Solução hidroalcoólica e extrato de carqueja doce para o controle de gorgulho em grãos de milho

Abstract

This study evaluated the preference index and the insecticide effect of different concentrations of water-alcohol solution and carqueja extract for weevil control in corn kernels. For the experiment were used unsexed insects, aged between 15 and 30 days. The hydroalcoholic solution consisted of alcohol + water in the following concentrations: 90% etanol + 10% water; 70% etanol + 30% water; 50% etanol + 50% water; 30% etanol + 70% water; 10% etanol + 90% water. The carqueja extract consisted of alcohol + water + plant, in the aforementioned concentrations, however were added 100g of dry plant. The experiment was conducted as a completely randomized design, with four replications, in a factorial way 2 x 5 x 5 + 1 (product, x concentration x time + 1 witness), insecticide activity and 2 x 5 x 5 + 1 (product, x concentration x time + 1 witness) for repellent and, where was used 1ml of product for each treatment, using a manual spray, in 50g of corn kernels sterilized. Evaluations were made after 2, 6, 12, 24 and 48h and after the 24 and 48h, for insecticide and repellent activity, respectively. The results demonstrate that the carqueja extract showed attractive effect for maize weevil, except for the concentration of 10%, which obtained neutral effect, the hydroalcohol solution had a neutral effect on the repellency on the grain mite and both products, when applied in concentrations exceeding 30% resulted in high mortality rates.