Regional pest suppression associated with widespread Bt maize adoption benefits vegetable growers

Abstract

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.

Field‐evolved resistance by western corn rootworm to Cry34/35Ab1 and other Bacillus thuringiensis traits in transgenic maize

“…The vast majority of the area planted to Bt crops consists of cotton and maize, with Bt crops targeting both lepidopteran (caterpillars) and coleopteran (beetles) insect pests . Some of the primary benefits of planting Bt crops include a reduction in the use of conventional insecticides, reduced harm to non‐target organisms, and regional suppression of key insect pests, an effect that can benefit farmers whether or not they plant Bt crops due to lower overall yield losses from insect pests . However, with the rapid adoption of Bt crops there also have been several cases of pests evolving Bt resistance, which in turn can diminish these benefits …”

“…3 Some of the primary benefits of planting Bt crops include a reduction in the use of conventional insecticides, reduced harm to non-target organisms, and regional suppression of key insect pests, an effect that can benefit farmers whether or not they plant Bt crops due to lower overall yield losses from insect pests. [4][5][6][7][8][9] However, with the rapid adoption of Bt crops there also have been several cases of pests evolving Bt resistance, which in turn can diminish these benefits. 10 In order to delay the evolution of Bt resistance, farmers in the United States and elsewhere use the refuge strategy, which consists of growing non-Bt host plants in conjunction with a Bt crop.…”

Impact of climate change on Ostrinia nubilalis (Lepidoptera: Crambidae) phenology and its implications on pest management

“…In New York, both ECB races (univoltine and bivoltine) overlap, but with a greater proportion of bivoltine ECB in the southern part (O'Rourke et al, ). Pest populations vary from year to year, but it seems that since the widespread use of Bt ( Bacillus thuringiensis ) in field corn, populations of ECB have dropped significantly in the United States (Hutchison et al, ; Dively et al, ). Nevertheless, the ECB moth is still the main enemy of sweet corn in those two regions and also attacks alternative crops such as pepper and snap bean.…”

Weather and regional crop composition variation drive spatial synchrony of lepidopteran agricultural pests

“…Major changes in agricultural technology occurred concurrently, including the introduction of Bt corn and glyphosate‐resistant soybeans in the mid‐1990s (Padgette et al ., ; Fernandez‐Cornejo and Wechsler ). Consistent with previous reports for the region, corn earworm and European corn borer showed population declines attributable to Bt corn (Dively et al ., ). Not previously reported, populations of forage looper also declined.…”

“…Specifically, natural‐log‐transformed pest abundance was modelled as a function of one fixed effect, year, and one random effect of trapping region on the intercept. We expected non‐linear abundance trends in at least some of our focal species given prior work demonstrating population declines following the introduction of transgenic, insect‐resistant ‘ Bacillus thuringiensis ’ crops in 1996 (Dively et al ., ). We restricted the maximum number of degrees of freedom of the spline to k = 3 so that the GAMM captured only general long‐term trends, not oscillatory patterns that were the focus of our synchrony analyses.…”