Comparative susceptibility of Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae) and Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) to insecticides

Nayara Buss,Samanta Souza Restelatto,Mari Inês Carissimi Boff,Cláudio Roberto Franco,Oderlei Bernardi,Rafael Ermenegildo Contini,Adeney De Freitas Bueno

doi:10.1590/0103-8478cr20210047

Abstract

ABSTRACT: Chrysodeixis includens (Walker) and Anticarsia gemmatalis Hübner are important soybean defoliators. The chemical control of A. gemmatalis has been easier and more effective than that of C. includens. It is hypothesized that C. includens is natural tolerant to insecticides. This study quantified and compare the susceptibility of C. includens and A. gemmatalis to the insecticides flubendiamide, methomyl, and spinetoram. A susceptible population of each species, maintained under laboratory conditions without insecticides selection pressure for more than 17 generations, was used. Ingestion bioassays using five to eight concentrations of each insecticide applied on the artificial diet surface were used to estimate the LC50 and LC99 (LC = Lethal Concentration). The tolerance ratio (TR) was calculated by dividing the LC50 or LC99 of the most tolerant species by the respective value of the most susceptible species. Chrysodeixis includens was more tolerant to all insecticides tested than A. gemmatalis, with TR50 values of 45.9-, 10.0- and 2.6-fold for methomyl, flubendiamide, and spinetoram. These findings indicated that the risk of evolution of resistance may be higher for C. includens than A. gemmatalis due to differential survival when exposed to the same dose of insecticide applied in soybean fields. Therefore, to improve the control of both species, integrated pest management (IPM) and insect resistance management (IRM) strategies should be considered to avoid control failures in field conditions.

Highlights

Insect pests are an important biotic factor that reduces soybean [Glycine max L. (Merr.)] yield (OLIVEIRA et al, 2014; SILVA et al, 2020)
The difference in susceptibility to insecticides between lepidopteran species is another factor that may have contributed to the high incidence of C. includens in soybean (MORAES et al, 1991)
Based on this, wequantified and compared the susceptibility of A. gemmatalis and C. includens to the insecticides flubendiamide, methomyl, and spinetoram

Summary

Introduction

Insect pests are an important biotic factor that reduces soybean [Glycine max L. (Merr.)] yield (OLIVEIRA et al, 2014; SILVA et al, 2020). The difference in susceptibility to insecticides between lepidopteran species is another factor that may have contributed to the high incidence of C. includens in soybean (MORAES et al, 1991). Chrysodeixis includens has naturally been more tolerant to insecticides than other species such as A. gemmatalis (ROSE et al, 1988) and Helicoverpa armigera (HÜBNER, 1808) (Lepidoptera: Noctuidae) (SCHNEIDER & SOSA-GÓMEZ, 2016).

Results

Conclusion