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Brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive pest of Asian origin first detected in North Carolina in 2009. By 2015, it became an important pest in the mountain and Piedmont regions, but its population densities have remained low in the eastern plains regions. Starting with a cohort of diapausing adults in January of 2018 and 2019, semi-field cage studies were used to document the phenology and reproductive capacity of H. halys through October of each year at Mills River (mountains) and Goldsboro (Southeastern Plains) sites, which have the same photoperiod, but different temperature profiles. Halyomorpha halys was univoltine in the cooler mountain site, but bivoltine in the warmer plains site, leading to earlier emergence from overwintering diapause, greater heat unit accumulations, and a F1 adult generation that emerged before on-set of diapause-inducing conditions, which allowed for an F2 generation. However, only 17.2% of ovipositing F1 females laid egg masses that hatched, compared to > 90% of overwintered females. Poor establishment of H. halys in the plains versus mountains was attributed to heat stress that contributed to a higher percentage of overwintered adults that emerged early and did not oviposit, a truncated oviposition pattern by overwintered adults, and poor F2 egg hatch. Quadratic equations fit relationships between cumulative degree-days from biofix and proportional oviposition and adult eclosion of respective generations. Utility of the phenology model on a wider scale will depend on how well H. halys populations in other areas conform to North Carolina population's response to photoperiod and temperature. [ABSTRACT FROM AUTHOR]

Hexanoic acid, 1-octanol, 1,8-octanediol, octyl hexanoate, 1,8-octanediol monohexanoate, and 1,8-octanediol dihexanoate were identified in headspace volatiles collected from the crushed abdomen of a female click beetle of the species Parallelostethus attenuatus (Say) (Elaterinae, tribe Elaterini). In field trials carried out in Illinois, South Carolina, North Carolina, and Virginia, adult male beetles were strongly attracted to 1,8-octanediol dihexanoate alone. Blends of the dihexanoate with one or more of the other compounds proved to be less attractive than the dihexanoate alone, suggesting that the pheromone of this species may consist of a single compound. The symmetrical diester structure of the pheromone is a novel natural product and appears to be structurally unique among insect pheromones. [ABSTRACT FROM AUTHOR]

Crop production sequences influence arthropod populations in temporally unstable row crop systems. Winter wheat (Triticum aestivum L.) represents one of the earliest abundant crops in south‐eastern United States. This study aims to understand primary source habitats driving brown stink bug, Euschistus servus (Say), and tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), population abundance in wheat.To better understand these relationships, adult and nymphal densities were in wheat fields weekly from flowering through harvest in 2019 and 2020. Geospatial data were used to measure landscape composition surrounding sampled fields. We investigated the influence of landscape predictors on E. servus and L. lineolaris abundance using generalized linear mixed modelling.Field size, proportion of agriculture, proportion of wheat area, and proportion of soybean Glycine max L.) area from the previous year in the surrounding landscape were associated with E. servus abundance in wheat. Similarly, L. lineolaris abundance was associated with proportion of wheat area and soybean area from the previous year.These results reveal the influence of soybean area planted the previous year on insect pest densities the following spring in wheat. Further, results suggest agricultural landscapes dominated by wheat are associated with decreased pest abundance across the sampled region. [ABSTRACT FROM AUTHOR]

Melanotus communis Gyllenhal (Coleoptera: Elateridae) larvae are a common soil-dwelling pest of many crops, including sweet potato, grains, and tobacco. Although many studies have focused on the larval stage of this pest, the seasonal activity and ecology of the adults (click beetles) are not well understood. The overarching goal of this study was to relate M. communis adult activity to host crops in the North Carolina row-crop agroecosystem. To do this, we conducted a two-year study documenting male M. communis activity, using a recently identified sex attractant pheromone, 13-tetradecenyl acetate. This project was divided into two parts: 1) a pheromone assessment study testing the efficacy and specificity of 13-tetradecenyl acetate, and two analogs, 13-tetradecenyl butyrate and 13-tetradecenyl hexanoate, and 2) a landscape survey using traps baited with 13-tetradecenyl acetate. Results of the efficacy study showed that 13-tetradecenyl acetate was the most effective M. communis lure when compared to non-baited control traps or traps baited with the two homologs. The landscape study documented a strong association between M. communis catch and the adjacent crop type. We found that adult M. communis abundance was greatest near corn, followed by sweet potato, and then cotton. Analysis of activity over time found that the peak activity occurred during July. Overall, this project demonstrates the usefulness of pheromone-baited traps in providing new information about M. communis activity. [ABSTRACT FROM AUTHOR]

North Carolina is the largest producer of sweetpotato (Ipomoea batatus L.) in the United States but only a small percentage of total production is organic. Transition to organic sweetpotato production has been limited, in part due to a lack of effective non-chemical strategies to control wireworms (Coleoptera: Elateridae). To help bridge this knowledge gap, this study focused on documenting the relationship between wireworm damage to sweetpotato roots and the use of cover crops, a common way to maintain soil health in organic production. This study also tested a wireworm-resistant variety (Monaco) against the widely cultivated susceptible variety (Covington). Two different field studies were used to test the interaction between cover crops and insect-resistant sweetpotato varieties. We first examined a reduced-till cover crop system where cover crop residue remained on the soil surface when transplanting sweetpotato. The following year, we tested a fully incorporated cover crop system with spring termination and intensive tillage before sweetpotato transplanting. To complement these field studies, a greenhouse experiment was conducted to compare the efficacy of the wireworm-resistant variety with two susceptible sweetpotato varieties. Results show that varietal resistance had a strong effect on the amount of wireworm damage observed, with susceptible sweetpotato having more direct wireworm damage than the resistant variety. The effect of the cover crop was not found to be significant in any trial. This study provides important context about the role of varietal resistance in organic production and relatively low risk of cover crop use. [ABSTRACT FROM AUTHOR]

Ceratocystis fimbriata, the causal agent of sweetpotato black rot, is a pathogen capable of developing and spreading within postharvest settings. A survey of North Carolina sweetpotato storage facilities was conducted to determine the arthropods present and identify potential vectors of C. fimbriata. Sixteen taxonomic categories were recovered, and the genus Drosophila (Diptera: Drosophilidae) accounted for 79% of individuals sampled, with Drosophila hydei being the most abundant species. Behavioral assays were conducted to determine if D. hydei is attracted to C. fimbriata-inoculated roots and if the pathogen could be recovered from external or intornal surfaces of the insect. Flles were released in insect-trapping pitchers containing either C. fimbriata-inoculated or noninoculated roots or Petri dishes. No significant differences in fly number were detected in sweetpotato-baited pitchers; however, significant differences were found in the pitcher baited with a mature C. fimbriata culture. Flies were subjected to washes to determine if viable C. fimbriata was present (internally or externally); washes were plated onto carrot agar plates and observed for the presence of C. fimbriata colonies. Both external and internal washes had viable C. fimbriata inocula with no significant differences, and inoculated sweetpotatoes had a significantly higher number of flies carrying C. fimbriata. This study suggests that D. hydei can carry C. fimbriata from infected sweetpotatoes and move viable C. fimbriata inocula both externally and internally, making this the first report of any Drosophila sp. serving as a potential vector for the Ceratocystis genus. [ABSTRACT FROM AUTHOR]

The timing and location of Lygus lineolaris (Palisot de Beauvois) dispersal into cotton is important to accurate and effective scouting and management. In the spring, L. lineolaris populations develop on non-crop weeds surrounding cotton fields. As weeds senesce, L. lineolaris migrate into susceptible cotton at the squaring stage. Given this predictable temporal colonization pattern, scouting efforts to inform insecticide interventions may be improved with a spatiotemporally targeted sampling recommendation. Using a geospatial approach, we tracked L. lineolaris populations at 352 unique sites along transects located in commercial North Carolina cotton fields over two consecutive years. Standardized sweep samples of L. lineolaris adults and nymphs were taken at each site. To relate the abundance of L. lineolaris to the spatial structure of cotton fields, the distance of the sample from the field edge and the edge-to-area ratio of each field were analyzed using GIS. All counts were related to accumulated degree days at each sample time to document seasonal progression of L. lineolaris abundance and temporal host utilization (i.e., weeds vs. cotton). Counts were also related to spatially structured scouting recommendations used in North Carolina. Nymph counts were significantly affected by accumulated degree days and distance from field edge. Higher adult counts were found in fragmented fields with greater edge-to-area ratios. Our results show that L. lineolaris nymphs were more spatiotemporally variable than adults, thereby being more likely to affect scouting accuracy when using sweep samples alone. We found that samples closer to the field edge likely increase the probability of being over the North Carolina L. lineolaris threshold. • L. lineolaris nymphs exhibit greater spatiotemporal variation than adults. • L. lineolaris nymphs are found in higher numbers near the field periphery. • L. lineolaris nymph numbers correlate positively with degree-day accumulation. • Fields with a higher perimeter-to-area ratio may be at higher risk of L. lineolaris. • Spatially structured scouting may stabilize variance associated with field edges. [ABSTRACT FROM AUTHOR]

Geospatial models are crucial for identifying likely 'hot-spots' of Bt resistance evolution in Helicoverpa zea (Lepidoptera: Noctuidae), thereby improving regional insecticide resistance management (IRM) strategies and planted refuge compliance. To characterize H. zea distributions in relation to land use , we used historical trapping data collected from 2008 to 2019 in North Carolina to model the spatial and temporal abundance of H. zea populations across Bt -dominated landscapes. Helicoverpa zea abundance was standardized across site-year observations, and candidate landscape composition and configuration predictors of H. zea abundance were obtained. Spatiotemporal Bayesian hierarchical models were developed to make posterior predictions of H. zea abundance from environmental covariates, and results were used to generate interpolation prediction maps to visualize H. zea abundance across the sampled region. Our results suggest inverse distance weighted (IDW) soybeans is the most important predictor of H. zea abundance through time in row crop agroecosystems in North Carolina. Soybeans in North Carolina and southeastern U.S. likely serves as a critical non- Bt refuge for delaying H. zea resistance to Bt toxins in landscapes dominated by Bt maize and cotton. Moreover, soybean abundance can be used to predict the spatial abundance of H. zea in this region. Results can be applied to understand population dynamics of H. zea in landscapes dominated by genetically engineered (GE) crops expressing Bt toxins and will enable the development of sound insect resistance management strategies of H. zea populations to GE toxins targeting noctuid pests of maize and cotton. This work will also drive future geospatial studies investigating environmental predictors of resistance evolution in arthropod pests to GE technologies in crop production systems. Landscape-level variation in soybeans predicts spatial and temporal Helicoverpa zea abundance and likely serves as important non- Bt refugia in maize and cotton agroecosystems. [Display omitted] • Helicoverpa zea population dynamics in row crops relate to landscape drivers • Landscape-level soybean and cotton variation in the southeastern U.S. associate with increased H. zea abundance through time • Soybeans likely serve as critical non- Bt refugia for delaying H. zea resistance in maize and cotton agroecosystems [ABSTRACT FROM AUTHOR]

Root-knot nematodes (RKNs, Meloidogyne spp.) are some of the most economically important and common plant parasitic nematodes in North Carolina (NC) cropping systems. Soil samples collected from fields planted with crops rotated with sweetpotato ( Ipomoea batatas [L.] Lam.) in 39 NC counties in 2015 to 2018 were processed at the NC Nematode Assay Laboratory. The occurrence of second-stage juvenile (J2) RKN populations was examined based on collection year, month, county, and previous planted crop. The highest number of RKN-positive samples originated from Cumberland (53%), Sampson (48%), and Johnston (48%) counties. The highest average RKN population density was detected in Sampson (147 J2/500 cm 3 of soil) and Nash (135 J2/500 cm 3 of soil) counties, while Wayne (7 J2/500 cm 3 of soil) and Greene (11 J2/500 cm 3 of soil) counties had the lowest average RKN population density. Meloidogyne enterolobii is a new invasive species that is impacting sweetpotato growers of NC. The host status of an NC population of M. enterolobii , the guava RKN, was determined by examining eggs per gram of fresh root (ER) and the final nematode egg population divided by the initial population egg count (reproductive factor, RF) in greenhouse experiments. This included 18 vegetable, field, and cover crops and weed species. The tomato 'Rutgers' was used as a susceptible control. Cabbage 'Stonehead', pepper 'Red Bull', and watermelon 'Charleston Gray' and 'Fascination' were hosts and had similar mean ER values to the positive control, ranging from 64 to 18,717. Among field crops, cotton, soybean 'P5018RX', and tobacco were hosts with ER values that ranged from 185 to 706. Members of the Poaceae family such as sweet corn ( Zea mays ) and sudangrass ( Sorghum × drummondii ) were nonhosts to M. enterolobii , and the mean ER values ranged from 1.85 to 7. The peanut 'Tifguard' and winter wheat ( Triticum aestivum ) also had lower ER values than the vegetable hosts. Growers should consider planting less susceptible hosts or nonhosts such as peanut, sudangrass, sweet corn, and winter wheat in 2- to 3-year crop rotations to lower populations of this invasive nematode., Competing Interests: The author(s) declare no conflict of interest.

Evidence of practical resistance of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) to Bt cotton in the United States is debatable, supported with occasional reports of boll damage in the field. Our objective was to provide both empirical and long-term observational evidence of practical resistance by linking both in-season and end-of-season measurements of H. zea damage to pyramided Bt cotton bolls and to provide Cry1Ac diet-based bioassay data in support of these damage estimates. In-season boll damage from H. zea was highly correlated to end-of-season damaged bolls. Across North Carolina, Bt cotton fields with end-of-season bolls damaged by H. zea increased during 2016 compared to previous years. Elevated damage was coupled with an increase in field sprays targeting H. zea during 2016, but not related to an increase in H. zea abundance. Bioassay data indicated that there was a range of Cry1Ac susceptibility across the southeastern United States. Given the range of susceptibility to Cry1Ac across the southeastern United States, it is probable that resistant populations are common. Since H. zea is resistant to cotton expressing pyramided Cry toxins, the adoption of new cotton varieties expressing Vip3Aa will be rapid. Efforts should be made to delay resistance of H. zea to the Vip3Aa toxin to avoid foliar insecticide use., (© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)