Effect of varieties of cotton GM on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) larvae

摘要

Spodoptera frugiperda, is a polyphagous pest with economic importance in tropical and subtropical countries. In Colombia, S. frugiperda is a secondary pest in cotton. This cultivar has gained importance due to the adoption of genetically modified crops (GM). The objective of this study was to determine the sub-lethal effects of GM cotton varieties on S. frugiperda larvae. In order to do so, NuOPAL RR (Cry1Ac), DP141 B2RF (Cry1Ac+Cry2Ab) and DeltaOPAL RR (No-Bt) varieties were tested under laboratory controlled conditions (27°C, 65 ±10% RH and 12 h photoperiod). The parameters to be evaluated were: (a) weight of larvae, (b) weight of feces, (c) weight of provided food and, (d) weight of non-consumed food. Digestibility and consumption indexes were calculated: Relative Consumption Rate (RCR), Relative Growth Rate (RGR), Efficiency of the Conversion of Ingested Food (ECI) and the Approximate Digestibility (AD). The nutritional indexes show antifeedant activity of DP141 B2RF, (Cry1Ac+Cry2Ab), affecting in a negative way the growth rate and the conversion of larvae food. The weight gained by larvae fed with DP141 B2RF (Cry1Ac+Cry2Ab) was 58.6% less than the control. These results suggest an unfavorable effect of DP141 B2RF (Cry1Ac+Cry2Ab) in the larval development of S. frugiperda. The antibiotic effects were confirmed observing minor development and a negative effect in the survival of larvae fed on GM cotton.