precision for each of the four techniques. We found that sampling the tree stem outperformed foliage and ground sampling, likely because of its higher detection rate and lower relative variation, but not ball sampling. Our findings suggest that combining stem, ball and ground sampling was the most effective combination of techniques and gave a high probability of detecting an infested tree or an infested stand. All techniques were an improvement over foliage sampling, even after increasing the foliage sampling effort fivefold.

The microlepidoptera, Bedellia somnulentella (Zeller), is an important pest of sweetpotato, Ipomoea batatas (L.) Lam. Damage by B. somnulentella occurs in the larval stage and when consuming the foliar mesophyll of I. batatas make the leaves brown, wrinkled, and reducing the photosynthetic area and the yield.The detection and management of this pest depends on knowing its biological cycle and identifying its natural enemies.The objectives of this study were to determine the life history of B. somnulentella feeding on I. batatas leaves and to survey parasitoids of this pest in the field.The duration and viability of B. somnulentella egg, larva, prepupa, pupa, and adult stages were evaluated under laboratory conditions. Cephalic capsule width was measured to determine the number of B. somnulentella instars, based on the Dyar rule and analyzed by the Akaike statistical model (AIC). The developmental period of B. somnulentella was 32.5 ± 0. 21 d with a viability of 75, 84, 100, and 84% for the egg, larva, prepupa, and pupa stages, respectively.The identification of this pest on the plants is possible from the third instar and in the pupal and adult stages. The parasitoid Conura sp. (Hymenoptera: Chalcididae) was identified parasitizing pupae of B. somnulentella and could be considered a potential natural enemy for the integrated management of this pest.

The invasive spotted-wing drosophila, Drosophila suzukii (Matsumura), is a key insect pest of berries globally, causing lost revenues and increased production costs associated with applications of insecticides.The insecticides utilized are commonly broad-spectrum pyrethroids, organophosphates, or carbamates in conventionally managed fields and spinosad in organically managed fields. Adoption of more selective insecticides has been limited due to their lower residual activity, and the requirement that some must be ingested to be effective. We investigated the use of feeding stimulants for D. suzukii as a method to improve longevity and efficacy in a range of insecticides. In laboratory bioassays, sugar increased the efficacy of all chemical classes tested; however, the inclusion of yeast only showed a benefit with malathion. Feeding stimulants had a limited effect in some cases under field conditions. Similarly, infestation in field plots and a semifield bioassay showed no significant decreases in infestation with the inclusion of feeding stimulants for the insecticides tested in these trials. We discuss the implications of these findings for managing D. suzukii in fruit crops to help ensure the harvest of marketable fruit.

Ambrosia beetles (Xylosandrus spp.) are pests of woody ornamental nurseries and tree nut orchards. Growers use ethanol-infused bolts and ethanol-mediated bottle traps for monitoring ambrosia beetles in the spring.To refine these monitoring tools, we investigated the 1) sensitivity of the commercially available ethanol pouches placed on bolts compared with that of ethanol-infused bolts for ambrosia beetle attacks; and 2) the effect of aging of ethanol pouches on ambrosia beetle captures in bottle traps. Experiments were conducted in ornamental nurseries and pecan orchards in 2019 and 2020. For objective 1, the treatments included a bolt infused with locally purchased ethanol, an ethanol pouch attached to a bolt, and a control (bolt without ethanol). For objective 2, ethanol pouches were initially field-aged for 0, 1, 2, 3, and 4 wk and ambrosia beetle captures were documented weekly for 4 wk. Ethanol pouches older than 5 wk were replaced with fresh pouches at the pecan sites while ethanol pouches at nursery sites were aged up to 8 wk.The ethanol-pouch comparison study showed that the number of ambrosia beetle attacks was significantly greater on ethanol-infused bolt traps than with the ethanol pouches on bolts at the nursery and pecan sites in both years.The age of the ethanol pouches did not affect captures of Xylosandrus crassiusculus (Motschulsky) and X. germanus (Blandford) in bottle traps within 8 wk of deployment. Results provide practical implications into the sensitivity of the different ethanol lure types in association with bolt traps and the longevity of the ethanol pouches for grower use.

Drosophila suzukii Matsumura (Diptera: Drosophilidae), or spotted-wing drosophila, is an invasive pest first detected in the United States in 2008. Although D. suzukii can use many cultivated fruit as hosts, raspberries are considered ‘most at risk’ for infestation. Conventional broad-spectrum insecticides are proven effective D. suzukii controls and can be economically profitable when combined with integrated pest management (IPM) on large-scale commercial raspberry farms. It remains unclear, however, whether organic controls are cost-effective strategies, particularly for farms operating on a small-scale seasonal basis, as is common in the Upper Midwest. The purpose of this paper is to explore the efficacy of two organic D. suzukii controls—exclusion netting for high tunnels and organic insecticides for open plots using data available from different field trials—and to ascertain whether any economic benefits of the organic controls outweigh treatment costs for small-scale raspberry operations under different risk scenarios. The field trials suggest that the organic treatments are effective controls for D. suzukii infestation and economically profitable. The exclusion netting treatment produced positive net returns compared to the alternative of no treatment and economically outperformed the organic-certified insecticide treatment for several yield, price and infestation scenarios. As D. suzukii infestation rates increased, net returns improved for both organic treatments. The economic results were robust across a range of yields and prices, suggesting that in almost all scenarios small scale organic raspberry growers benefit economically from the application of exclusion netting on high tunnels and insecticides for open plots.

Brown marmorated stink bug, Halyomorpha halys, is native to Asia and has invaded North America and Europe inflicting serious agricultural damage to specialty and row crops. Tools to monitor the spread of H. halys include traps baited with the two-component aggregation pheromone (PHER), (3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol, and pheromone synergist, methyl (2E,4E,6Z)-decatrienoate (MDT). Here, an international team of researchers conducted trials aimed at evaluating prototype commercial lures for H. halys to establish relative attractiveness of: 1) low and high loading rates of PHER and MDT for monitoring tools and attract and kill tactics; 2) polyethylene lure delivery substrates; and 3) the inclusion of ethyl (2E,4E,6Z)-decatrieonate (EDT), a compound that enhances captures when combined with PHER in lures. In general, PHER loading rate had a greater impact on overall trap captures compared with loading of MDT, but reductions in PHER loading and accompanying lower trap captures could be offset by increasing loading of MDT. As MDT is less expensive to produce, these findings enable reduced production costs. Traps baited with lures containing PHER and EDT resulted in numerically increased captures when EDT was loaded at a high rate, but captures were not significantly greater than those traps baited with lures containing standard PHER and MDT. Experimental polyethylene vial dispensers did not outperform standard lure dispensers; trap captures were significantly lower in most cases. Ultimately, these results will enable refinement of commercially available lures for H. halys to balance attraction and sensitivity with production cost.

Queensland fruit fly (Q-fly), Bactrocera tryoni (Froggatt), presents a major threat to Australian fruit production and trade. The sterile insect technique (SIT) is increasingly employed to manage Q-fly. Quality of sterile males released in SIT programs, and hence program efficacy, can be affected by pre- and post-production processes, such as mass rearing, packing, irradiation, transportation, and release. Given long distances from rear-out facilities to release sites, adult flies are usually chilled to reduce metabolism and stress during transportation. To guide SIT procedures, it is important to understand the impact of such practices on performance of sterile Q-fly. The present study assesses the effect of chilling temperature and exposure period on quality parameters of sterile Q-fly. We considered the effects of two temperature regimes (4 and 6°C) and six exposure periods (0, 1, 2, 4, 6, and 12 h) on chill-coma recovery time, flight ability, survival under nutritional stress, and longevity of both males and females. Flies chilled at 4°C took longer to recover than that those chilled at 6°C. Flight ability, survival under nutritional stress, and longevity all decreased as chilling period increased but did not differ between the two tested temperatures. We recommend that periods of chilling during transportation from rear-out facilities to release sites be minimized in order to retain quality of sterile Q-fly and that increased release rates be considered when longer chilling periods are required.

Management of direct apple pests, such as codling moth, continues to be problematic despite the widespread implementation of behavioral and chemical controls. Apple growers have increased their use of netting to protect fruit from environmental injury, with some structures enclosing the entire orchard.These enclosures represent a new pest management tactic through physical exclusion. We conducted a two-year trial to examine the effects of full exclusion netting on pests and natural enemies of apples. Insect densities and damage in trees under fully enclosed (net) cages were compared with conventionally (insecticide only) treated and untreated plots. Caged plots had 18.1- and 11.4-fold less codling moth damage than the check, and 4.9- and 4.2-fold less damage than the insecticide-only plots in 2016 and 2017, respectively. However, densities of woolly apple aphid and its parasitoid Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) were significantly greater in the caged plots. Densities of earwigs, a typically flightless generalist predator, were not different among treatments, while adults of more mobile flying generalist predators, lacewings and syrphids, were significantly lower in cages compared with uncaged plots.These results demonstrate that although biological control may be partially disrupted, net enclosures have significant potential as a holistic apple management technique.

Managing spotted-wing drosophila, Drosophila suzukii (Matsumura), in fruit crops is complicated by the unreliability of currently available traps for monitoring adult flies, combined with the difficulty of detecting larval infestation before fruit damage is apparent. A simple method to extract larvae from fruit in liquid, strain the solution, then count them in a coffee filter was developed recently for use in integrated pest management programs. Here, we present a series of experiments conducted to improve fruit sampling by making it faster, less expensive, and more accurate. The volume of blueberries sampled (59–473 ml) did not significantly affect the detection of second and third instars, but we found that 118-ml samples were best for detecting the smallest larvae. These small instars were more detectable when berries were lightly squeezed before immersion, whereas larger instars were similarly detectable without using this step. We also found that immersing fruit for 30 min was sufficient before counting larvae, and similar numbers of larvae were found in the filter using room temperature water rather than a salt solution. The process of filtering, detection, and counting larvae took only 2–4 min per sample to process, depending on larval density. Using a microscope to count the larvae was consistently the best approach for detecting D. suzukii larvae. Based on these results, we discuss how fruit sampling can be streamlined within IPM programs, so growers and their advisors can improve control and reduce the cost of monitoring this invasive pest.

Erythritol, an artificial sweetener, has shown promise as an organic, human-safe insecticide. Recently, erythritol applications were shown to be successful at controlling pear psylla (Cacopsylla pyricola (Förster)) (Hempitera: Psyllidae), the most important pest of pear in the Pacific Northwest, USA.Twospotted spider mite (Tetranychus urticae Koch) (Trombidiformes:Tetranychidae) and pear rust mite (Epitrimerus pyri (Nalepa)) (Trombidiformes: Eriophyidae) can also be highly damaging pear pests.Their common natural enemy, Galendromus occidentalis (Nesbitt) (Mesostigmata: Phytoseiidae), can provide biological control if selective pesticides are used for managing other pests.Through a series of bioassays, we sought to determine whether erythritol could also be used for controlling either species of pest mite. We also examined whether erythritol had acute or sublethal impacts on G. occidentalis, through a variety of exposure methods. Effects examined included mortality, fecundity, prey consumption, and locomotion. We determined that a high concentration of erythritol (30%) had efficacy against both pest mite species and caused arresting behavior in twospotted spider mite. Erythritol caused little acute mortality in G. occidentalis, but did reduce fecundity and prey consumption through some exposure methods. Through motion-capture software, we determined that this is primarily due to reduced movement, likely caused by difficulty walking on residues and excessive grooming behavior. Because the predatory mite non-target effects were less acute than those for the two pest mites, we concluded that erythritol could likely be integrated into pear IPM with little or no disruption of mite biological control.

Halyomorpha halys, (the brown marmorated stink bug, BMSB), is a high-concern invasive species causing severe damage to orchards in many countries outside its native Asian range. Control options matching both effectiveness and sustainability are currently lacking. Inhibitors of chitin biosynthesis might be exploited for integrated management programs because of the overall better ecotoxicological profile in comparison with most neurotoxic insecticides used so far against BMSB. In this study, the activity of triflumuron, a benzoylphenyl urea hampering chitin biosynthesis, was tested on BMSB in laboratory and field conditions. In laboratory bioassays, the insecticide was sprayed on potted peach plants (30 cm high) and residues were aged in a glasshouse for 0, 7, 14, and 21 d. Then, third-instar bugs were placed on the plants and continuously exposed to residues. Mortality was scored after 7, 14, and 21 d exposure.Triflumuron caused significantly higher mortality on BMSB nymphs in comparison with water controls at all aging periods. Moreover, aging of residues up to 21 d did not cause any significant reduction of activity. Field experiments were also carried out in 2019 in eight pear orchards. Injuries to fruits at harvest were compared between plots where triflumuron was added to insecticide sprays against BMSB and control plots managed exactly in the same way but without any triflumuron treatment. An overall mean of 9.99 ± 1.98% stink bug injured fruits was detected in plots managed with the strategy including triflumuron, whereas 19.45 ± 3.55% of fruits were injured in plots assigned to controls.

Philaenus spumarius (Linnaeus, 1758) (Hemiptera: Aphrophoridae) is considered the main vector of Xylella fastidiosa (Wells Raju et al. 1986) (Xathomonadales: Xanthomonadaceae), agent of the Olive Quick Decline Syndrome in Southern Europe. To limit the spread of the disease, it is of primary importance to identify effective control measures against the vector. Besides chemical control, cultural practices could potentially help reducing vector activity and population density. Here, we tested the effectiveness of three different ground cover management practices in controlling vector populations in olive groves in the Abruzzo region (Central Italy). We compared tillage (two tillage operations in spring followed by two cuts in summer), frequent mowing (four cuts from spring to summer) and a control (two cuts in summer) by sampling vectors both in the ground vegetation and in the tree canopy. In late spring, after the peak of the population, tillage reduced P. spumarius density by 60%, while frequent mowing only reduced the density by 20% compared to control plots. The differences tended to disappear with time. The treatments had the same effect on the vector density in both the ground vegetation and tree canopy. The vectors were more concentrated in the ground cover at the beginning of the season while in summer both the canopy and ground vegetation had the same vector density. Our findings suggest that tillage is a viable option for the containment of P. spumarius, as frequent mowing did not achieve sufficient control efficacy.

In establishing Integrated Pest Management (IPM) plans for understudied pests, it is crucial to understand the nature of their herbivory and resulting damage. European earwig (Forficula auricularia L.; Dermaptera: Forficulidae) densities are increasing in citrus orchards in Central California. Field observations suggest that earwigs feed on young, developing citrus fruit, but this hypothesis had not been examined with formal experimentation. Forktailed bush katydid nymphs (Scudderia furcata Brunner von Wattenwyl; Orthoptera: Tettigoniidae) are well-known citrus herbivores that feed on young citrus fruit, and it is possible that earwig damage may be misdiagnosed as katydid damage. Here we report findings from two field experiments in navel oranges (Citrus sinensis (L.) Osbeck; Sapindales: Rutaceae) that together tested: (1) whether earwigs damage young citrus fruit; (2) whether the amount of damage earwigs generate differs across developmental stage or sex of adult earwigs; (3) the window of time during which fruit are most sensitive to earwig damage; (4) whether damaged fruit are retained to harvest; and (5) the resulting damage morphology caused by earwigs relative to katydids. Earwigs, particularly nymphs, chewed deep holes in young citrus fruit from 0 to 3 wk after petal fall. Fruit damaged by earwigs were retained and exhibited scars at harvest.The morphology and distribution of scars on mature fruit only subtly differed between earwigs and katydids.This study establishes that earwigs can be direct pests in mature navel orange trees by generating scars on fruit and likely contribute to fruit quality downgrades.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an Asian invasive plant-feeding insect and an emerging kiwifruit pest. Knowledge about the BMSB dynamics and damage to kiwifruit outside the bug native range is scarce. This 2-yr study was aimed at describing phenology and infestation dynamics of BMSB in green-fleshed and yellow-fleshed kiwifruits. Natural enemies were investigated as well. Field surveys were performed weekly in two sites in Northern Italy by pheromone-baited traps and visual samplings, from early Spring to mid-Autumn. All BMSB life stages were collected and kept under observation to assess occurrence of parasitoids. A sample of fruit was dissected weekly to detect BMSB feeding injuries. In 2018–2019, BMSB was found throughout the growing season with two generations per year with a large overlapping of all life stages. Pheromone-baited traps and visual samplings gave consistent results and can be both considered effective sampling methods on kiwifruit. Fruit injuries were significantly related to kiwifruit development stage, weekly captures of BMSBs by traps, and cultivar. Several BMSB egg masses were found on kiwifruit leaves. Anastatus bifasciatus Geoffroy (Hymenoptera: Eupelmidae), a native egg parasitoid with Palearctic distribution, emerged from 20.14% of eggs in 2018, but the percent parasitism dropped to 0.47% in 2019. In both years, other natural enemies were found exerting negligible pressure on BMSB populations. The determination of reliable economic thresholds for BMSB on kiwifruit is urgently needed to develop a robust and sustainable integrated pest management (IPM) strategy, and this study provides data towards that direction.

Temperature and dehydration stress are two major co-occurring environmental stressors threatening the physiology, biochemistry, and ecology of insects. As such, understanding adaptive responses to desiccation stress is critical for predicting climate change impacts, particularly its influence on insect invasions. Here, we assessed water balance and desiccation resistance of the invasive Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), and infer how eco-physiology shapes its niche. We measured basal body water and lipid content, water loss rates (WLRs), and desiccation resistance in larvae (second to fourth instars) and adults. Body -water, -lipid, and WLRs significantly varied across life stages. Second instars recorded the lowest while fourth instars exhibited the highest body water and lipid content. Adult body water and lipid content were higher than second and third instars and lower than fourth instars while proportion of body water and lipid contents were highest in adults and second larval instars respectively. Water loss rates were significantly highest in fourth-instar larvae compared to other life stages, but differences among stages were less apparent at longer exposure durations (48 h). Desiccation resistance assays showed that second instars had greatest mortality while fourth-instar larvae and adults were the most desiccation tolerant. Our results show that T. absoluta fourth-instar larvae and adults are the most resilient developmental stages and potentially contribute most to the invasion success of the pest in arid environments. Incorporation of these species-specific eco-physiological traits in predictive models can help refine invasive species potential spread under changing climates.

Argentine ants are one of the most common nuisance pest ants treated by pest management professionals (PMPs) in southern and western urban residential areas of the United States. Two new technologies (spraying with a pheromone adjuvant and using a biodegradable hydrogel bait delivery method) were used to develop a unique low-impact integrated pest management (IPM) protocol for Argentine ants in urban residential settings. The IPM protocol included a one-time perimeter spray treatment with 0.03% fipronil (mixed with a pheromone adjuvant) at the beginning of the ant season to achieve a quick knockdown. The initial spray application was followed by a biodegradable hydrogel baiting with 1% boric acid as a maintenance treatment. This low-impact IPM protocol was compared with two other conventional methods: (1) one initial fipronil application and one pyrethroid spray application for maintenance, or (2) one initial fipronil application and one essential oil insecticide spray application for maintenance. Based on Argentine ant foraging activity, the protocols were compared for their control efficacy. Insecticide use information and treatment time were also recorded and compared among different treatment protocols. Our results provided empirical data to support the effectiveness and economic feasibility of the low-impact IPM protocol for managing Argentine ants in urban residential settings.

Sticky traps are standard tools for monitoring German cockroaches (Blattella germanica L.); however, because they lack an attractant, their ability to catch cockroaches is by chance and largely dependent upon the location of placement and length of time they are left in place. Currently, highly effective and economical cockroach attractants are not available. Food-based attractants have the potential to be employed in sticky traps and enhance their effectiveness on trapping German cockroaches. We conducted laboratory and field experiments to evaluate the effectiveness of novel food-based attractants. Laboratory results showed that sticky traps containing the following attractants: apple oil, blueberry oil, orange oil, or their combination, fish oil, peanut butter, Roach lure tablet, and bacon extract had significantly higher trap catch compared to those traps that do not contain an attractant. Apple plus blueberry oil mixture and Roach lure tablet enhanced the trap catch by ≥ 103%, and bacon extract enhanced the trap catch by 92% in the field assays. Apple plus blueberry oil mixture and Roach lure tablet were the most promising attractants based on laboratory and field experiments. Apple plus blueberry oil mixture aged for 2 wk was as attractive to German cockroaches as fresh mixture.

Overexpression of a cytochrome P450 gene, CYP4G19, is known to associate with pyrethroid resistance in the German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae). In this study, we investigated the CYP4G19 expression level in 20 field-collected strains of B. germanica in Taiwan. We also examined the level of adult male susceptibility to imidacloprid, fipronil, indoxacarb, and hydramethylnon using single-diagnostic dose bioassays and their susceptibility to corresponding gel baits to determine how the CYP4G19 expression level influences the cockroach gel bait performance. Results showed that the CYP4G19 gene expression level among the field-collected German cockroach was 1.8- to 9.7-fold higher than that of the susceptible strain. It was negatively correlated (P < 0.05) with the % mortality after treatments with imidacloprid and fipronil diagnostic doses. However, no correlation was found between CYP4G19 gene expression with the % mortality after treatment with indoxacarb and hydramethylnon diagnostic doses. Indoxacarb and hydramethylnon baits showed high efficacy against the field strains with a mean mortality of 97.58 ± 1.35% and 90.95 ±1.65%, respectively. This study provided the first evidence of cross-resistance to imidacloprid and fipronil in pyrethroid-resistant German cockroaches due to overexpression of CYP4G19.

Helicoverpa zea (Boddie), a pest of cotton that also occurs in field corn, is commonly controlled through the use of foliar-applied insecticides or transgenic crops expressing Bacillus thuringiensis (Berliner) (Bt) genes. To minimize the risk of Bt resistance in pest populations, refuge systems have been implemented for sustainable agroecosystem management. Historically, structured refuge compliance among growers has been low, leading to the commercialization of seed blended refugia. To test the viability of seed blended refugia in southern U.S. field corn, field studies were conducted in Mississippi and Georgia during 2016, 2017, and 2018 growing seasons. To quantify adult H. zea emergence from structured (non-Bt corn) and seed blended refuge options, emergence traps were utilized. Kernel damage among seed blended refuge and structured refuge corn ears were recorded and compared. The timing of moth emergence was recorded. When compared to a structured refuge, H. zea adult moth emergence from seed blended refugia did not significantly differ. Kernel damage of non-Bt plants in the seed blended treatments was not significantly different than non-Bt plants in the structured refuge treatments. Moth emergence timing was not significantly delayed between the structured refuge and seed blended refuge treatments. Results of this study suggest that a seed blended refuge may provide an effective insecticide resistance management alternative for H. zea in areas where structured refuge compliance is low.

Beta-cyfluthrin, as a synthetic pyrethroid, has been widely used in cigarette manufacturing factories in China to control Lasioderma serricorne (F.) (Coleoptera: Anobiidae). In this study, spray toxicity bioassays and filter paper residual contact toxicity bioassays were conducted to investigate the beta-cyfluthrin sensitivity level of five field strains of L. serricorne collected from cigarette manufacturing factories in China. Bioassay results indicated that five field strains had developed different levels of resistance to beta-cyfluthrin with RR₅₀ of 3.51–10.20 at 2 hr after application and 4.05–49.50 at 24 hr after application in spray toxicity bioassays, and RR₅₀ of 4.74–14.47 at 2 hr exposure in filter paper residual contact bioassays. In addition, we examined CarE, GST, and CYP450 enzyme activity and content of L. serricorne adults and larvae. Enzyme-linked immunosorbent assay results suggested that there was no significant difference in GST, CYP450, and CarE content of L. serricorne adults between field strains and reference sensitive strain. Biochemical assay results indicated that CYP450 activity of L. serricorne adults and larvae of five field strains was significantly higher than that of reference sensitive strain, with increased CYP450 activity of 1.08–1.82-fold in adults and 1.08–2.12-fold in larvae. The results implied that elevated CYP450 activity may contribute to metabolic resistance of L. serricorne to pyrethroid. Our study indicated that there was no clear evidence that the enhanced CarE and GST activity was associated with pyrethroid resistance of L. serricorne.

Pyrethroid insecticides have been widely utilized for insect pest control. Target-site resistance is one of the major mechanisms explaining pest resistance to pyrethroids. This study quantified pyrethroid resistance and fitness cost conferred by the voltage-gated sodium channel (VGSC) M918L mutation in Rhopalosiphum padi. Six s-kdr-SS and six s-kdr-RS parthenogenetic lineages were established from the same field population and were reared in the laboratory without exposure to pesticides for more than one year. Enzyme activity analysis demonstrated that metabolic resistance had no impact on these lineages. Bioassays showed that the M918L mutation strongly affected pyrethroid efficiency, conferring moderate resistance to bifenthrin (type I) (39.0-fold) and high resistance to lambda-cyhalothrin (type II) (194.7-fold). Compared with the life table of s-kdr-SS lineages, s-kdr-RS lineages exhibited a relative fitness cost with significant decreases in longevity and fecundity. Meanwhile, competitive fitness was measured by blending various ratios of s-kdr-SS and s-kdr-SS aphids. The results indicated that M918L-mediated resistance showed a significant fitness cost in the presence of wild aphids without insecticide pressure. The fitness cost strongly correlated with the initial resistance allele frequency. This work characterized the novel s-kdr M918L mutation in R. padi, defined its function in resistance to different types of pyrethroids, and documented that the M918L-mediated resistance has a significant fitness cost.

Three molecular protocols using qPCR TaqMan probe, SYBR Green, and loop-mediated isothermal amplification (LAMP) methods were set up for the identification of larvae and adults of an African invasive moth, Thaumatotibia leucotreta (Meyrick, 1913) (Lepidoptera: Tortricidae). The DNA extracts from larval and adult samples of T. leucotreta were perfectly amplified with an average Ct value of 19.47 ± 2.63. All assays were demonstrated to be inclusive for T. leucotreta and exclusive for the nontarget species tested; the absence of false positives for nontarget species showed a 100% of diagnostic specificity and diagnostic sensitivity for all assays. With the SYBR Green protocol, the Cq values were only considered for values less than 22 (cutoff value) to prevent false-positive results caused by the late amplification of nonspecific amplicons.The limit of detection (LoD) for the qPCR probe protocol was equal to 0.02 pg/µl while a value equal to 0.128 pg/µl for the qPCR SYBR Green assay and LAMP method were established, respectively.The intrarun variabilities of reproducibility and repeatability in all the assays evaluated as CV%, ranged between 0.21 and 6.14, and between 0.33 and 9.52, respectively; the LAMP values were slightly higher than other assays, indicating a very low interrun variability. In order for an operator to choose the most desirable method, several parameters were considered and discussed. For future development of these assays, it is possible to hypothesize the setup of a diagnostic kit including all the three methods combined, to empower the test reliability and robustness.

High population density (crowding) becomes a stress factor in insects. The oriental armyworm, Mythimna separata (Walker), displays gregarious and solitary phases at high and low population densities, respectively. In this study, we compared life history, disease resistance, and induction of antioxidant enzymes and heat shock protein (HSPs) in two phases of M. separata larvae. Results showed that gregarious larvae had a faster growth rate and lower pupal weight compared to solitary larvae. Furthermore, gregarious individuals exhibited higher survival rates than solitary individuals after Beauveria bassiana infection.The gregarious larvae had higher malondialdehyde content compared to solitary ones, but no differences in total antioxidant capacity were observed between the two larval phases before or after infection. Superoxide dismutase and glutathione peroxidase activities were significantly lower in gregarious M. separata larvae than solitary individuals before infection, but no difference was detected in two phases after infection. However, peroxidase and catalase activities in the two phases showed no difference either before or after infection. Hsp19.8 and Hsp90 expression in gregarious larvae were up-regulated when compared to solitary individuals before or after infection. CuZnSOD expression was not different between the two phases before infection, but it was up-regulated in gregarious ones compared to solitary ones after infection. However, expression of other stress-related genes in gregarious larvae was either repressed or unchanged when compared to solitary individuals before or after infection. Thus, larval crowding changed life history, improved disease resistance of M. separata larvae, and induced variable response of antioxidant enzymes and HSPs to fungal infection.

Like conventional crops, transgenic plants expressing insecticidal toxins from Bacillus thuringiensis (Bt) are subjected to water deprivation. However, the effects of water deprivation over the insecticidal activity of Bt plants are not well understood. We submitted Bt maize and Bt soybean to water deprivation and evaluated biochemical stress markers and the insecticidal activity of plants against target insects. Bt maize (DAS-Ø15Ø7-1 × MON-89Ø34-3 × MON-ØØ6Ø3–6 × SYN-IR162-4) containing the PowerCore Ultra traits, Bt soybean (DAS-444Ø6-6 × DAS-81419-2) with the Conkesta E3 traits, and commercial non-Bt cultivars were cultivated and exposed to water deprivation in the greenhouse. Leaves were harvested for quantification of hydrogen peroxide, malondialdeyde (MDA), and total phenolics and insecticidal activity. Maize or soybean leaf disks were used to evaluate the insecticidal activity against, respectively, Spodoptera frugiperda (J.E Smith) and Chrysodeixis includens (Walker) neonates. Except for Bt soybean, water deprivation increased hydrogen peroxide and MDA contents in Bt and non-Bt plants. Both biochemical markers of water deficit were observed in lower concentrations in Bt plants than in non-Bt commercial cultivars. Water deprivation did not result in changes of phenolic contents in Bt and non-Bt maize. For Bt or non-Bt soybean, phenolic contents were similar despite plants being exposed or not to water deprivation. Water deprivation did not alter substantially insect survival in non-Bt maize or non-Bt soybean. Despite water deprivation-induced biochemical changes in plants, both Bt plants maintained their insecticidal activity (100% mortality) against the target species.

Catfacing and gummosis/sap-type injury associated with a heteropteran pest complex were sampled at five peach orchards in southern Florida during two consecutive growing seasons. Trapping and visual surveys indicate that Euschistus servuis (Say) (Hemiptera: Pentatomidae) was the dominant heteropteran pest in the study orchards.The spatial arrangement of injury indicated a random distribution, as determined byTaylor's power law. Spatial analysis by distance indices indicated a random arrangement of fruit injury in a majority of the sample site × date combinations and analysis of local clustering did not provide evidence of patches of fruit injury occurring near orchard borders. The coefficients from Taylor's power law were used to develop sequential sampling plans based on hypothetical injury thresholds. Sequential sampling plans were compared to a simple random sample of 15 sample units using a simulation approach. The sequential sampling plan was able to achieve equivalent levels of accuracy when compared to the 15-unit fixed sampling plan while reducing the number of sample units required to an average of 7.99. The sequential sampling plans developed in this study are an improvement over simple random sampling; however, further research is needed to determine how to best implement sequential sampling of fruit injury in Florida peach orchards to better inform management decisions.

Optimization of integrated pest management for Pacific spider mite, Tetranychus pacificus McGregor, in California almonds requires that miticide applications be delayed as long as possible to promote biological control, while still occurring before exponential mite increases cause defoliation. We used data from twelve untreated almond orchards between 2006 and 2019 to determine that decisions to treat T. pacificus should be made on the first monitoring date with 1.4 mites per leaf (38.1% of leaves infested) to ensure that miticide applications are made prior to reaching the treatment threshold of 5.4 per leaf an average of 4.7 d later. Modifications to this threshold based on biological control were made using capture rates of sixspotted thrips, Scolothrips sexmaculatus Pergande, on yellow adhesive traps from 14 almond orchards between 2016 and 2019. Data showed that T. pacificus density remained unchanged when there were 0.42 S. sexmaculatus per trap per week for every one T. pacificus per leaf. For orchards where T. pacificus density has exceeded action and treatment thresholds, we developed a less accurate, but more practical, model that does not require counting mites on leaves. On average, T. pacificus density remained unchanged for seven and 14 d if there were an average of five and three S. sexmaculatus per trap per week, respectively. Growers who adopt the action and treatment thresholds presented herein have the potential to avoid unnecessary miticide use, maximize reliance on biological control, and promote the long-term sustainability of California's almond industry.

Each year, consultants and field scouts working in commercial agriculture undertake a massive, decentralized data collection effort as they monitor insect populations to make real-time pest management decisions. These data, if integrated into a database, offer rich opportunities for applying big data or ecoinformatics methods in agricultural entomology research. However, questions have been raised about whether or not the underlying quality of these data is sufficiently high to be a foundation for robust research. Here I suggest that repeatability analysis can be used to quantify the quality of data collected from commercial field scouting, without requiring any additional data gathering by researchers. In this context, repeatability quantifies the proportion of total variance across all insect density estimates that is explained by differences across populations and is thus a measure of the underlying reliability of observations. Repeatability was moderately high for cotton fields scouted commercially for total Lygus hesperus Knight densities (R = 0.631) and further improved by accounting for observer effects (R = 0.697). Repeatabilities appeared to be somewhat lower than those computed for a comparable, but much smaller, researcher-generated data set. In general, the much larger sizes of ecoinformatics data sets are likely to more than compensate for modest reductions in measurement precision. Tools for evaluating data quality are important for building confidence in the growing applications of ecoinformatics methods.

Aphidius colemaniViereck is an important parasitoid of green peach aphid [Myzus persicae (Sulzer)], a serious pest of greenhouse crops. Augmentation of natural enemies is the most used approach to biological control of greenhouse pests. Yet, the optimal release time, rate, and age of natural enemies are often unclear. Here we tested the influence of population density of both A. colemani and M. persicae, as well as parasitoid age, on parasitism and sex allocation. We aim is to provide information for cost-effective aphid biological control programs. We show that 1) parasitoid females increased parasitism and produced more female-biased offspring with an increase of aphid density, 2) a moderate increase of parasitoid release rate elevated parasitism and daughter production when aphid density was high, 3) parasitism rate declined with an increase of aphid density but the moderate increase of parasitoid release rate eased the decline rate, and 4) 3-d-old parasitoids parasitized more aphids than younger ones but parasitoid age had no effect on daughter production. These findings suggest that A. colemani females can adjust their ability to regulate the aphid population in response to aphid population dynamics. In augmentative programs, a moderate increase of parasitoid release when aphid density is high could achieve effective control and a release of 3-d-old parasitoids could lead to a better control outcome.