Phytophagous mites on genetically modified maize with Bacillus thuringiensis genes

Abstract

The study of non-target organisms such as mites, can provide information about the possible effects of transgenic maize cultivars on the arthropod community. This study aimed to evaluate the abundance of phytophagous mites in the area of Bt maize and evaluate the instantaneous population growth rate, and food preference of phytophagous mites on Bt maize. We registered the species occurrence and the number of adult mite individuals on four maize cultivars, one non-Bt 30F35, and three containing the proteins Cry1Ab (30F35 Yg), Cry1F (30F35 Hx) and Vip3a (Impacto Viptera). Cry proteins disrupt the midgut epithelium of insect pests. The food preference and instantaneous population growth rate (ri) were evaluated using the two-spotted spider mite Tetranychus urticae as model. The species Catarhinus tricholaenae and Aceria zeala were recorded. The Bt maize cultivars did not significantly affect the average number of C. tricholaenae and A. zeala mites compared to conventional cultivar. The population growth rates of T. urticae were similar for the different maize cultivars. T. urticae showed no preference between the leaf of Bt or conventional cultivars. Bt maize did not affect the abundance of species in phytophagous mite.

Direct defense elicited by Tetranychus urticae koch (Acari: Tetranychidae) in Bt maize plants

“…Therefore, the plant defense conferred by inserting the Bt gene did not negatively interfere in the pre-existing direct defense induction capacity of maize plants. Ferreira et al (2017) reported that T. urticae showed no preference between the Bt or conventional maize leaves, and did not affect the abundance of species in phytophagous mite. Similarly to the results non-Bt maize plants results, the pre-infestation of Bt maize plants by T. urticae did not resulted in significant reductions of the mite survival and reproductive abilities.…”

Resistência de três genótipos de milho ao ataque de Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) em laboratório

“…Nesse contexto, essa menor ri pode ser atribuída a características do milho pipoca (Paes 2008) que pode ser menos apropriada para o desenvolvimento de S. zeamais. O fato do milho Bt ter apresentado a maior ri pode ser atribuído as proteínas inseticidas sintetizadas não serem efetivas contra organismos não alvo (Ferreira et al, 2017), como S. zeamais.…”