Efeito de indutores da resistência e cultivares de algodão no comportamento de Aphis gossypii

Abstract

Aimed to evaluate the effect of silicon, acibenzolar-S-methyl (ASM) and cultivars of cotton plant on the behavior of A. gossypii. Were conducted non-preference trials with apterous aphid and with winged aphid, both with nine treatments arranged in a factorial scheme 3 (inductors: Silicon ASM and Control) x 3 (cultivars BRS Verde, BRS Rubi and Safira), with thirteen replications. The treatments were distributed in a factorial scheme 3 (cv. BRS Verde, BRS Safira and BRS Rubi) x 3 (silicon, ASM and control) with thirteen replicates. Silicic acid at the dosage equivalent to 3 t ha-1 and 0.2% ASM were tested. For the test with apterous aphid, after 14 days from the application of the inducers, leaf sections of each treatment were placed into Petri dishes forming an arena where 24 adults aphid were released. The number of adults and nymphs of the aphid was evaluated after 24; 48 and 72 hours after release. For the second test, after 14 days from the application of the inducers, winged aphids were released randomly on the plants grown in an acclimatized chamber. After 24; 48 and 72 hours from the release, the number of winged adults and of nymphs present on the plants was evaluated. From the results, the both cv. Verde and Rubi were less infested in relation to Safira and the application of silicon did not affect the preference of A. gossypii. However the product ASM proved viable and could contribute to the reduction of the colonization of the plants by aphids.