Influência do pH da água e do tempo entre preparo da calda e pulverização de thuricide wp no controle de Chrysodeixis includens em soja

Abstract

Nowadays, Chrysodeixis includens, popularly known soybean looper, is one of the most important pest lepidopteran species in soybean. Currently, chemical control and the use of Bt crops are the most used control tactics for the management of C. includens. However, recently reports of false-measure resistance have been reported in the country. Bt bioinsecticides appear as an important control tool, however much information about the quality of the water used for spraying is necessary, as well as how much the solution can be prepared without losing efficiency. The aim of the present work was to evaluate the efficiency of Bt bioinsecticides in mixtures with different pH values and preparation time on C. includens. The bioassay was performed in a factorial scheme with additional treatment [(3x5) +1] and 42 repetitions (Larvaes). Three spray water pH values (2.00, 6.00 and 10.00) were analyzed in combination with 5 application times After Preparation spray time of the PST (0, 3, 6, 12, 24 hours) and a control (water). The insecticide subjected to the spray preparation conditions was Thuricide WP, at a dose of 500 g/ha. The experiment was carried out in a factorial scheme with additional treatment [(3x5) +1] and 42 repetitions (Larvaes). Three spraying water pH values (2.00, 6.00 and 10.00) were analyzed in combination with 5 application times After Preparation of the PST (0, 3, 6, 12, 24 hours) and a control (water). The insecticide subjected to the spray preparation conditions was Thuricide WP, at a dose of 500 g/ha applied to soybean plants, after 60 minutes leaf discs were collected and supplied to 2nd instar caterpillars. Mortality was assessed for 5 days. The present work showed that the Thuricide product showed that in the pH values of the water and time after the syrup preparation, there was no significant difference between the treatments when evaluated 5 days after application.