What this means
Scientists tested three caterpillar pests on two types of Bt soybean and regular soybean. The results may help plan ways to slow pest resistance.
Plain-English summary written by an AI model from the abstract. The original is below.
- Who it was tested in
- Three caterpillar species fed soybean leaves, flowers, and pods in a lab
- Kind of research
- A study
The science
- Original title
- Survival and development of Spodoptera species (Lepidoptera: Noctuidae) on Bt and non-Bt soybeans and implications for resistance management strategies in Brazil.
- Authors
- Szczecinski T, Ferreira JP, Martins LN et al.
- Journal
- Journal of economic entomology
- Published
- Oct 14, 2026
- Study type
- Study
- PMID
- 42875026 ↗
Abstract
Spodoptera species are among the major defoliating pests of soybean crops in Brazil, and their low natural susceptibility to certain Bt insecticidal proteins poses a challenge for insect resistance management programs. To inform resistance management strategies, this study evaluated the biological parameters and life history and fertility profiles of Spodoptera frugiperda, Spodoptera eridania, and Spodoptera cosmioides fed on leaves, flowers, and pods from non-Bt soybeans and Bt soybeans expressing Cry1Ac (Intacta RR2 PRO) and Cry1Ac + Cry1A.105 + Cry2Ab2 (Intacta2 Xtend). Second-instar larvae of the 3 species exhibited 100% mortality when fed Intacta2 Xtend leaves. Regardless of the treatment evaluated, none of the species completed development from egg to adult when fed flowers or pods. In contrast, caterpillars fed Intacta RR2 PRO leaves completed their development from egg to adult, with survival rates of 62.9%, 56.4%, and 29.7% for S. frugiperda, S. eridania, and S. cosmioides, respectively. However, surviving individuals fed Intacta RR2 PRO exhibited lower larval and pupal mass, reduced fecundity, and a decrease of approximately 26% in the net reproduction rate (R0), compared to those fed non-Bt soybeans. Overall, Intacta2 Xtend soybeans exhibited greater insecticidal activity against the 3 Spodoptera species, while soybeans expressing only Cry1Ac predominantly produced sublethal effects. These results expand our understanding of the biological responses of S. frugiperda, S. eridania, and S. cosmioides to the Bt soybean biotechnologies available in Brazil and provide insights for insect resistance management strategies aimed at preserving the longevity of these technologies.
Szczecinski T, Ferreira JP, Martins LN et al. Survival and development of Spodoptera species (Lepidoptera: Noctuidae) on Bt and non-Bt soybeans and implications for resistance management strategies in Brazil. Journal of economic entomology. 2026. doi:10.1093/jee/toag308. PMID: 42875026. https://pubmed.ncbi.nlm.nih.gov/42875026/