To examine the effect of chemical additives on Bacillus thuringiensis (Berliner) against Plutella xylostella (L.), inorganic salts, nitrogenous compounds, protein solubilizing agents, and organic acids were selected and tested. The chosen materials are low in cost and environmentally safe. Results show that many inorganic salts can increase the activity of B. thuringiensis in a range of 1.31-to 3.08-fold. These include calcium acetate, calcium chloride, calcium hydroxide, calcium sulfate, calcium carbonate, sodium carbonate, sodium acetate, potassium hydroxide, potassium carbonate, potassium acetate, magnesium chloride, magnesium sulfate, and zinc sulfate. Nitrogenous compounds, including peptone, sodium nitrate, and ammonium nitrate, can enhance the activity of B. thuringiensis 1.62-, 1.32-, and 1.37-fold, respectively. Among the protein solubilizing agents, EDTA, urea, mercaptoethanol and dipotassium hydrogen phosphate increased the activity of B. thuringiensis 1.62- to 2.34-fold. Among the organic acids, maleic and citric acids boosted the activity 1.45- and 1.55-fold, respectively. Meanwhile, sodium benzoate and resorcinol led to 1.74- and 1.44-fold activity gains, respectively. Use of appropriate additives could provide great benefit not only in reducing the costs for field applications of biological insecticides but also by boosting the efficacy of B. thuringiensis.

The alfalfa leafcutting bee Megachile rotundata (F.) is the primary pollinator for alfalfa seed production. Under standard management conditions, the alfalfa leafcutting bee develops to the diapausing prepupal stage under field conditions, after which they are cold-stored at a static temperature until the following spring, when temperatures are raised and development resumes. We have assessed the effects of a fluctuating thermal regime (FTR) during overwintering cold storage, where bees were exposed to a daily 1 h pulse of 20°C, and compared viability and insect quality to bees stored under a static thermal regime. Our results demonstrate that implementing an FTR protocol dramatically increases the survival of cold-stored alfalfa leafcutting bees, effectively extending their shelf-life into the subsequent growing season. These findings could substantially ameliorate significant obstacles that restrict the more widespread use of this important pollinator, such as the biological constraints that restrict its use in early blooming crops, and yearly fluctuations in bee prices that add significant financial uncertainty to end users. This study also strengthens a growing body of evidence that indicates FTR protocols are superior to static thermal regime protocols for insect cold storage.

The alfalfa leafcutting bee, Megachile rotundata (F.), is a solitary, cavity-nesting bee and is the primary pollinator for alfalfa seed production. Bee management practices include cold storage during the prepupal stage. Fluctuating thermal regimes during cold storage increases survival of cold storage and allows a doubling of the cold storage period with no decrease in survival. However, survival, characterized as successful adult emergence, is not qualitative. In this study, we determined whether extended storage affects adult bee respiration or flight physiology. We overwintered bees for a single winter (current management protocol) or for 12 mo longer (extended storage). We used resting and tethered flight metabolic rates and resting critical PO₂ (the oxygen partial pressure below which metabolism can no longer be sustained) as indices of adult bee quality. We found no significant differences in body mass, resting or flight metabolic rates, or critical PO₂ between the two groups. Together these data indicate that extended storage of M. rotundata produces bees of similar respiratory capacity and flight ability. These findings could increase the use of M. rotundata as an alternative pollinator, allowing for extended storage to time adult emergence with early blooming crops.

Bacillus thuringiensis (Bt) (Berliner) strain LLP29 produces a crystal protein Cyt1Aa6 toxic to mosquito vectors of human diseases. However, the susceptibility of Culex quinquefasciatus (Say) in the current study was 8.25 times higher than that of Aedes albopictus (Skuse) with this single protein Cyt1Aa6 purified from LLP29. To understand the mechanism of the novel mosquitocidal protein, the binding characteristic of brush border membrane vesicles from the two tested mosquitoes was investigated. Enzyme-linked immunosorbent assay showed that Cyt1Aa6 bound to the two mosquitoes’ brush border membrane vesicles. However, the titer of Ae. albopictus was a little higher than that of Cx. quinquefasciatus, with 3.21 and 2.91, respectively. Ligand Western blot analysis showed Cyt1Aa6 toxin specifically bound to the same three proteins (i.e., 68, 54, and 26 kDa) in the two mosquitoes, but one another protein, approximately to 37 kDa, could just be detected in Cx. quinquefasciatus. However, little difference was found in the test of immunohistochemistry. Cyt1Aa6 was detected in the midguts of both mosquitoes with histopathological changes. It would of great importance to the knowledge of the novel toxin against to Cx. quinquefasciatus and Ae. albopictus.

The tools of insect pest management include host plant resistance, biological control, and insecticides and how they are integrated will influence the durability of each. We created a detailed model of the population dynamics and population genetics of the diamondback moth, Plutella xylostella L., and its parasitoid, Diadegma insulare (Cresson), to study long-term pest management in broccoli Brassica oleracea L. Given this pest's history of evolving resistance to various toxins, we also evaluated the evolution of resistance to transgenic insecticidal Bt broccoli (expressing Cry1Ac) and two types of insecticides. Simulations demonstrated that parasitism provided the most reliable, long-term control of P. xylostella populations. Use of Bt broccoli with a 10% insecticide-free refuge did not reduce the long-term contribution of parasitism to pest control. Small refuges within Bt broccoli fields can delay evolution of resistance >30 generations if resistance alleles are rare in the pest population. However, the effectiveness of these refuges can be compromised by insecticide use. Rainfall mortality during the pest's egg and neonate stages significantly influences pest control but especially resistance management. Our model results support the idea that Bt crops and biological control can be integrated in integrated pest management and actually synergistically support each other. However, the planting and maintenance of toxin-free refuges are critical to this integration.

The efficacy of entomopathogenic nematodes (EPNs) against the white grub Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae) in the peanut (Arachis hypogaea L.) fields was evaluated. In the first experiment with a high initial white grub population (24.65 ± 2.44 larvae per m²) in the field, Steinernema longicaudum X-7 and Heterorhabditis bacteriophora H06 at 10,000 and 5,000 infective juveniles (IJs) per plant contributed to significantly higher percentage reduction of the white grub larvae, lower percentage of the injured legume, and higher peanut yield compared with chlorpyrifos and other treatments. The peanut yields harvested from the plots treated with EPNs at 5,000 IJs per plant were at least 70% higher than that from the untreated control (water) and at least 30% higher than that from chlorpyrifos-treated plots. In the second experiment with a low initial white grub population (8.07±1.29 larvae per m²) in the field, EPN treatment did not increase peanut yield compared with the other treatments. But both S. longicaudum X-7 and H. bacteriophora H06 gained higher percentage reduction of the white grub larvae and lower percentage of the injured legume than Steinernema carpocapsae (Weiser) All and the control. The cost-benefit of using EPNs for white grub control was estimated to be comparable with that of using chemicals. S. longicaudum X-7 and H. bacteriophora H06 showed promise for white grub control in peanut fields.

The susceptibility of preimaginal and adult olive fruit fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae), to a strain of the mitosporic ascomycete Metarhizium brunneum (Petch) (Hypocreales: Clavicipitaceae) and the insecticidal activity of its crude extract to olive fruit fly adults were investigated. Strain EAMb 09/01-Su caused 60% mortality to B. oleae adults, with average survival time (AST) of 8.8 d. In soil treatments against pupariating third-instar larvae, preimaginal B. oleae mortality reached 82.3%, whereas preimaginal mortality targeting puparia was 33.3%. The crude extract of EAMb 09/01-Su strain caused 80.0% adult mortality when administered per os, with AST of 27.7 h. The crude extract was demonstrated to be quite thermostable and photoresistant. These results indicate that M. brunneum EAMb 09/01-Su strain and its crude extract show potential to be used in an integrated pest management olive fruit fly management strategy targeting both adults and preimaginals.

This study compared lethal and sublethal effects of five insecticides, chlorantraniliprole, cyantraniliprole, spinetoram, novaluron, and lambda-cyhalothrin, on adult and second instars of two green lacewing species, Chrysoperla carnea (Stephens) and Chrysoperla johnsoni Henry, Wells and Pupedis (Neuroptera: Chrysopidae) in the laboratory. Formulated pesticides were tested using concentrations equivalent to the high label rate dissolved in 378.5 liters of water. Novaluron and lambda-cyhalothrin were toxic to larvae and no treated larvae survived to the adult stage. Larva to adult survival was reduced in chlorantraniliprole, cyantraniliprole, and spinetoram treatments. Larva to adult developmental time and sex ratio were not different among the treatments within a species. Chlorantraniliprole, cyantraniliprole, spinetoram, and lambda-cyhalothrin treatments were highly toxic to adults of both species. C. johnsoni females had lower fecundity than C. carnea females in the control. Fecundity of females was similar in the control and novaluron treatment within each species. However, fertility and egg viability were negatively impacted for both species when females were treated with novaluron. C. carnea females had higher fertility and egg viability than C. johnsoni females in the control. Adults of both species had similar longevity in the control and novaluron treatment and adult longevity was not gender specific. All insecticides tested were toxic to C. johnsoni and C. carnea either at the immature or adult stage or both. Results of this study demonstrate a similarity between C. johnsoni and C. carnea for pesticide toxicity irrespective of their varied geographical distributions.

The aim of the study was to investigate the attractiveness to herbivores and parasitoids of two cultivars of Brassica oleracea L., namely, B. oleracea variety acephala (kale) and B. oleracea variety capitata (cabbage), that exhibit differences of morphological and biochemical traits. To this end, field samplings were replicated at seven localities in Galicia (northwestern Spain). Three specialist and three generalist lepidopteran species were sampled. In total, 7,050 parasitoids were obtained, belonging to 18 genera and 22 species. The results showed that 1) parasitism rate and parasitoid species richness changed with locality and was higher in cabbage, although this crop had lower herbivore abundance; 2) the proportion of specialist herbivores was higher in cabbage crops, whereas generalists dominated in kale crops; 3) the abundance of the parasitoids Telenomus sp. (Hymenoptera, Scelionidae), Cotesia glomerata L. (Hymenoptera: Braconidae), and Diadegma fenestrale (Holmgren) (Hymenoptera: Ichneumonidae) was higher in kale crops; and 4) parasitism rate of Pieris rapae larvae and pupae and Mamestra brassicae eggs were higher in kale crops. In contrast with the notion that plant structural complexity provides physical refuge to the hosts and can interfere with parasitoid foraging, parasitism rate was higher on cabbage plants, which form heads of overlapped leaves. Possibly, different chemical profiles of cultivars also influenced the host-parasitoid relationship. These results suggest that top-down and bottom-up forces may enhance cabbage crops to better control herbivore pressure during the studied season. In Spain, information on natural occurring parasitoid guilds of Brassica crops is still scarce. The data provided here also represent a critical first step for conservation biological control plans of these cultivations.

Tetrastichus planipennisi Yang is a gregarious larval endoparasitoid native to China and has been introduced to the United States since 2007 for classical biological control of the invasive emerald ash borer, Agrilus planipennis Fairmaire, an exotic beetle responsible for widespread ash mortality. Between 2007–2010, T. planipennisi adults (3,311–4,597 females and ≈1,500 males per site) were released into each of six forest sites in three counties (Ingham, Gratiot, and Shiawassee) of southern Michigan. By the fall of 2012, the proportion of sampled trees with one or more broods of T. planipennisi increased to 92 and 83% in the parasitoid-release and control plots, respectively, from 33 and 4% in the first year after parasitoid releases (2009 fall for Ingham county sites and 2010 for other sites). Similarly, the mean number of T. planipennisi broods observed from sampled trees increased from less than one brood per tree in the first year after parasitoid releases to 2.46 (at control plots) to 3.08 (at release plots) broods by the fall of 2012. The rates of emerald ash borer larval parasitism by T. planipennisi also increased from 1.2% in the first year after parasitoid releases to 21.2% in the parasitoid-release plots, and from 0.2 to 12.8% for the control plots by the fall of 2012. These results demonstrate that T. planipennisi is established in southern Michigan and that its populations are increasing and expanding. This suggests that T. planipennisi will likely play a critical role in suppressing emerald ash borer populations in Michigan.

Methyl bromide (MB) chamber fumigations were evaluated for postharvest control of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in fresh fruit destined for export from California. To simulate external feeding, larvae were contained in gas-permeable cages and distributed throughout loads of peaches, plums, nectarines (all Prunus spp.), apples (Malus spp.), raspberries (Rubus spp.), or grapes (Vitis spp.). Varying the applied MB dose and the differential sorption of MB by the loads resulted in a range of exposures, expressed as concentration x; time cross products (CTs) that were verified by gas-chromatographic quantification of MB in chamber headspace over the course of each fumigation. CTs ≥60 and ≥72 mg liter^-1 h at 10.0 ± 0.5 and 15.6 ± 0.5°C ( ± s, average ±SD), respectively, yielded complete mortality of ≈ 6,200 larvae at each temperature. These confirmatory fumigations corroborate E. postvittana mortality data for the first time in relation to measured MB exposures and collectively comprise the largest number of larval specimens tested to date. In addition, a kinetic model of MB sorption was developed for the quarantine fumigation of fresh fruit based on the measurement of exposures and how they varied across the fumigation trials. The model describes how to manipulate the applied MB dose, the load factor, and the load geometry for different types of packaged fresh fruit so that the resultant exposure is adequate for insect control.

Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae) puparia are of regulatory concern in exported hay, and drying after harvest was evaluated as a cultural control technique for bales shipped from the western states. In total 16,836; 31,122; and 48,051 puparia were tested under drying conditions in environmental chambers, open air on location, and hay windrows, respectively. Regression lines for percentage of total adults emerging from puparia exposed to simulated drying conditions for 1–7 d in environmental chambers was significant for 1 September, Kittitas Valley, WA; 3 June, East Columbia Basin, WA; 15 May and 15 July, San Joaquin Valley, CA; and 15 May, 20 July, and 15 September, Imperial Valley, CA. In open air drying on location for 1–7 d, total percentage of puparia surviving to adults for all exposure days was 0.4% for 18 June, Kittitas Valley; 1.2% for 15 May, San Joaquin Valley; and 0% for 16 July, Imperial Valley; and significantly different between controls and exposure durations. In hay windrow drying for 1–6 d, total percentage of puparia surviving to adults for all exposure days was 5.4% on 28 June and 24.2% on 7 September in timothy, Phleum pretense, in the Kittitas Valley; 3.8% on 28 June in timothy in the East Columbia Basin; 2.2% on 20 July in alfalfa, Medicago sativa, in the San Joaquin Valley; and 6.3% on 21 July in Sudan grass, Sorghum bicolor sudanensis, in the Imperial Valley. The number of puparia surviving to adults in open air drying and in windrows was significantly different between controls and exposure durations for all test dates and locations. Puparial survival in field tests was related to mild temperatures and high humidities. Hay drying with subsequent field baling, storage, and export bale compression is discussed in relation to a systems approach for quarantine control of Hessian fly in exported hay.

The efficacy of low-oxygen atmospheres using low pressure, referred to as hypobaric conditions, to kill egg and third-instar Rhagoletis pomonella (Walsh) in apples was investigated. Infested apples were exposed to 3.33 and 6.67 kPa in glass jars at 25 and 30°C for times ranging from 3 to 120 h. Probit analyses and lethal dose ratio tests were performed to determine differences in lethal time values. Eggs were more tolerant of low pressure compared with third-instar R. pomonella. Mortality of eggs and larvae increased with increase in time of exposure to low pressure and temperature. Lower pressures increased percent mortality of eggs, but these values were not significantly different at the pressures tested in this investigation. The LT₉₉ for R. pomonella eggs at 3.33 kPa was 105.98 and 51.46 h, respectively, at 25 and 30°C, which was a significant effect of the higher temperature on egg mortality. Investigation into consumer acceptance of low-pressure-treated apples was done with ‘Red Delicious’ and ‘Golden Delicious’. Apples exposed to 3.33 kPa at 25 and 30°C for 3 and 5 d were stored at 1°C for 2 wk and presented to a sensory panel for evaluation. The panelists rated treated apples with untreated controls for external and internal appearance and taste. Golden Delicious apples were unaffected for all three sensory factors across both temperatures and exposure times. Although taste was unaffected for Red Delicious, the internal and external appearances deteriorated. Use of low pressure for disinfestation and preservation of apples is a potential nonchemical alternative to chemical fumigants such as methyl bromide and phosphine.

South Africa imports plant budwood (dormant cuttings for propagation) from various countries. Phytosanitary measures, including inspections at points of entry, are implemented to minimize the chance of a pest being introduced on the budwood. This study presents the inspections and interceptions of mites and insects on budwood imported to South Africa from 2004 to 2011. The study presents crops and countries from which South Africa imports budwood, and gives data on the type of imports more often infested with arthropods. Interceptions of insects and mites are reported, including interceptions of phytosanitary, economically important and nonphytophagous mites. The arthropod taxa intercepted are listed, and it is noted that the majority of interceptions are of mites, particularly of Eriophyoidea. These data are discussed in the context of quarantine and research.

Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is an important quarantine pest of nurseries. Nursery plant movement from P. japonica-infested regions is regulated by the U.S. Domestic Japanese Beetle Harmonization Plan (DJHP), which classifies states by risk categories. Treatments for category 2 states include preharvest soil surface treatment of nursery plants grown in field soil using Discus SC, Marathon (1G or 60 WP), or Flagship (0.22G or 25 WG). In this study, Discus, Marathon 60 WP, or Flagship 0.22G DJHP standards were compared with labeled rates of non-DJHP-approved insecticides, including neonicotinoids clothianidin (Arena 50WDG), generic imidacloprid (Quali-Pro Imidacloprid 2 F T&O Insecticide, Mallet 2 F T&O Insecticide, and Lada 2 F Insecticide), and imidacloprid bifenthrin (Allectus SC), as well as the anthranilic diamide, chlorantraniliprole (Acelepryn Insecticide). Arena provided 100% P. japonica control in May, June, and July over four test years, but had one larva recovered during August in two of those 4 yr. Acelepryn did not provide DJHP-acceptable P. japonica control. During July, Allectus provided 100% P. japonica control in three of four test years, but had four larvae in one test year. Other treatments tested only during July, which provided 100% P. japonica control, included Discus (five tests); Marathon, QualiPro, and Mallet (two tests); and Lada and Flagship (one test). Generic imidacloprid 2 F formulations were equivalent in P. japonica control to DJHP-approved insecticides. Insecticides generally performed poorly on other scarabs or curculionid larvae. The study supports Arena, Allectus, and generic imidacloprid 2 F products as suitable candidates for the DJHP.

Diet nutrient is considered as an important regulatory factor for reproduction of insects. To understand the effect of different food sources on the reproductive physiology ofApolygus lucorum (Meyer-Diir), the ovarian development in adult females was investigated when they were fed on green beans (Gb), combination of green beans Phaseolus vulgaris L and Helicoverpa armigera eggs (GbHe), or H. armigera eggs (He). A female of A. lucorum has two ovaries, and each ovary contained seven yellowish ovarioles. Females fed on Gb or GbHe had larger ovaries and the ovarioles contained larger numbers of oocytes compared with those fed on He. Females in GeHe treatment has significantly higher number of follicles per ovary throughout the whole adult period compared with those in Gb or He treatment. Furthermore, the length of the best developed ovariole was affected by the diet type. The females fed on GbHe had the most developed ovarioles, with significantly longer ovarioles than those fed on Gb or He. A method was described to quantitatively score the degree of ovarian development in the current study. Similarly, the ovarian development scores were significantly higher for females in GbHe treatment than those in other two diet treatments. The ovarian development significantly delayed for females fed on He. Our results demonstrate that A. lucorum, as an omnivorous insect species, can acquire nutrients from both plant and animal origin food sources, and the combination of plants and animal food sources can significantly facilitate the ovary development of its females.

A 3-yr field study quantified the compensatory ability of cotton (Gossypium hirsutum L.) to preflower fruit damage by Lygus hesperus Knight in the Texas High Plains under limited irrigation. Experiments were designed to achieve varying levels of preflower fruit loss by augmenting Lygus bug populations using nymphal bugs reared in a laboratory colony. Treatments included 1) three bugs per plant (3PP), 2) one bug per plant (1PP), 3) naturally occurring background bug density or untreated control (NC), and 4) 0 bugs achieved through insecticide spray applications (SC). Lygus release treatments (3PP and 1PP) were initiated at early fruiting (squaring) and repeated weekly for a total of three consecutive weeks. Two levels of Lygus bug infestations, one insect per plant (1PP) and three insects per plant (3PP), inflicted fruit loss percentages of 24–38 during the maximum fruit set period. Observations on the number of fruit lost at the crop preharvest stage indicate that plants receiving the 3PP and 1PP treatments exhibited higher ability to restrain physiological fruit loss when compared with the two control treatments (NC and SC). Cotton plants could not fully compensate the yield loss because of fruit damage caused by Lygus bugs at the observed level of damage. The total lint yields in the 1PP and 3PP treatments were 114 and 118 kg/ha lower, respectively, compared with that in treatment SC. The reduction in yield was primarily because of the loss of first fruiting position bolls. However, lint yields from bolls other than first position of the cotton plant were similar across treatments. Fiber quality data indicated an increase in fiber length from insect release treatment plants compared with the two control treatments.

The asparagus miner is an obligatory feeder on asparagus and a putative vector for pathogenic fungi implicated in the early decline of asparagus fields. To date, the distribution of the asparagus miner over space and time is poorly understood. Our study evaluated the spatial and temporal pattern of adult asparagus miners in commercial asparagus fields in Michigan in 2011 and 2012. We sampled adults and damage weekly during the growing season using yellow sticky traps outside, at the edge, and inside commercial fields. Yellow sticky traps at each trapping location were placed at the canopy and ground level to determine vertical distribution of adults. During the first generation, adults were more evenly distributed throughout the field. In the second generation, adults were more commonly found on the edge of the field. Overall, there was a greater percent of mining damage near the edge of the field. Additionally, three times as many asparagus miners were found in the canopy compared with ground-level traps. There were 12 times as many asparagus miner adults on edges bordered by another asparagus field than on ones bordered by forest. Taken together, our results indicate that while asparagus miner management in the beginning of the growing season should focus on the entire field, in the latter half of the season, growers could save money and resources by targeting miner adults at the edges of fields. Finally, conserving the remaining naturally forested landscape and planting borders of trees may help ameliorate pest pressure in asparagus fields.

Vienna-8 sterile males are currently released in Spain to reduce wild populations of the medfly. Because pesticides are required to maintain populations of some citrus key pests below economic thresholds, there is a need to evaluate the effects of pesticides commonly used in citrus on Vienna-8 males. Males were exposed to differently aged residues of eight pesticides. Abamectin, etofenprox, etoxazole, petroleum spray oil, pymetrozine, and pyriproxyfen resulted harmless to Vienna-8 males. However, fresh residues of chlorpyrifos and spinosad caused high mortalities and had residual effects until 21 and 28 d after treatment, respectively. Following the same method, the lethal effects of chlorpyrifos and spinosad on Ceratitis capitata (Wiedemann) wild-type (wt) males were determined. Surprisingly, these pesticides resulted more toxic for wt than for Vienna-8 males. To determine whether these results could be attributed to intrinsic characteristics of the pesticides or to behavioral differences among Vienna-8 and wt males, a topical application trial was conducted. Vienna-8 males were twice as susceptible to chlorpyrifos as wt males, whereas their susceptibility to spinosad was slightly lower. These results in intrinsic toxicity did not directly explain the differences observed in the extended-laboratory tests with these pesticides. We hypothesize that the lower flight activity of Vienna-8 males relative to wt conspecifics can explain the lower risk observed for Vienna-8 males in the residual tests. Our results should be taken into account when planning area-wide Sterile Insect Technique programs against C. capitata especially in those areas where treatments with chlorpyrifos are approved.

In the Mediterranean area, the main corn borer species are Sesamia nonagrioides Lefebvre (Mediterranean corn borer) and Ostrinia nubilalis Hübner (European corn borer). In the overall context of integrated pest control, it is possible to reduce the effect of a pest without having a negative effect on the environment by varying the sowing date. Benefits are possible if the most susceptible stages of the crop no longer coincide with the peak of the pest. We used different cycles of selection (0, 6, 8, 10, and 12) of two populations (Purdue A and Purdue B) of maize selected for early flowering to get a more precise estimation of the relationship between maturity of plant tissues and corn borer damage. We found a relationship between the damage produced by corn borers and the number of days from flowering to infestation. We conclude that, after flowering, a later stage of plant development at the moment of the infestation by corn borers reduces the damage caused by the larvae. Based on our results, we recommend to plant as early as possible so the tissues would be as mature as possible at the moment of insect attack.

Many studies have reported the effect of nitrogen (N) fertilization on plant constitutive defense responses; however, little is known about their effects on plant induced defense patterns and its consequence for insect herbivores. In our experiments, the effects of N availability on growth, nutritional quality (N content, protein/carbohydrate [P:C] ratio, modified gross energy [MGE]), and constitutive phenolics of corn, Zea mays L. were quantified. Moreover, the indirect effects of N fertilization on the beet armyworm, Spodoptera exigua Hübner through larval performance and feeding preference were examined. N fertilization increased plant growth, and depressed defense traits by increasing N content and the P:C ratio, as well as decreasing the constitutive concentration of phenolics. Subsequently, beet armyworm showed higher performance and preferentially fed on high-N corn because of its low defense traits. After beet armyworm feeding, high-N corn significantly deterred larval feeding, and had negative effects on the performance of beet armyworm through decreasing P:C ratio and increasing induced phenolics. On the contrary, there were no significant changes in P:C ratio and phenolics in low-N corn after feeding damage. Larval performance and preference were also not affected by induced compounds in low-N corn, which suggested that the expression of induced defense was dependent on N availability. The result indicates that N availability can exert a variety of bottom-up effect on plant defense patterns to influence insect population dynamics, and thereby may represent a source of variation in plant-insect interactions.

Corn earworm, Helicoverpa zea (Boddie), is apolyphagous noctuid pest of agricultural crops across the United States that is gaining attention as a pest of field corn. Before the introduction of transgenic insect-resistant hybrids, this pest was largely ignored in field corn, but now many Bacillus thuringiensis (Bt) corn hybrids have activity against corn earworm. However, the value of control in the northeastern United States is unclear because the risk posed by corn earworm to field corn has not been well characterized. To understand the threat from corn earworm and the value of Bt hybrids in field corn, we assessed corn earworm injury in Bt and non-Bt hybrids at 16 sites across four maturity zones throughout Pennsylvania in 2010, and 10 sites in 2011. We also used corn earworm captures from the PestWatch pheromone trapping network to relate moth activity to larval damage in field corn. Corn earworm damage was less than one kernel per ear at 21 of 26 sites over both years, and the percentage of ears damaged was generally <15%, much lower than in the southern United States where damage can be up to 30 kernels per ear. At sites with the highest damage levels, Bt hybrids suppressed corn earworm damage relative to non-Bt hybrids, but we found no differences among Bt traits. Cumulative moth captures through July effectively predicted damage at the end of the season. Currently, the additional benefit of corn earworm control provided by Bt hybrids is typically less than US$4.00/ha in northeastern field corn.

The abundance and distribution of insect herbivores is determined by, among other things, plant quality and natural enemies. These two factors vary temporally and spatially, subsequently affecting seasonal population dynamics. The relative influence of plant quality and natural enemies on the seasonal dynamics of Bemisia tabaci (Gennadius) was investigated in a 3-yr field study in cotton. Plant quality was manipulated through varying irrigation regimes: irrigations done at 20, 40, and 60% soil water depletions; and natural enemy densities were manipulated using broad spectrum insecticide applications that reduced their densities compared with unsprayed controls. In each year, densities of B. tabaci eggs, large nymphs and adults were consistently higher when natural enemy densities were reduced compared with when they were left unaltered, regardless of irrigation regime. In contrast, effects of plant quality on densities of all whitefly stages were weak and inconsistent. In addition, natural enemy densities and predator:prey ratios also were not generally affected by plant quality. Interactions between natural enemies and plant quality on whitefly dynamics were rare. In general, whitefly densities were elevated two-thirds of the time and increased two- to sixfold when natural enemy densities were reduced compared with plant quality effects which influenced whitefly densities about one-third of the time and were expressed inconsistently over the years. This indicates that natural enemies exert a comparatively greater influence on seasonal dynamics of B. tabaci in cotton than plant quality, as manipulated by differential irrigation.

Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.). Historically, the western bean cutworm was distributed in the western United States, but since 1999 eastward expansion has been observed. In corn, economic impact is caused by larval ear feeding. Information on western bean cutworm biology, ecology, and economic impact is relatively limited, and the development of economic injury levels (EILs) and economic thresholds (ETs) is required for more effective management. Studies during 2008–2011, across three ecoregions of Nebraska, sought to characterize western bean cutworm survival and development of EILs and ETs. Calculations of EILs and ETs incorporated the dynamics of corn price, management cost, and pest survival. The results from the current study demonstrated low larval survival of this species (1.51–12.82%). The mean yield loss from one western bean cutworm larva per plant was 945.52 kg/ha (15.08 bu/acre), based on 74,100 plants per ha. Economic thresholds are expressed as a percentage of plants with at least one egg mass. This study is the first study that explicitly incorporates variable management costs and crop values into western bean cutworm EIL calculations, and larval survival into ET calculations.

Because the farmer is typically excluded from the experimental research setting, experimental research may face challenges in evaluating pest management tactics whose costs and benefits hinge on farmer decision-making. In these cases an ecoinformatics approach, in which observational data collected from the commercial farming setting are “mined” to quantify both biological variables and farmer behavior, can complement experimentation as a useful research tool. Here I analyze such an observational data set to characterize associations between early- (June) and mid-season (July) Lygus hesperus Knight populations and farmer decisions to apply plant growth regulators and defoliants. Previous experimental work suggested the hypothesis that Lygus herbivory, by inducing abscission of young flower buds, might generate increased use of plant growth regulators and defoliants. Cotton's ability to compensate for loss of flower buds may, however, increase as plants grow. On upland cotton, June Lygus populations were associated with increased use of plant growth regulators, as expected, but this relationship was not observed for July Lygus populations. June Lygus populations were not associated with the use of defoliants, whereas, surprisingly, July Lygus populations were associated with decreases in defoliant use. In contrast to these positive and negative associations observed on upland cotton, on Pima cotton Lygus populations exhibited no associations with use of either plant growth regulators or defoliants. These results suggest that cotton responses to Lygus herbivory, as demonstrated in previously published experimental studies, can translate into economically meaningful changes in farmer decisions to apply agricultural chemicals.

Cultural control measures should play an important role in cereal aphid management on wheat and barley. Planting barley in fields adjacent to those of wheat and intercropping wheat with barley are cultural practices that might suppress the cosmopolitan cereal pest Sitobion avenae (F.). To evaluate the potential effects of these cultural measures on aphid outbreak risks, clones of S. avenae were collected from wheat and barley. Host-switch experiments for the collected clones were conducted in the laboratory to compare their life table parameters and other life history traits. Our results demonstrated that wheat clones of S. avenae had lower developmental times, higher fecundities, and higher growth rates compared with barley clones when tested on the plant of origin. When transferred to barley, the performance of wheat clones was decreased in terms of developmental times of nymphs and age at first reproduction of adults. Barley clones' performance was decreased in terms of reproductive time or lifespan of adult on wheat compared with that on barley. The age-specific survival rates of barley clones tended to be lower than wheat clones in the earlier part of their lives on wheat. The age-specific fecundity of barley clones on barley remained low and fluctuated significantly during their lifetime. Although quite a few significant correlations between developmental and reproductive traits were identified on both plants, no significantly negative correlations (i.e., trade-offs) for the traits were found between plants. The results suggested that barley clones could be generalized but wheat clones were more specialized to their host plant. The potential benefits of the abovementioned cultural measures were discussed.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) is a significant soybean pest in the north central United States. Insecticidal seed treatments and host plant resistance are two commercially available management tools. Here we investigate the efficacy of both management tools throughout the season. Soybean lines containing the soybean aphid resistance genes Rag1, Rag2, or both Rag1 Rag2 were compared with a near-isogenic aphid-susceptible line. Each line was grown in field plots both with and without thiamethoxam applied to the seed. Individual plants from each plot were caged and infested with soybean aphids to measure the efficacy and potential interaction of aphid resistance and thiamethoxam. Aphid population growth rate was measured for each caged plant for 9–12 d after infestation. New cages were established each week from 34 d after planting (dap) to 92 dap to track seasonal variations in efficacy. Thiamethoxam reduced population growth only at the 42 dap time point and only for the susceptible, Rag1, and Rag2 lines. The lack of an effect of thiamethoxam on the Rag1 Rag2 line was likely because of already high mortality from two resistance genes. Aphid resistance alone reduced population growth compared with the susceptible line at least till 55 dap for single-gene resistance and 63 dap for the two genes combined. Aphid resistance provided suppression of soybean aphid population growth throughout the season unlike the insecticidal seed treatment.

The ability to monitor verde plant bug, Creontiades signatus Distant (Hemiptera: Miridae), and the progression of cotton, Gossypium hirsutum L., boll responses to feeding and associated cotton boll rot provided opportunity to assess if single in-season measurements had value in evaluating at-harvest damage to bolls and if multiple in-season measurements enhanced their combined use. One in-season verde plant bug density measurement, three in-season plant injury measurements, and two at-harvest damage measurements were taken in 15 cotton fields in South Texas, 2010. Linear regression selected two measurements as potentially useful indicators of at-harvest damage: verde plant bug density (adjusted r² = 0.68; P = 0.0004) and internal boll injury of the carpel wall (adjusted r² = 0.72; P = 0.004). Considering use of multiple measurements, a stepwise multiple regression of the four in-season measurements selected a univariate model (verde plant bug density) using a 0.15 selection criterion (adjusted r² = 0.74; P = 0.0002) and a bivariate model (verde plant bug density-internal boll injury) using a 0.25 selection criterion (adjusted r² = 0.76; P = 0.0007) as indicators of at-harvest damage. In a validation using cultivar and water regime treatments experiencing low verde plant bug pressure in 2011 and 2012, the bivariate model performed better than models using verde plant bug density or internal boll injury separately. Overall, verde plant bug damaging cotton bolls exemplified the benefits of using multiple in-season measurements in pest monitoring programs, under the challenging situation when at-harvest damage results from a sequence of plant responses initiated by in-season insect feeding.

The nonnative brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), has become an abundant pest of mid-Atlantic soybean since its introduction in the mid-1990s. Currently, there is little information indicating how this new pest should be managed in soybean or if economic thresholds developed for native stink bugs should be adjusted. In 2010 and 2011, field cage studies were conducted in Beltsville, MD, and Suffolk, VA, to evaluate H. halys injury to three different soybean reproductive development stages. Cages were infested for 2 wk using densities of zero, one, two, four, or eight stink bugs (fifth instars and adults) per 0.3 row-m. Cage plots were harvested, and subsamples were taken to determine pod losses and seed quality. Feeding injury to soybean caused by H. halys was similar to that of native stink bugs, as evidenced by seed destruction, punctures, and destroyed pods. Densities of four stink bugs per 0.3 row-m resulted in significant seed damage in three of four experiments. The full flowering (R2) soybean development stage was least affected by H. halys feeding. The full pod (R4) and the full seed (R6) stage were similarly sensitive to injury. There was no significant yield loss was associated with stink bug densities at either location, although there were significant differences among stages in two of four experiments. The data do not indicate that threshold densities for H. halys should be different than for the native stink bugs.

Beech scale (Cryptococcus fagisuga Lindinger) (Hemiptera: Eriococcidae) is an invasive forest insect established in the eastern United States and Canada. It predisposes American beech (Fagus grandifolia Ehrhart) trees to infection by Neonectria spp. Fungi causing beech bark disease. White wax secreted by the diminutive scales obscures individual insects, making it difficult to accurately quantify beech scale density. Our goals were to 1) evaluate the relationship between the area of wax and number of beech scales on bark samples, 2) determine whether digital photos of bark could accurately quantify beech scale density, and 3) compare efficiency and utility of a qualitative visual estimate and using the quantitative digital photo technique to assess beech scale populations. We visually estimated beech scale abundance and photographed designated areas on the trunk of 427 trees in 40 sites across Michigan. Photos were analyzed using a binary threshold technique to quantify the area of beech scale wax on each photo. We also photographed and then collected 104 bark samples from 45 additional beech trees in ten sites. We removed the wax, counted individual scales on each sample using a microscope, and assessed the linear relationship between wax area and scale counts. Area of wax explained ≈80% of the variability in scale density. We could typically quantify beech scale density on 15 photographs per hour. Qualitative visual assessments of beech scale in the field corresponded with estimates derived from photos of bark samples for 79% of trees.

The whitespotted sawyer, Monochamus scutellatus scutellatus (Say) (Coleoptera: Cerambycidae), is one of the most damaging wood-boring insects in recently burned boreal forests of North America. In Canada, salvage logging after wildfire contributes to maintaining the timber volume required by the forest industry, but larvae of this insect cause significant damage that reduces the economic value of lumber products. This study aimed to estimate damage progression as a function of temperature in recently burned black spruce (Picea mariana (Miller) Britton, Sterns, and Poggenburg) and jack pine (Pinus banksiana Lambert) trees. Using axial tomographic technology, we modeled subcortical development and gallery depth progression rates as functions of temperature for both tree species. Generally, these rates were slightly faster in black spruce than in jack pine logs. Eggs laid on logs kept at 12°C did not hatch or larvae were unable to establish themselves under the bark because no larval development was observed. At 16°C, larvae stayed under the bark for >200 d before penetrating into the sapwood. At 20°C, half of the larvae entered the sapwood after 30–50 d, but gallery depth progression stopped for ≈70 d, suggesting that larvae went into diapause. The other half of the larvae entered the sapwood only after 100–200 d. At 24 and 28°C, larvae entered the sapwood after 26–27 and 21 d, respectively. At 28°C, gallery depth progressed at a rate of 1.44 mm/d. Temperature threshold for subcortical development was slightly lower in black spruce (12.9°C) than in jack pine (14.6°C) and it was 1°C warmer for gallery depth progression for both tree species. These results indicate that significant damage may occur within a few months after fire during warm summers, particularly in black spruce, which highlights the importance of beginning postfire salvage logging as soon as possible to reduce economic losses.

Larvae of cranberry tipworm, Dasineura oxycoccana Johnson, disrupt early season growth of cranberry (Vaccinium macrocarpon Aiton) uprights or shoots by feeding on apical meristem tissue. A 2-yr field study was carried out at three different locations to determine the impact of tipworm feeding injury on the reproductive and vegetative growth of two cranberry cultivars (‘Howes’ and ‘Stevens’) in Massachusetts. In addition to tipworm-injured and intact control uprights, an artificial injury treatment simulating tipworm feeding was also included. Individual uprights of cranberry exhibited tolerance to natural (tipworm) and simulated apical meristem injury in the current growing season (fruit production) and results were corroborated by a greenhouse study. In the field study, weight of fruit was higher in tipworm-injured uprights as compared with intact control uprights at the sites with Howes. However, majority of injured uprights (tipworm and simulated) did not produce new growth from lateral buds (side-shoots) before the onset of dormancy. In the next growing season, fewer injured uprights resumed growth and produced flowers as compared with intact uprights at two of the three sites. We suggest that multiple-year studies focusing on whole plant response to tipworm herbivory will be required to determine the costs of chronic feeding injury over time.

In our screening program for insecticidal activity of the essential oils/extracts derived from some Chinese medicinal herbs and spices, garlic (Allium sativum L.) essential oil was found to possess strong insecticidal activity against overwintering adults of Cacopsylla chinensis Yang et Li (Hemiptera: Psyllidae). The commercial essential oil of A. sativum was analyzed by gas chromatography-mass spectrometry. Sixteen compounds, accounting for 97.44% of the total oil, were identified, and the main components of the essential oil of A. sativum were diallyl trisulfide (50.43%), diallyl disulfide (25.30%), diallyl sulfide (6.25%), diallyl tetrasulfide (4.03%), 1,2-dithiolane (3.12%), allyl methyl disulfide (3.07%), 1,3-dithiane (2.12%), and allyl methyl trisulfide (2.08%). The essential oil of A. sativum possessed contact toxicity against overwintering C. chinensis, with an LC₅₀ value of 1.42 µg per adult. The two main constituent compounds, diallyl trisulfide and diallyl disulfide, exhibited strong acute toxicity against the overwintering C. chinensis, with LC₅₀ values of 0.64 and 11.04 µg per adult, respectively.

The Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) cryptic species complex of whitefiies contains two species, MEAM1 and MED, that are highly invasive in supportive climates the world over. In the United States, MEAM1 occurs both in the field and in the greenhouse, but MED is only found in the greenhouse. To make inferences about the population structure of both species, and the origin and recent spread of MED within the United States, 987 MEAM1 whitefiies and 340 MED whitefiies were genotyped at six and seven microsatellite loci, respectively, for population genetic analyses. Major results of the study are 1) MED exhibits more population structure and genetic differentiation than MEAM1, 2) nuclear microsatellite markers exhibit a high degree of concordance with mitochondrial markers recovering a major east-west phylogeographic break within MED, 3) both eastern and western MED are found throughout the continental United States and eastern MED is present in Hawaii, and 4) MEAM1 contains two greenhouse U.S. populations significantly differentiated from other U.S. MEAM1. The results suggest that MED was introduced into the United States on at least three occasions and rapidly spread throughout the United States, showing no discernible differentiation across 7,000 km. The results further suggest that there is an enhanced role of the protected agricultural environment in promoting genetic differentiation in both invasive B. tabaci cryptic species.

Laboratory and field studies are reported that assess navel orangeworm (Amyelois transitella (Walker)) development and damage on 11 almond varieties that represent both expected and outlying hull split and shell seal A. transitella damage. Twenty neonate larvae were introduced to almonds of three treatments for each variety: scratched (1 mm scratch through the pellicle), shelled (shell removed but pellicle intact), and unshelled (shell intact and exhibiting the tightest shell seal for the variety). Success was evaluated as moth emergence and degree-days (DD) to emergence. In 2010–2011 and 2011–2012, 10 replicate rows containing randomized strands of 20 unshelled, uninfested almonds from each variety were placed in the field for both the fall and spring A. transitella flight. The almonds were returned to the lab before the initiation of the second spring A. transitella flight and categorized by presumed cause of damage (bird damage, A. transitella damage, or both types of damage). Damage, variety, and their interaction significantly impacted A. transitella survival and DDs to emergence in male moths. Female moth DDs to emergence were significantly impacted by damage alone. Damage from birds and A. transitella damage were positively correlated, and A. transitella damage associated with bird damage was more common than A. transitella damage alone. Nonconspecific damage may have a significant impact on A. transitella populations in the field, and bird damage may have repercussions beyond its direct impact on marketable yield.

Understanding mating behavioral sequence helps us identify the mechanisms of mate assessment and choice, and better evaluate behavior-based pest control strategies. Here we describe the mating behavior of Cnephasia jactatana Walker whose females release a sex pheromone, and determine the effect of male mating status on reproductive success. The mating sequence starts when males approach females and display courtship behavior with antennation and fanning wings. Both males and females may end a mating attempt at any stage of the sequence. Both sexes assess their mates from the initial contact to copulation. Females appear to be choosier at the early and mid-stages than at the late stage of the sequence. Virgin males approach and court females significantly earlier than nonvirgin males. As compared with nonvirgin males, virgin males are ≈1.6 times more likely to approach and 1.8 times more likely to court females, and four times more likely to achieve mating. This may be attributed to depletion of sperm and accessory gland materials and reduced ability to respond to female sex pheromones in nonvirgin males. The number of attempts by males to acquire mates may be one of the traits that females assess before choosing their mates.

Use of plant secondary metabolic compounds is an important method for insect pest control. In this study, the survival, development, and reproduction of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) MEAM1 cryptic species were compared over two consecutive generations on three cotton cultivars of different gossypol levels. Both cotton cultivar and generation significantly affected the fitness of the whitefly. In both generations, the immature development times on the low-gossypol cultivar ZMS13 were significantly longer than those on the high-gossypol cultivar M9101 or medium-gossypol cultivar HZ401. The female fecundity and rate of population increase of the whitefly ranked in the following order: ZMS13 > HZ401 > M9101. On each cultivar, the immature development time was shorter and the immature survival rate was higher in the second generation than those in the first generation. Rate of increase was also higher in the second generation. These results demonstrated that the fitness of B. tabaci MEAM1 cryptic species on the low-gossypol cotton cultivar ZMS13 was higher than that on the medium- or high-gossypol cultivar. The comparison of the life histories of B. tabaci MEAM1 cryptic species on different cotton varieties is important for the development of an integrated pest management program of the whitefly by using plant secondary metabolic compounds.

Honey bees are the main pollinators of onion crops for seed production, but owing to low attractiveness of flowers, pollination is often inadequate. Pollination problems result in low seed yields. This problem is accentuated when male sterile lines (MSL) are used to produce hybrid onion seeds. In this study, the effect of floral attributes and nectar composition on the preference of honey bees of four MSLs and one onion open pollinated cultivar were assessed. The chemical composition of nectar was described through the analysis of sugars, trace elements, volatile organic compounds, and phenol compounds. The samples studied showed qualitative and quantitative differences in the analyzed traits of flowers and nectar among the different lines. Furthermore, field observations showed a great difference on the number of bee visits and seed yield among the onion lines analyzed. For the first time, this study demonstrates that there are marked differences in the chemical composition of nectar and floral morphology between open pollinated and MSLs and also within MSLs. In addition, these differences were correlated with the number of visits and seed yield. Therefore, it would be possible to select indirectly the most promising productive MSL using simple determinations of chemical compounds or floral morphological characters.

A comparative field study was conducted to evaluate the ability of subterranean termites to damage a set of four different plastic materials (cable sheathings) exposed below- and above-ground. Eight pest species from six countries were included, viz., Coptotermes formosanus (Shiraki) in China, Japan, and the United States; Coptotermes gestroi (Wasmann) in Thailand and Malaysia; Coptotermes curvignathus (Holmgren) and Coptotermes kalshoveni (Kemner) in Malaysia; Coptotermes acinaciformis (Froggatt) with two forms of the species complex and Mastotermes darwiniensis (Froggatt) in Australia; and Reticulitermes flavipes (Kollar) in the United States. Termite species were separated into four tiers relative to decreasing ability to damage plastics. The first tier, most damaging, included C. acinaciformis, mound-building form, and M. darwiniensis, both from tropical Australia. The second tier included C. acinaciformis, tree-nesting form, from temperate Australia and C. kalshoveni from Southeast Asia. The third tier included C. curvignathus and C. gestroi from Southeast Asia and C. formosanus from China, Japan, and the United States, whereas the fourth tier included only R. flavipes, which caused no damage. A consequence of these results is that plastics considered resistant to termite damage in some locations will not be so in others because of differences in the termite fauna, for example, resistant plastics from the United States and Japan will require further testing in Southeast Asia and Australia. However, plastics considered resistant in Australia will be resistant in all other locations.

Bemisia tabaci (Gennadius) biotype B is a highly prolific and polyphagous whitefly that established in much of North America during the 1980s. Neonicotinoid insecticides have been fundamental in regaining control over outbreak populations of B. tabaci, but resistance threatens their sustainability. Susceptibility of B. tabaci in the southwestern United States to four neonicotinoid insecticides varied considerably across populations within each year over a 3 yr period. Using a variability ratio of highest LC₅₀ to lowest LC₅₀ in field-collected whitefly adults from Arizona and California, the ranges of LC₅₀s across all tests within compounds were highest to imidacloprid and lowest to thiamethoxam. Patterns of susceptibility were similar among all four neonicotinoid insecticides, but the greater variability in responses to imidacloprid and significantly higher LC₅₀s attained indicated higher resistance levels to imidacloprid in all field populations. Further evidence of differential toxicities of neonicotinoids was observed in multiple tests of dinotefuran against imidacloprid-resistant lab strains that yielded significant differences in the LC₅₀s of dinotefuran and imidacloprid in simultaneous bioassays. To test the possibility that resistance expression in field-collected insects was sometimes masked by stressful conditions, field strains cultured in a greenhouse without insecticide exposure produced significantly higher LC₅₀s to all neonicotinoids compared with LC₅₀s attained directly from the field. In harsh climates such as the American southwest, resistance expression in field-collected test insects may be strongly influenced by environmental stresses such as high temperatures, overcrowding, and declining host plant quality.

Resistance levels in whitefly, Bemisia tabaci (Gennadius) collections from cotton and sunflower (up to four districts) for five neonicotinoids and two insect growth regulators (IGRs) were investigated for two consecutive years. Based on the LC₅₀s, all collections showed slight to moderate levels of resistance for the tested insecticides compared with the laboratory susceptible population. The data also indicated that cotton and sunflower collections had similar resistance levels. In comparison (four collections), Vehari collections showed higher resistance for acetamiprid, thiacloprid, and nitenpyram compared with those of others. Average resistance ratios for acetamiprid, thiacloprid, and nitenpyram ranged from 5- to 13-, 4- to 8-, and 9- to 13-fold, respectively. Multan and Vehari collections also exhibited moderate levels (9- to 16-fold) of resistance to buprofezin. Furthermore, toxicity of neonicotinoids against immature stages was equal to that of insect growth regulators. The data also suggested that resistance in the field populations was stable. After selection for four generations with bifenthrin (G₁ to G₄), resistance to bifenthrin increased to 14-fold compared with the laboratory susceptible population. Selection also increased resistance to fenpropathrin, lambda-cyhalothrin, imidacloprid, acetamiprid, and diafenthuron. Cross-resistance and stability of resistance in the field populations is of some concern. Rotation of insecticides having no cross-resistance and targeting the control against immature stages may control the resistant insects, simultaneously reducing the selection pressure imposed.

Diamondback moth, Plutella xylostella (L.) is a serious insect pest of vegetables worldwide, and has evolved resistance to various kinds of insecticides. Studies were conducted to determine the baseline toxicity of metaflumizone and the possibility of cross-resistance between metaflumizone and indoxacarb, two sodium channel blocking insecticides (SCBIs), in field populations of P. xylostella from China. The variation in susceptibility to metaflumizone among 29 field populations of P. xylostella collected from 14 geographical locations in China was less than five-fold, with 50% lethal concentrations (LC₅₀s) varying from 1.34 to 6.55 mg/liter. Limited variations in LC₅₀s (less than five-fold, ranging from 1.76 to 8.16 mg/liter) were also observed in the four laboratory-selected strains with high levels of resistance to abamectin, spinosad, fipronil, or Bt toxin Cry1Ac. The toxicity of metaflumizone and indoxacarb was compared among 23 out of the 29 field populations. When compared with the susceptible Roth strain, the JN-09B population showed the highest level of resistance to indoxacarb (110-fold), but two-fold tolerance to metaflumizone. The other 22 populations (with 5- to 58-fold of resistance to indoxacarb) had 1- to three-fold tolerance to metaflumizone. Metaflumizone could provide an effective alternative insecticide for diamondback moth management. Although the field populations of P. xylostella tested with various levels of resistance to indoxacarb did not have cross-resistance to metaflumizone, metaflumizone should be rotated with other chemicals of different modes of action instead of indoxacarb.

Cotton aphid, Aphis gossypii Glover, has a history of developing resistance to novel insecticides. A program is needed to monitor cotton aphid susceptibility to new insecticides. Concentration-mortality bioassays were conducted from 2008 to 2011 to monitor the susceptibility of cotton aphids from fields across the midsouthern United States to thiamethoxam and sulfoxaflor. Flonicamid was included in 2010 and 2011. Bioassays followed the procedures described by the Insecticide Resistance Action Committee for testing neonicotinoids against cotton aphid. Mortality was rated at 48 and 72 h. These bioassays suggest that high levels of resistance to thiamethoxam occur in cotton aphid throughout the midsouthern United States. Resistance ratios ranged from 0.9 to 562.6 at 48 h, and from 0.9 to 29.1 at 72 h. Aphid colonies tested were considered susceptible to flonicamid and sulfoxaflor. The LC₅₀ values ranged from 1.43 to 6.60 ppm for flonicamid. The LC₅₀ values for sulfoxaflor ranged from 1.01 to 5.85 ppm and 0.92–4.13 ppm at 48 and 72 h, respectively. These values represent the baseline variability of the susceptibility of cotton aphid to flonicamid and sulfoxaflor. The moderate level of variability observed combined with the high level of efficacy at low rates and the high reproductive rate of cotton aphid suggests that an effective resistance management plan needs to be devised for these insecticides. Flonicamid and sulfoxaflor should provide effective control of cotton aphid in areas where thiamethoxam resistance occurs. However, these insecticides need to be incorporated into a rotation strategy to preserve their efficacy against cotton aphid.

This study provides a protocol for rapid DNA isolation from psyllid vectors (Bactericera cockerelli and Diaphorina citri) that can be used directly with DNA-based methods for the detection of ‘Candidatus (Ca.) Liberibacter solanacearum,’ the bacterial causal agent of potato zebra chip disease and eventually for ‘Ca. Liberibacter asiaticus’ the causal agent of huanglongbing disease in citrus. The fast DNA extraction protocol was designed to work with conventional polymerase chain reaction (cPCR) DNA amplification as well as Loop mediated PCR DNA amplification. Direct cPCR of the psyllid 28S rDNA gene from samples prepared using the fast DNA extraction method was as reliable as from samples prepared using standard DNA purification (>97% from live insects) as tested in B. cockerelli. However, samples prepared using the fast DNA extraction method had to be diluted 1:100 in sterile water for reliable amplification, presumably to dilute PCR inhibitors in the crude extract. Similarly, both cPCR and loop mediated PCR DNA amplification detected ‘Ca. Liberibacter’ in psyllids infected with either the zebra chip or huanglongbing pathogen equally well from diluted samples prepared using the fast DNA extraction method or from samples prepared using a DNA purification step. In addition to being reliable, the time required to complete the fast DNA extraction for 10 samples was on average ≈5 min and required no special reagents or laboratory equipment. Thus, the fast DNA extraction method shows strong promise as a rapid, reliable, and expedient method when coupled with PCR-based analyses for detection of ‘Ca. Liberibacter’ pathogens in psyllids.

Quantitative real-time reverse transcription polymerase chain reaction is widely used for gene expression analysis, and robust normalization against stably expressed endogenous reference genes (ERGs) is necessary to obtain accurate results. In this study, the stability of nine housekeeping genes of the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) Mediterranean were evaluated in various conditions by quantitative real-time reverse transcription polymerase chain reaction using geNorm and Normfinder programs. Both programs suggested α-tubulin/ubiquitin and 18S small subunit ribosomal RNA the most stable genes for bacterium- and insecticide-treated whiteflies, respectively. For developmental stages, organs, and the samples including salivary glands and the whole body, transcription initiation factor TFIID subunit was calculated as the most stably expressed gene by both programs. In addition, we compared the RNA-seq data with the results of geNorm and Normfinder and found that the stable genes revealed by RNA-seq analysis were also the ERGs recommended by geNorm and Normfinder. Furthermore, the use of the most stable gene suggested by RNA-seq analysis as an ERG produced similar gene expression patterns compared with results generated from the normalization against the most stable gene selected by geNorm and Normfinder and multiple genes recommended by geNorm. It indicates that RNA-seq data are reliable and provide a great source for ERG candidate exploration. Our results benefit future research on gene expression profiles of whiteflies and possibly other organisms.

Fifty-nine sweetpotato cultivars, including 16 heirlooms, 11 near-heirlooms (developed in the 1960s and 1970s), 19 cultivars from the 1980s, and 13 modern varieties (since 1990), were evaluated for resistance to soil insects in field experiments during 2010–2011 at the U.S. Department of Agriculture-Agriculture Research Service, U.S. Vegetable Laboratory (USDA-ARS, USVL), Charleston, SC. These experiments included two insect-susceptible control cultivars (‘Beauregard’ and ‘SC1149-19’) and four insect-resistant control cultivars (‘Charleston Scarlet,’ ‘Regal,’ ‘Ruddy,’ and ‘Sumor’) that were developed by the USDA-ARS, USVL sweetpotato breeding program. Sweetpotato genotypes differed significantly in resistance measured by the overall percentage of injured roots, WDS ( Wireworm, Diabrotica, and Systena) index, the percentage of roots damaged by the sweetpotato weevil (Cylas formicarius F.), the percentage of roots damaged by the sweetpotato flea beetle (Chaetocnema confinis Crotch), and the percentage of roots damaged by white grub larvae (including Plectris aliena Chapin and Phyllophaga spp.). Twenty-three sweetpotato cultivars had a lower percentage of injured roots than the susceptible control genotype, SC1149-19, while 14 varieties had a lower percentage of injured roots than Beauregard, one of the leading commercial orange-fleshed cultivars in the United States. Over the 2-yr period, Ruddy (7.6%) had the lowest percentage of injured roots and ‘Carolina Ruby’ (84.6%) the highest percentage of injured roots. Carolina Ruby (1.07) also had the highest WDS index, but 15 genotypes had a significantly lower WDS index than either susceptible control, SC1149-19 (1.03) or Beauregard (0.82). Ruddy (0.07) and ‘Murasaki-29’ (0.09) had the lowest WDS indices. Forty-five genotypes had a significantly lower percentage infestation by flea beetles than SC1149-19 (12.3%), and the highest level of flea beetle infestation was for ‘Bonita’ (18.9%). The highest percent white grub infestation was for ‘Caromex’ (19.6%), however none of the genotypes had significantly less white grubs than the susceptible controls. The highest infestation of sweetpotato weevils was observed for SC1149-19 (17.9%), while 29 genotypes had significantly lower percentage of sweetpotato weevil infestation than SC1149-19. The moderate to high levels of resistance to soil insect pests exhibited by many of these traditional and heirloom cultivars may provide useful sources of germplasm for sweetpotato breeding programs.

Feeding on above- and belowground plant tissues by Tipula paludosa Meigen during the period of rapid growth from second to forth instars is highly damaging to cool-season (C3) turfgrasses. It may be possible to reduce this damage by identifying grass genotypes that increase host plant protection. This study examined the impacts of plant genotype, endophyte infection, and plant ontogeny on host plant and insect responses during whole-plant feeding by T. paludosa. A series of no-choice greenhouse trials were conducted with third instar crane flies to determine 1) host plant tolerance in terms of reductions to above- and belowground plant biomass, 2) antixenosis resistance impacting insect behavior (emigration), and 3) antibiosis resistance impacting insect growth. Results showed that insect infestation level was the primary factor influencing plant biomass reductions. Belowground tissues were more tolerant to feeding than were aboveground tissues, with tall fescues, Festuca arundinacea Schreber, being most resistant to aboveground biomass reduction. Host plant associations with intercellular fungal endophytes (E ) decreased insect weight gain and decreased insect movement, but did not increase host plant tolerance. Plant ontogeny affected this response with insect weight gain significantly decreased on young (28 d) growth E grasses but not on old (90 d) growth E grasses, however. Host plant genotype and plant ontogeny can have significant impacts to host plant tolerance and insect physiology for T. paludosa larva. Furthermore, plant-endophyte associations have apparent sublethal effects that impact insect fitness and may further enhance host plant protection.

The English grain aphid, Sitobion avenae (F.), is a destructive insect pest of wheat. In this study, wheat germplasm was evaluated for resistance and tolerance to English grain aphid infestation. Except for spikelet number/spike, the 1,000-kernel weight, spike weight, grain weight/ spike, and sterile spikelet number/spike of infested plants were all significantly impacted by English grain aphid infestation. Of 292 wheat accessions, only one genotype showed English grain aphid high resistance, and most genotypes showed intermediate resistance. Tolerance index values ranged widely among all accessions, but 11 genotypes had high tolerance to English grain aphid. Different resistance and tolerance parameters were positively correlated. Five green bug-resistant genotypes had a betterEnglish grain aphid tolerance index than other genotypes. Eleven genotypes exhibited a high or moderate level of tolerance and moderate level of resistance to English grain aphid. The broad-sense heritability of 1,000-kernel weight loss rate and peak aphid density were also estimated. English grain aphid resistant and tolerant lines identified in our study will be helpful in future breeding programs.

While soybean cultivars with resistance to the soybean aphid (Aphis glycines Matsumura) have been commercially released, the presence of virulent biotypes capable of overcoming plant resistance threatens the durability of host plant resistance as a stable management tactic. Novel sources of host plant resistance are needed to combat rapid biotype evolution. In this study, we screened 1,061 soybean plant introductions (PIs) for resistance to three known biotypes of A. glycines. Based on a series of growth chamber and field screenings, we identified 11 PIs that showed resistance to biotype 1 of A. glycines. Among these 11 PIs, 7 PIs were resistant to biotype 2 and 5 PIs were resistant to biotype 3. Further, two PIs (PI 606390A from Vietnam and PI 340034 from South Korea) showed resistance to all three biotypes of A. glycines. We also identified 11 PIs that were potentially tolerant to A. glycines, illustrated by no adverse impact on plant quality because of A. glycines infestation. As resistant PIs identified in this study belong to maturity group II–IV, they can be readily crossed to early maturing cultivars adapted to north-central states of the United States, where A. glycines is a major pest. The genetic characterization of resistance in these PIs and incorporation of novel resistant genes into elite soybean cultivars will broaden the defense against multiple biotypes of A. glycines.

Phenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is an invasive mealybug of Neotropical origin. In recent years it has invaded the Mediterranean Basin causing significant damages in bougainvillea and other ornamental plants. This article examines its phenology, location on the plant and spatial distribution, and presents a sampling plan to determine P. peruvianus population density for the management of this mealybug in southern Europe. Six urban green spaces with bougainvillea plants were periodically surveyed between March 2008 and September 2010 in eastern Spain, sampling bracts, leaves, and twigs. Our results show that P. peruvianus abundance was high in spring and summer, declining to almost undetectable levels in autumn and winter. The mealybugs showed a preference for settling on bracts and there were no significant migrations between plant organs. P. peruvianus showed a highly aggregated distribution on bracts, leaves, and twigs. We recommend a binomial sampling of 200 leaves and an action threshold of 55% infested leaves for integrated pest management purposes on urban landscapes and enumerative sampling for ornamental nursery management and additional biological studies.

Monitoring the distribution and abundance of an invasive species is challenging, especially during the initial years of spread when population densities are low and basic biology and monitoring methods are being investigated. Brown marmorated stink bug (Halyomorpha halys (Stål)) is an invasive agricultural and urban pest that was first detected in the United States in the late 1990s. At the time of its detection, no method was available to effectively track H. halys populations, which are highly mobile and polyphagous. One possible solution was the utilization of black light traps, which are nonspecific traps attractive to night flying insects. To determine if black light traps are a reliable monitoring tool for H. halys, a state-wide network of 40–75 traps located on New Jersey farms were monitored from 2004 to 2011 for H. halys. This proved to be a highly effective method of monitoring H. halys populations and their spread at the landscape level. The total number of brown marmorated stink bug caught in New Jersey increased exponentially during this period at a rate of 75% per year. Logistic regression estimates that 2.84 new farms are invaded each year by H. halys. The results indicate that black light traps are attractive to early season populations as well as at low population densities. Weekly trap catch data are being used to generate state-wide population distribution maps made available to farmers in weekly newsletters and online. While no economic threshold currently exists for brown marmorated stink bug, the maps provide farmers with a tool to forecast pest pressure and plan management.

Economic evaluations of integrated pest management strategies are becoming increasingly important as restrictions on conventional insecticides continue to become more stringent and chemical control costs rise. Aerosol treatments with insect growth regulators alone and in combination with conventional contact insecticides may be a feasible alternative to expensive and highly toxic fumigants such as methyl bromide for control of the Indianmeal moth (Plodia interpunctella (Hübner)). Average calculated mortality of Indianmeal moth eggs exposed to surface applied methoprene, aerosol methoprene alone and in combination with esfenvalerate and synergized Pyrethrins is 55.0, 69.0, and 94.6%, respectively. Temperature effects on development time makes frequency and timing of insecticide applications very important as evidenced by simulations of population levels in response to a variety of treatment dates by diet, and become critical in situations where survival of Indianmeal moth is high. Using a measurement of risk that is equal to deviations below a target mortality goal (99%), we are able to optimize cost and frequency of application using simulated mortality data for each of the treatment strategies. Optimal timing of each insecticide treatment depends heavily on the rate of development by diet. This type of analysis helps pest control operators and managers by showing consequences of treatment scenarios in time and cost.

The apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), is a serious introduced quarantine pest in the apple (Malus spp.)-growing regions of central Washington and Oregon. In August 2011, seven fly larvae of unknown origin were discovered infesting fruit of an exotic Chinese crabapple, Malus spectabilis (Aiton) Borkhausen, in Kennewick, Benton County, WA. If confirmed, Chinese crabapple would have represented a new host for R. pomonella in Washington and triggered quarantine measures in a surrounding three-county region of the state. Here, we establish, based on five microsatellite loci, the identity of the crabapple-infesting larvae as the western cherry fruit fly, Rhagoletis indifferens Curran, representing a new host record for the fly. Morphological analysis of six flies reared to adulthood confirmed the genetic identification. The results demonstrate the utility of integrating rapid genetic identification methods with field surveys of economic pests, which decreased detection times by months, and avoided enacting costly quarantine measures that saved local and federal bodies >US$0.5 million in monitoring, inspection, and control costs. We discuss current ongoing efforts to develop rapid, accurate, and inexpensive on site DNA-based detection tools for R. pomonella that would have general applicability for the control of pest insects.