Abstract

AREVALO, Helber; ZENNER DE POLANIA, Ingeborg  and  ROMERO, Laura. EFFECTS OF MERIDIC DIETS ON THE Bacillus thuringiensis CRYSTALINOUS PROTEINS (Cry) TOXICITY UPON THREE COTTON PESTS (LEPIDOPTERA: NOCTUIDAE). rev.udcaactual.divulg.cient. [online]. 2011, vol.14, n.1, pp.39-48. ISSN 0123-4226.

Since the introduction of genetically-modified (transgenic) crops around the world, an effort to monitor the susceptibility to Cry toxins on targeted insects has been implemented. However, these results are hardly comparable from region to region, not only due to the use in strains from different parts, but also due to methodological differences. Among these discrepancies is the use of meridic diets containing different ingredients. The goal of this study was to evaluate the effect of three meridic diets on the toxicity of crystal proteins from the bacterium B. thuringiensis on three cotton pests from El Espinal and Tolima. In all the tests, the lowest susceptibility was obtained with the ICRISAT diet, which in turn, it is superior for rearing these pests under our environmental conditions. The results also suggest that there is an increase or dilution of resistance in Heliothis virescens populations due to the fact that these insects were collected from Desmodium sp. Spodoptera frugiperda’s susceptibility was not affected, nor acquired resistance, while Helicoverpa zea had a slightly increase in susceptibility. These results suggest that Btsusceptibility should continue using the same methodology to decrease variability as well as tests to be conducted on populations from different areas and host plants.

Keywords : Meridic diets; Cry toxins; Spodoptera frugiperda; Helicoverpa zea; Heliothis virescens.

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