Toxicity of agrochemicals to the citrus leprosis mite Brevipalpus phoenicis (Geijskes) and predator mite Neoseiulus Californicus (McGregor) (Acari: Tenuipalpidae, Phytoseiidae)

摘要

The objective of this study was to evaluate various pesticides used in citrus crops in regard to their toxicity to Brevipalpus phoenicis and Neoseiulus californicus, a potential predator of phytophagous mites in the crop. Bioassays were conducted using orange-tree leaf discs for N. californicus and fruits for B. phoenicis. A total of 35 adult females of the predator mite were used, along with 50 adult females of the phytophagous mites. Tests were carried out with 13 chemicals at concentrations recommended for the control of leprosis mites. The applications were made using a Potter tower, with 4 replications for each treatment. Assessments of the number of live and dead mites were observed 72 hours after application. Bioassays with spirodiclofen and etoxazole were performed on eggs of mites. Chlorfenapyr and pyridaben proved harmful to N. californicus, causing mortalities of 88 and 99% respectively. Abamectin caused mortality of 62%, considered high when compared to dinocap (2%), propargite (4.2%), sulfur (5%), fenpropathrin (12.4%) and acrinathrin (22%). Cyflumetofen oxide, fenbutatin and deltamethrin were harmless to N. californicus. Spirodiclofen did not cause egg mortality or larvae mortality in N. californicus, however etoxazole caused 100% mortality in larvae of the predator on contact with the residue of the product. For B. phoenicis, abamectin, chlorfenapyr, dinocap, cyflumetofen, fenbutatin oxide, pyridaben and propargite caused 100% mortality. Fenpropathrin (95%), acrinathrin (87%) and sulfur (76%) were less effective. Deltamethrin was not effective in controlling leprosis mites. Etoxazole and spirodiclofen caused 100% egg mortality for B. phoenicis.