Atividade de inseticidas químicos no controle do pulgão Aphis gossypii glover, 1877 (Hemiptera: Aphididae) na cultura do algodoeiro

Abstract

Cotton (Gossypium hirsutum L.) is one of the main crops in Brazil, being a product of extreme socioeconomic importance. In addition to being the largest source of natural fibers, it guarantees the country a privileged place on the international scene, as one of the five largest producers in the world. Given its great value, it is important to be aware of the possibility of pests and diseases that can significantly reduce production, such as the cotton aphid, Aphis gossypii, which causes direct (sucking sap and injecting toxins). and indirect (smog, viruses) to the crop. In this sense, the objective of this work was to evaluate the practicality and agronomic efficiency of the insecticides MOSPILAN WG (acetamipride), IMIDAGOLD 700 WG (imidacloprid), ACTARA 250 WG (thiamethoxam), SPERTO (acetamipride + bifenthrin), MARSHAL™ STAR (carbosulfan), TALISMAN® (bifenthrin + carbosulfan), Lorsban® 480 BR (chlorpyrifos), BENEVIA® (cyantraniliprole), in the control of the cotton aphid, in the cotton crop, under field conditions. The experiment was carried out at the Experimental Farm of the Federal University of Uberlândia Campus Glória in the municipality of Uberlândia-MG. An experimental design was used in randomized blocks with nine treatments and four replications, one control without application and eight insecticides. Each plot consisted of six (6) rows, spaced 0.5m apart and 5m long, totaling 15m2. The evaluations were carried out at 0 (previous count), 2, 5, 10, 18 days after the first application and at 7, 11, 16 and 22 days after the second application, by counting the number of aphids in five plants per plot, marked with a piece of white string. The application was carried out via the leaves, using a Jacto PJB-8C knapsack sprayer, equipped with a boom containing 2 empty cone-type spray nozzles, with a working pressure of 60 Psi and a spray volume of 200 L/ha. After analyzing the data, under the conditions of the experiment, it was found that acetamiprid provided better control of the cotton aphid, with a higher control index, with 71% efficiency, having a shock effect (ability to eliminate or incapacitate the insects quickly, after the moment they come into contact with the insect, that is, they act quickly and immediately), and it has a greater residual, remaining for a certain period after its application compared to other insecticides.