Thomas P. Kuhar

Biology, Ecology, and Management of Brown Marmorated Stink Bug (Hemiptera: Pentatomidae)

Brown marmorated stink bug, Halyomorpha halys Stal, is an invasive, herbivorous insect species that was accidentally introduced to the United States from Asia. First discovered in Allentown, PA, in 1996, H. halys has now been reported from at least 40 states in the United States. Additional invasions have been detected in Canada, Switzerland, France, Germany, Italy, and Lichtenstein, suggesting this invasive species could emerge as a cosmopolitan pest species. In its native range, H. halys is classified as an outbreak pest; however, in North America, H. halys has become a major agricultural pest across a wide range of commodities. H. halys is a generalist herbivore, capable of consuming >100 different species of host plants, often resulting in substantial economic damage; its feeding damage resulted in US

Survey of Stink Bug (Hemiptera: Pentatomidae) Egg Parasitoids in Wheat, Soybean, and Vegetable Crops in Southeast Virginia

37 million of losses in apple in 2010, but this stink bug species also attacks other fruit, vegetable, field crop, and ornamental plant species. H. halys has disrupted integrated pest management programs for multiple cropping systems. Pesticide applications, including broad-spectrum insecticides, have increased in response to H. halys infestations, potentially negatively influencing populations of beneficial arthropods and increasing secondary pest outbreaks. H. halys is also challenging because it affects homeowners as a nuisance pest; the bug tends to overwinter in homes and outbuildings. Although more research is required to better understand the ecology and biology of H. halys , we present its life history, host plant damage, and the management options available for this invasive pest species.

Life Table Studies of European Corn Borer (Lepidoptera: Crambidae) with and without Inoculative Releases of Trichogramma ostriniae (Hymenoptera: Trichogrammatidae)

ABSTRACT Stink bugs (Hemiptera: Pentatomidae) cause significant damage to many different crops and horticultural commodities in Virginia. However, little is known about the species diversity or impact of stink bug egg parasitoids in the state. A survey was conducted in 2005 and 2006 (May through September) in wheat (Triticum aestivum L.), soybean (Glycine max L.), and several vegetable crops by collecting natural egg masses of various stink bug species and by monitoring sentinel egg masses. A total of 570 Euschistus servus (Say) eggs in 26 egg masses, 11,197 Murgantia histrionica (Hahn) eggs in 939 egg masses, 15 Podisus maculiventris (Say) eggs in 2 egg masses, and 546 Acrosternum hilare (Say) eggs in 18 egg masses were field collected and returned to the laboratory, where emerging parasitoids were identified to species. In addition, 2,512 laboratory-reared E. servus eggs and 230 P. maculiventris eggs were placed as sentinels into crop fields and collected after 7 d, and parasitoid or stink bug emergence was recorded. Four species of hymenopteran parasitoids in the family Scelionidae were recovered from stink bug eggs: Telenomus podisi Ashmead, Trissolcus basalis Wollaston, Trissolcus edessae Fouts, and Trissolcus euschisti Ashmead. In addition, one parasitoid in the family Mymaridae (Hymenoptera) was recovered. Parasitism rates were highest in E. servus with 89.7 and 49.2% of egg masses and individual eggs parasitized, respectively. The predominant parasitoid species was T. podisi.

Attraction of the invasive halyomorpha halys (Hemiptera: Pentatomidae) to traps baited with semiochemical stimuli across the United States

Abstract Life table studies of European corn borer, Ostrinia nubilalis (Hübner), populations with and without inoculative releases of Trichogramma ostriniae (Peng & Chen) were conducted in sweet corn and field corn. Inoculative releases of T. ostriniae (at 72,000 females per hectare) provided relatively high parasitism of European corn borer eggs (≈37%) throughout the season. The increase in egg parasitism was not offset by compensatory changes in other mortality rates such as egg predation, eggs not hatching, and death of early instars after egg hatch. Early instar disappearance was a key mortality factor accounting for >70% of total mortality from egg deposition to established larvae. Egg parasitism by T. ostriniae was also a key mortality factor. Releases of T. ostriniae increased total egg and larval mortality of O. nubilalis from 61 to 92% in sweet corn and from 80 to 93% in field corn.

Control of corn flea beetle and Stewart's wilt in sweet corn with imidacloprid and thiamethoxam seed treatments.

ABSTRACT A recent identification of the two-component aggregation pheromone of the invasive stink bug species, Halyomorpha halys (Stål), in association with a synergist, has greatly improved the ability to accurately monitor the seasonal abundance and distribution of this destructive pest. We evaluated the attraction of H. halys to black pyramid traps baited with lures containing the pheromone alone, the synergist methyl (2E,4E,6Z)-decatrienoate (MDT) alone, and the two lures in combination. Traps were deployed around areas of agricultural production including fruit orchards, vegetables, ornamentals, or row crops in Delaware, Maryland, North Carolina, New Jersey, New York, Ohio, Oregon, Pennsylvania, Virginia, and West Virginia from mid-April to mid-October, 2012 and 2013. We confirmed that H. halys adults and nymphs are attracted to the aggregation pheromone season long, but that attraction is significantly increased with the addition of the synergist MDT. H. halys adults were detected in April with peak captures of overwintering adults in mid- to late May. The largest adult captures were late in the summer, typically in early September. Nymphal captures began in late May and continued season long. Total captures declined rapidly in autumn and ceased by mid-October. Captures were greatest at locations in the Eastern Inland region, followed by those in the Eastern Coastal Plain and Pacific Northwest. Importantly, regardless of location in the United States, all mobile life stages of H. halys consistently responded to the combination of H. halys aggregation pheromone and the synergist throughout the entire season, suggesting that these stimuli will be useful tools to monitor for H. halys in managed systems.

Cold tolerance of Halyomorpha halys (Hemiptera: Pentatomidae) across geographic and temporal scales

Abstract Two field-plot experiments were conducted in western and central New York to evaluate imidacloprid and thiamethoxam seed treatments for control of corn flea beetle, Chaetocnema pulicaria Melsheimer, and Stewarts bacterial wilt in three varieties of sweet corn. Seed treatments significantly reduced flea beetle feeding injury to leaves in all varieties and reduced disease incidence 37–83% in the susceptible variety ‘Sprint’. Seed treatments did not control Stewarts wilt as effectively as genetic resistance. Disease incidence in the resistant varieties ‘Dynamo’ and ‘Bonus’ was relatively low (⩽5%) with or without a seed treatment. Additional on-farm evaluations conducted in western New York confirmed the results obtained from our field plots with incidence of Stewarts wilt ≈88% lower in imidacloprid-treated fields compared with non-treated fields. Laboratory germination tests indicated that seed treatments with imidacloprid may have some phytotoxic effects, depending on sweet corn variety and vigor of the seed lot. A general recommendation is that only high quality seed lots should be treated with imidacloprid and that carry-over seed should not be used.

Does Feeding by Halyomorpha halys (Hemiptera: Pentatomidae) Reduce Soybean Seed Quality and Yield?

Abstract The brown marmorated stink bug, Halyomorpha halys (Stål), is native to eastern Asia and is presently invading North America. Little is known about the exposure to and effects of winter temperatures in newly invaded regions on H. halys. The overwintering habitats that this species utilizes vary greatly in their thermal buffering capacity. They naturally overwinter in aggregations beneath loose bark on trees and in cliff outcroppings, but will also commonly aggregate in buildings. Effects of cold temperatures such as mortality and freezing have yet to be quantified in the invading population. We report that H. halys is chill intolerant (i.e., dies before reaching its freezing point), and that the degree of cold tolerance of populations in North America differs by season, sex, and acclimation location. The mean winter supercooling point (± SEM) of individuals acclimated in Minnesota was –17.06°C ± 0.13 and in Virginia was –13.90°C ± 0.09. By using laboratory assays of lower lethal temperatures and ambient air temperature records, we accurately forecasted mortality for field experiments in Minnesota and Virginia. Temperature refugia provided by human-built structures are likely crucial for overwintering survival during atypically cold winters and possibly contribute to the northern geographic range expansion of this economically damaging insect in the temperate climates of North America.

Fifty Years of Cereal Leaf Beetle in the U.S.: An Update on Its Biology, Management, and Current Research

ABSTRACT 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.

Integrating Chemical and Biological Control of European Corn Borer in Bell Pepper

Cereal leaf beetle, Oulema melanopus L., is an introduced insect pest of small grains first recorded in the United States in the early 1960s. Since its introduction from Europe or Asia into Michigan, cereal leaf beetle has rapidly spread and can now be found in most states. Cereal leaf beetle feeds on numerous species of grasses and is considered a major pest of oats, barley, and wheat. Although several studies have investigated cereal leaf beetle biology and population dynamics, numerous gaps remain in understanding the mechanisms that influence its spread and distribution, which makes predicting pest outbreaks difficult. Because of the difficulty in predicting when and where pest outbreaks will occur many growers in the southeast apply insecticides on a calendar basis rather than using a threshold-based integrated pest management approach. Our challenge is to develop new information and procedures that will encourage growers to reevaluate the way they are approaching spring-time insect control in wheat, and consider adoption of the integrated pest management approach. This article is a review of cereal leaf beetle biology, past and present management practices, and current research being conducted.

Indigenous arthropod natural enemies of the invasive brown marmorated stink bug in North America and Europe

ABSTRACT Using multiple locations and a series of field trials over 2 yr, we evaluated an integrated pest management program for Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) management in peppers involving biorational chemistries, inundative releases of Trichogramma ostriniae (Pang & Chen), and conservation of generalist predators. In small plot trials, three biorational insecticides (spinosad, indoxacarb, and methoxyfenozide) provided comparable control of O. nubilalis as two broad-spectrum conventional insecticides (acephate and lambda-cyhalothrin). However, lambda-cyhalothrin at most locations, and indoxacarb at one location, resulted in outbreaks of green peach aphids. We also observed significant effects on the generalist predator community: beneficial communities in methoxyfenozide-treated plots were most similar to untreated controls, and acephate-treated plots were the least similar. Management systems comparing untreated controls, inundative release of T. ostriniae with methoxyfenozide applied when lepidopterans exceeded thresholds, or weekly applications of acephate or lambda-cyhalothrin, showed no effects on marketable fruit or percentage of fruit damaged, but the conventional insecticide approach caused aphid flares. Inun-dative releases of T. ostriniae and biorational chemistries provide a more environmentally sound approach to managing O. nubilalis in peppers, due, in part, to conservation of generalist predators.