The role of genetically engineered soybean and Amaranthus weeds on biological and reproductive parameters of Spodoptera cosmioides (Lepidoptera: Noctuidae)

Abstract

BACKGROUND: In soybean fields containing insecticide-and herbicide-resistant genetically engineered varieties, some weed species have increasingly become difficult to manage and may favor the population growth of secondary pests like Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae). To test this hypothesis, we measured life-history traits, population growth parameters and adult nutrient content of S. cosmioides reared on foliage from four Amaranthus species, from Cry1Ac Bt and non-Bt soybean varieties, and on meridic artificial diet. RESULTS: Larvae reared on A. palmeri and A. spinosus had a shorter development time (5-7 days) than larvae raised on the soybean varieties and A. hybridus. Armyworm survival probability was zero on A. viridis and highest (80% and 71%) on soybeans and A. palmeri. The latter and the artificial diet produced the heaviest larvae and pupae, in contrast to the non-Bt soybean variety. Body nutrient content diverged mostly for adults reared on artificial diet compared with those raised on the soybean varieties. The intrinsic rate of population increase (overall fitness) was 27.88% higher for the armyworms on A. palmeri, Cry1Ac Bt soybean and artificial diet compared with those on non-Bt soybean, A. spinosus and A. hybridus.CONCLUSIONS: Cry1Ac soybean fields infested by some Amaranthus weeds, especially A. palmeri, are conducive to the population growth of S. cosmioides. Integrated pest management programs may be needed to properly manage S. cosmioides in soybean fields, with surveillance for population peaks and judicious control measures when needed.

Biology of Spodoptera Eridania (Cramer, 1792) (Lepidoptera: Noctuidae) at Different Temperatures and Diet Sources

“…The interference of the biotic factor may be related to insects feeding on plants with low nutritional quality, which can affect their biological, physiological, and behavioral characteristics, through the reduction of size, weight, survival, the intensity of consumption by larvae, longevity, and potential reproductive, etc. (Cabezas et al 2013;Gomes et al 2017;Schowalter 2016b;Silva et al 2017;Silva et al 2019;Zamora Belli et al 2020;Páez Jerez et al 2022;Parra et al 2023).…”

The need for assessment of risks arising from interactions between NGT organisms from an EU perspective

“…Interactions between the transgenic traits were also described in another case in Brazil [103]: according to their findings, the spread of Amaranthus weeds (Amaranthus palmeri) in soybean fields is facilitated by the cultivation of the transgenic herbicide-resistant plants. It was found that if black armyworm larvae (Spodoptera cosmioides) fed on A. palmeri, this had positive effects on its biological and reproductive parameters.…”