ABSTRACT
With the objective to verify the effect of Thiamethoxam, Pymetrozine and Diafentiuron on Aphis gossypii and ladybeetles in cotton plant ‘Deltaopal’ this study was conducted, in Ribeirão Preto, SP, Brazil. The following treatments were tested (g i.a/ha): thiamethoxam 250 WG (500); Pymetrozine 500 PM (100); Diafentiuron 500 SC (250); Thiamethoxam 250 WG more Pymetrozine 500 PM (42,5 + 75); Carbosulfan (160); Imidacloprid 200 SC (50) and untreated. It was examined 25 whole plants per plot, counting the number of aphids present in this. The selectivity study consisted of application on the ladybeetles and plant with aphids; application in plants with aphids and placement of the ladybeetles in the cages (15 x 30 cm, working with samples of five adult insects). Four plants per plot were covered with tulles with five ladybeetles inside, before the application as well as after the field application. The survival was evaluated up to 5 days after application or exposure to the treatment. In the field, good control of the aphids was verified, not differing the treatments, but of the check, while for lady beetles, all of the treatments didn’t differ among them in the first day after the application, so much under direct application, as indirect exposure. By the subsequent days higher mortality was observed, by the same test made in laboratory, when the thiamethoxam, pymetrozine and diafentiuron showed smaller effect on the predator, than carbosulfan.
KEY WORDS Lady beetles; cotton; selectivity; Thiamethoxam; Pymetrozine; Diafentiuron