Transgenic crops containing the bacterium (Bt) genes reduce pests and insecticide usage, promote biocontrol services, and economically benefit growers. Area-wide Bt adoption suppresses pests regionally, with declines expanding beyond the planted Bt crops into other non-Bt crop fields. However, the offsite benefits to growers of other crops from such regional suppression remain uncertain. With data spanning 1976-2016, we demonstrate that vegetable growers benefit via decreased crop damage and insecticide applications in relation to pest suppression in the Mid-Atlantic United States. We provide evidence for the regional suppression of (Hübner), European corn borer, and (Boddie), corn earworm, populations in association with widespread Bt maize adoption (1996-2016) and decreased economic levels for injury in vegetable crops [peppers ( L.), green beans ( L.), and sweet corn ( L., convar. )] compared with the pre-Bt period (1976-1995). Moth populations of both species significantly declined in association with widespread Bt maize (field corn) adoption, even as increased temperatures buffered the population reduction. We show marked decreases in the number of recommended insecticidal applications, insecticides applied, and damage in vegetable crops in association with widespread Bt maize adoption. These offsite benefits to vegetable growers in the agricultural landscape have not been previously documented, and the positive impacts identified here expand on the reported ecological effects of Bt adoption. Our results also underscore the need to account for offsite economic benefits of pest suppression, in addition to the direct economic benefits of Bt crops.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an Asian species that now dominates the stink bug complex in many cultivated crops throughout the mid-Atlantic United States. Sweet corn (Zea mays L.) is a preferred host of H. halys, and the bug can cause kernel injury on developing ears. Currently, there is limited information available on which plant growth stages are most sensitive to H. halys feeding or density of bugs required to cause yield and quality reductions on processing and fresh market sweet corn ears. In 2011 and 2012, sweet corn ears were infested at three different corn growth stages: silking (R1), blister (R2), and milk (R3) at densities of zero, one, three, and five H. halys adults per ear for 7 d. At harvest, four yield measurements were assessed and ears were inspected for quality reductions. The greatest yield loss from H. halys occurred when infestations were initiated during early stages of ear development, and the greatest quality reductions (damaged kernels) occurred during later stages of ear development. A density of one H. halys per ear resulted in levels of kernel damage great enough to cause significant quality reductions. This study highlights the ability of H. halys to cause substantial economic losses in both fresh market and processing sweet corn in a relatively short period of time at low population densities. Therefore, infestations by this insect in sweet corn must be considered when making pest management decisions in regions where it has become established.

Slugs are cryptic terrestrial pests that target a wide range of crops and are especially damaging to seedlings. Management of these invertebrates mostly relies on synthetic chemistry. These molecules can be efficient against slugs and snails but can be toxic to other organisms (e.g., dogs) and harmful to the environment (e.g., leaching into surface and groundwater). The usage of pathogenic nematodes has been effective in several crops and European countries. A survey was conducted to investigate the presence of natural populations of malacopathogenic nematodes in soybean in the mid-Atlantic region. Slugs were sampled in nine fields across Delaware at various distances from the field edges (0 m, 5 m, 10 m, 15 m). Soil cover and soil type were also recorded. Invertebrates were brought back to the laboratory. Slugs were monitored for four weeks, and mortality was classified into one of three categories: (1) death with the presence of nematodes; (2) death with the presence of fungi; (3) death without the presence of nematodes or fungi. Nematodes associated with slugs were identified based on 18S rRNA sequencing. The distance from the field edge did not impact the number of trapped slugs and the incidence of slug death associated with the presence of nematodes. Overall, nematodes were collected from ca. 20% of the slug cadavers, and most have previously been associated with slugs (ca. 35% of deaths associated with fungi and ca. 45% not associated with nematodes or fungi). The number of captured slugs and slug death associated with the presence of nematodes were positively correlated with ground cover. Soil type impacted both the number of captured slugs and the presence of pathogenic nematodes. This survey provides a first insight into the natural populations of mollusk-associated nematodes in the mid-Atlantic region. This knowledge may contribute to implementing cultural practices favoring these natural enemies of slug pests.