Seth Dorman

Agricultural Research Service | ARS

BACKGROUND Economically damaging infestations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), have become more frequent in Virginia and North Carolina cotton since 2013 and 2010, respectively. Foliar insecticide use has increased dramatically in response. Efficacy data (LC50) are needed to evaluate L. lineolaris susceptibility a...

BACKGROUND Resistance evolution of lepidopteran pests to Bacillus thuringiensis (Bt) toxins produced in maize and cotton is a significant issue worldwide. Effective toxin stewardship requires reliable detection of field‐evolved resistance to enable the implementation of mitigation strategies. Currently, visual estimates of maize injury are used to...

BACKGROUND Helicoverpa zea (Boddie) damage to Bt cotton and maize has increased as a result of widespread Bt resistance across the USA Cotton Belt. Our objective was to link Bt crop production patterns to cotton damage through a series of spatial and temporal surveys of commercial fields to understand how Bt crop production relates to greater than...

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...

Red clover casebearer moth (Coleophora deauratella) (Leinig and Zeller) (Lepidoptera: Coleophoridae) is an invasive insect pest in red clover (Trifolium pratense L.) seed production systems in North America and New Zealand. Recent discoveries of C. deauratella in Oregon and New Zealand prompted research investigating the seasonal phenology and popu...

The clover seed weevil, Tychius picirostris Fabricius (Coleoptera: Curculionidae), is a major pest in Oregon white clover seed crops. Reliance on synthetic pyrethroid insecticides and limited availability of diverse modes of action (MoAs) has increased insecticide resistance selection in regional T. picirostris populations, emphasizing the need to...

The subterranean sod webworm, also known as cranberry girdler (Chrysoteuchia topiaria), is one of the most damaging insect pests in cool‐season grass grown for seed crops in Oregon. Chemical control options are limited and require irrigation or rainfall for adequate insecticide incorporation to control C. topiaria larvae. Epichloë endophytes associ...

Yellow Dwarf Viruses (YDV) spread by aphids are some of the most economically important barley (Hordeum vulgare L.) virus-vector complexes worldwide. Detection and control of these viruses are critical components in the production of barley, wheat, and numerous other grasses of agricultural importance. Genetic control of plant diseases is often pre...

Oregon produces 70% of the world's cool-season grass seed, many species of which are susceptible to yellow dwarf viruses (YDVs). This virus complex has numerous defined virus species vectored by multiple aphid species. The diversity of YDVs associated with Oregon grass seed production has not been determined and is needed to provide insight to deve...

Red clover (Trifolium pratense L.), a perennial forage legume belonging to the Fabaceae family, is grown for seed in many temperate regions of the world. Coleophora deauratella Leinig and Zeller (Lepidoptera: Coleophoridae) is a significant insect pest occurring globally in several primary red clover seed-producing regions. Coleophora deauratella i...

Oregon’s grass seed industry specializes in the production of forage grasses, including annual ryegrass (Lolium multiflorum) and orchardgrass (Dactylis glomerata). These species are hosts of seed gall nematodes (SGN): Anguina funesta and Anguina sp. SGN cause yield-limiting seed galls and can also vector toxic Rathayibacter bacteria. Trade partners...

The clover seed weevil, Tychius picirostris Fabricius, a serious pest of white clover, Trifolium repens L., grown for seed in western Oregon, causing feeding damage to flowers and developing seeds. Since 2017, white clover seed producers have anecdotally reported T. picirostris control failures using foliar pyrethroid insecticide applications. This...

Overwintering success is an important determinant of arthropod populations that must be considered as climate change continues to influence the spatiotemporal population dynamics of agricultural pests. Using a long-term monitoring database and biologically relevant overwintering zones, we modeled the annual and seasonal population dynamics of a com...

Frankliniella fusca Hinds (Thysanoptera: Thripidae) is an economically important pest of many cultivated crops including cotton, tomatoes, peppers and tobacco. Previous research has focused on the importance of non‐crop weeds for F. fusca populations when estimating crop infestation risk in the spring. Although weeds play an integral role in popula...

Tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), is an economically damaging pest in cotton production systems across the southern United States. We systematically scouted 120 commercial cotton fields across five southeastern states during susceptible growth stages in 2019 and 2020 to investigate sampling optimization and the effect of i...

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...

• 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...

Economic yield loss and reduction in grain quality from brown stink bug, Euschistus servus (Say), feeding injury in early and late stages of maize, Zea mays (Poales: Poaceae, Linnaeus), development was assessed in Virginia and North Carolina in 2018 and 2019. Varying levels of stink bug infestations were introduced to seedling maize (V2—early stage...

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is an important insect pest in cotton that feeds on reproductive fruit, contributing to yield loss. Economically damaging infestations of L. lineolaris have doubled in Virginia since 2013. Escalation of L. lineolaris abundance may increase Fusarium hardlock disease observed in this re...

Economically damaging infestations of Lygus lineolaris (Palisot de Beauvois), tarnished plant bug, were sporadic in Virginia and North Carolina cotton before 2010. Given the sudden rise of L. lineolaris as an economic pest in these states, regionally specific management practices (i.e., chemical and cultural control) are needed to help producers pr...

Lygus lineolaris populations have become increasingly problematic in Virginia cotton since 2013. Although production practices have changed, changes in landscape composition and climatic conditions are also anecdotally associated with increasing populations. To better understand the recent increase in L. lineolaris infestations in Virginia cotton,...

The brown marmorated stink bug, Halyomorpha halys (Stål), is a polyphagous pest that feeds on a wide variety of agricultural commodities including tree fruits, berries, vegetables, field crops, and ornamental trees and shrubs. Accurate knowledge of where H. halys lays eggs is critical to optimize the potential release of Trissolcus japonicus (Ashme...

Insecticide use targeting TPB in Virginia cotton has increased since 2013. To better understand the efficacy of various insecticides available for TPB management in Virginia cotton systems, selected foliar broadcast-applied insecticides were evaluated in 2017 and 2018 at the Virginia Tech Tidewater Agricultural Research and Extension Center in Suff...

Economically damaging infestations of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), the tarnished plant bug, have been increasing in North Carolina and Virginia cotton since 2009. We conducted experiments to compare prophylactically timed sprays based on cotton phenology and current action thresholds based on sweep net and drop cloth...

Hemlock woolly adelgid (HWA), Adelges tsugae Annand, is a highly destructive non-native pest lethal to eastern hemlock, Tsuga canadensis (L.) Carrière, and Carolina hemlock, T. caroliniana Engelmann. Fifty years following the first observation of HWA in eastern North America, a predatory beetle, Laricobius nigrinus Fender, was evaluated, approved,...