Toxicidade, efeito residual e repelência de acaricidas sintéticos e produtos naturais sobre Tetranychus urticae koch e Phytoseiulus macropilis (Banks), em algodoeiro

Abstract

This work studied the lethal and sublethal effects, repellency, toxicity and residual effects of natural and synthetic acaricides on the two spotted mite, Tetranychus urticae Kock (Acari: Tetranychidae), and its predator, Phytoseiulus macropilis (Acari: Phytoseiidae). The synthetic acaricides fenpropathrin, chlorfenapyr, diafenthiuron, abamectin and spiromesifen and the botanicals oils of neem, Azadirachta indica A. Juss. (Meliaceae), Azadirachtin 1% and Azadirachtin A/B, Jatropha curcas L. (Euphobiacea) and Ricinus communis L. (Euphorbiacea) were tested. Based on LC50s e LC90s, spiromesifen was the most toxic to female mites and J. curcas to T. urticae eggs. To P. macropilis, the acaricides that caused more adverse effects were spiromesifen, J. curcas and Azadirachtin 1%. Oil of J. curcas used at sublethal concentrations was the only able to extinguish the population of T. urticae. Spiromesifen, R. communis and Azadirachtin A/B affected negatively the growth population of the two spotted spider mite. Population of P. macropilis exposed to spiromesifen, oil of J. curcas, and Azadirachtin 1% trended to extinction. However, when exposed to oil of R. communis and Azadiracthin A/B continued to grow. All acaricides tested, except oil of R. communis, were repellent to T. urticae females and affected oviposition of T. urticae. The treatment with oil of R. communis, J. curcas, and Azadiracthin 1% were repellent to the predatory female mites and affected its oviposition. The residual effect of fenpropathrin, chlorfenapyr, diafenthiuron, and abamectin caused mortality to T. urticae female over 90% up to the fourth evaluation. Fenpropathrin, diafenthiuron, abamectin, and spiromesifen caused reduction on female fecundity. The natural products tested were efficacious to two spotted spider mite adults only during the first evaluation. All tested acaricides exhibited efficacious control of T. urticae, but among the tested products the Azadiracthin A/B produced promising results to mite control in cotton ecosystem and was less harmful to the predatory mite.