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Currently, domestic production of vegetable soybean (aka “edamame”) lags well behind consumer demand, with approximately 70% of U.S.-consumed edamame imported each year. A major barrier for growth of the U.S. edamame industry is an overall lack of varieties with adequate consumer acceptability and adaption to the U.S. climate and environment. In this study, we evaluated eleven vegetable soybean genotypes (including one commercial check) for differences in yield, pod size, and resistance to local insect, bacterial, and fungal pressures in order to identify genotypes with the greatest potential for use in commercial edamame production. Although there were variations in average pod length (42.1 - 53.6 mm), width (10.9 - 12.7 mm), and thickness (6.29 - 7.34 mm) among the genotypes, only pod length showed statistical significance. In addition, genotype significantly affected fresh pod yield. The prevalence of specific insect pests varied by location and year and included soybean aphid, potato leafhopper, Mexican bean beetle, as well as a complex of stink bugs and lepidopteran larvae. For each of these insect pests, significant differences were observed. Some plant diseases observed on the edamame genotypes included: downy mildew, bacterial pustule, Fusarium pod rot, Cercospora blight and purple seed stain, and damping off. In 2018, in Whitethorne, VA, soybean downy mildew was quite prevalent and disease symptoms varied considerably. Overall, genotypes V16-0524 and R15-10280 showed particularly favorable yield, and resilience to native pests compared to the commercial check, UA-Kirksey. The genotypes V16-0524 and R15-10280 showed strong potential to increase the availability of varieties that can be used for commercial edamame production in the Mid-Atlantic region.

The squash bug, Anasa tristis (De Geer), is a serious pest of cucurbit crops across the United States, especially within summer squash (Cucurbita pepo L.) systems. Using their piercing sucking mouthparts, squash bugs feed on both leaf tissue and fruits, often leading to leaf necrosis, marketable fruit loss, and even plant death. To date, the relationship between squash bug presence and plasticulture has not been adequately investigated. This 2-yr study evaluated the effects of white, black, and reflective plastic mulch colors on the occurrence of all squash bug life stages and marketable zucchini yield in Virginia. In both years, A. tristis adults and egg masses were more numerous on zucchini plants grown in white and reflective plastic mulch compared to bare ground plants. Greater nymphal densities and marketable fruit yield were observed in certain plastic mulch treatments versus the bare ground treatment, yet these differences were not consistent in both years. Contrary to the repellency effects reflective mulches have on other cucurbit insect pests, our research suggests that reflective and other plastic mulch colors can negatively impact squash bug management, especially in regions with high A. tristis pressure. Our study offers new insights for cucurbit growers to use when considering whether they should implement plasticulture in their growing systems. Southern Sustainable Agriculture Research and Education (SARE) grant [LS20-337] Published version We would like to thank the graduate and undergraduate students of the Kuhar lab in the Department of Entomology at Virginia Tech for their help with field site preparation, insect sampling, and zucchini harvesting. We also thank the Kentland Research Farm and Homefield Farm staff for their contributions to field site preparation and vegetable cultivation. This study was funded by Southern Sustainable Agriculture Research and Education (SARE) grant #LS20-337. Public domain – authored by a U.S. government employee

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

Corn rootworm remains the key pest of maize in the United States. It is managed largely by Bt corn hybrids, along with soil insecticides and neonicotinoid seed treatments (NSTs), the latter of which are applied to virtually all conventionally (non-Bt) produced maize. Frequently, more than one of these pest-management approaches is employed at the same time. To determine the utility and relative contributions of these various approaches, a meta-analysis was conducted on plant health and pest damage metrics from 15 yr of insecticide efficacy trials conducted on Indiana maize to compare the pest-protection potential of NSTs to that of other insecticides and Bt hybrids. The probability of recovering the insecticide cost associated with each treatment was also calculated when possible. With the exception of early-season plant health (stand counts), in which the NSTs performed better than all other insecticides, the vast majority of insecticides performed similarly in all plant health metrics, including yield. Furthermore, all tested insecticides (including NSTs) reported a high probability (>80%) of recovering treatment costs. Given the similarity in performance and probability of recovering treatment costs, we suggest NSTs be optional for producers, so that they can be incorporated into an insecticide rotation when managing for corn rootworm, the primary Indiana corn pest. This approach could simultaneously reduce costs to growers, lower the likelihood of nontarget effects, and reduce the risk of pests evolving resistance to the neonicotinoid insecticides.

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

Spotted knapweed, Centaurea stoebe L. (Asteraceae), is an invasive perennial forb that has become economically and ecologically damaging in North America. The weevil Larinus minutus Gyllenhal (Coleoptera: Curculionidae), a biological control agent of invasive knapweeds, was introduced to 37 sites in northwest Arkansas since 2008 as part of a biological control program for spotted knapweed. In 2011 and 2012, 25 of these release sites were surveyed to monitor how L. minutus infestation rates changed in relation to distance and time from release. The initial L. minutus introductions at these sites occurred from 2008 to 2011. Transects were used from the point of initial weevil introduction to establish sampling quadrats in which capitula were collected to document weevil presence and infestation rates. The mean maximum distance of weevil colonization and mean local abundance (within the first 50 m from the release point) were calculated in relation to time (yr) since release. Five sites had > 10 quadrats in both sampling years and were analyzed with an exponential decay function to model localized population growth and spread. Annual increases in mean local abundance and maximum distance of colonization were observed. These results were substantiated by localized growth (at 3 sites) and spread (at 2 sites) that occurred at the 5 sites analyzed with the exponential decay function. These findings suggest that in years following L. minutus introduction, assuming similar release strategies and environmental conditions, consistent increases in weevil infestation rates and spread from the release site may be expected in about half the sites at which populations establish. USDA-APHIS-PPQUnited States Department of Agriculture (USDA) We thank Edward Gbur Jr. and Fred Stephen for their input on experimental design, and Elizabeth Long for her feedback on the manuscript. This work was supported in part through a Cooperative Agreement with USDA-APHIS-PPQ.

Neonicotinoid seed treatments, typically clothianidin or thiamethoxam, are routinely applied to >80% of maize (corn) seed grown in North America where they are marketed as a targeted pesticide delivery system. Despite this widespread use, the amount of compound translocated into plant tissue from the initial seed treatment to provide protection has not been reported. Our two year field study compared concentrations of clothianidin seed treatments in maize to that of maize without neonicotinoid seed treatments and found neonicotinoids present in root tissues up to 34 days post planting. Plant-bound clothianidin concentrations followed an exponential decay pattern with initially high values followed by a rapid decrease within the first ~20 days post planting. A maximum of 1.34% of the initial seed treatment was successfully recovered from plant tissues in both study years and a maximum of 0.26% was recovered from root tissue. Our findings show neonicotinoid seed treatments may provide protection from some early season secondary maize pests. However, the proportion of the neonicotinoid seed treatment clothianidin translocated into plant tissues throughout the growing season is low overall and this observation may provide a mechanism to explain reports of inconsistent efficacy of this pest management approach and increasing detections of environmental neonicotinoids.

A 2-year, multi-state study was conducted to assess the benefits of using soybean seed treated with the neonicotinoid thiamethoxam to manage soybean aphid in the upper Midwestern USA and compare this approach with an integrated pest management (IPM) approach that included monitoring soybean aphids and treating with foliar-applied insecticide only when the economic threshold was reached. Concentrations of thiamethoxam in soybean foliage were also quantified throughout the growing season to estimate the pest management window afforded by insecticidal seed treatments.Both the IPM treatment and thiamethoxam-treated seed resulted in significant reductions in cumulative aphid days when soybean aphid populations reached threshold levels. However, only the IPM treatment resulted in significant yield increases. Analysis of soybean foliage from thiamethoxam-treated seeds indicated that tissue concentrations of thiamethoxam were statistically similar to plants grown from untreated seeds beginning at the V2 growth stage, indicating that the period of pest suppression for soybean aphid is likely to be relatively short.These data demonstrate that an IPM approach, combining scouting and foliar-applied insecticide where necessary, remains the best option for treatment of soybean aphids, both in terms of protecting the yield potential of the crop and of break-even probability for producers. Furthermore, we found that thiamethoxam concentrations in foliage are unlikely to effectively manage soybean aphids for most of the pests' activity period across the region. © 2017 Society of Chemical Industry.