Comparação da sensibilidade do ácaro-praga Brevipalpus phoenicis e do predador Agistemus brasiliensis a agroquímicos

Among the pests that attack coffee plants (Coffea spp.), it stands out some species of phytophagous mites which can cause significant losses, such as, Oligonychus ilicis (McGregor, 1917) (Acari: Tetranychidae) and Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae), vector of the coffee ringspot virus (CoRSV). Recent studies have indicated that stigmaeid mites, mainly of the genera Agistemus and Zetzellia, are important natural enemies of pest mites such as B. phoenicis and O. ilicis. The objective of this study was to evaluate the effect of various chemical compounds (insecticides, acaricides and fungicides) used in coffee and/or citrus plantations (or under registration) in Brazil on the mite pest B. phoenicis and the predator Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 (Acari: Stigmaeidae). Various pesticides were tested, using the concentrations recommended for the control of pests on coffee or citrus plants. The applications were performed in aPotter spray tower. It was evaluated the toxicity of chemicals on the adults of both mite species, besides the effect of compounds on the instantaneous growth rates (ri) of the mites. Abamectin, profenophos + cypermethrin, deltamethrin + triazophos, diafenthiuron, fenpropathrin, spirodiclofen and etoxazole were harmfull to B. phoenicis and A. brasiliensis. Cyflumetofen and malathion caused population reductions in B. phoenicis, but did not affect the population growth of A. brasiliensis.Thiophanate-methyl affected the population growth of both species, but was more toxic to A. brasiliensis. Copper oxychloride reduced only the population growth of the predaceous mite.Dentre as pragas que atacam o cafeeiro (Coffea spp.), destacam-se algumas espécies de ácaros fitófagos que podem causar perdas consideráveis, como por exemplo, Oligonychus ilicis (McGregor, 1917 (Acari: Tetranychidae) e Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae), vetor do vírus da mancha-anular do cafeeiro (CoRSV). Estudos recentes têm indicado que ácaros da família Stigmaeidae, principalmente dos gêneros Agistemus e Zetzellia, são importantes inimigos naturais de ácaros-praga, como B. phoenicis e O. ilicis. Objetivou-se, no presente trabalho, avaliar o efeito de diversos compostos químicos (inseticidas, acaricidas e fungicidas), utilizados em cafeeiro e/ou citros (ou em fase de registro) no Brasil, sobre o ácaro-praga B. phoenicis e o predador Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 (Acari: Stigmaeidae). Foram avaliados diversos agroquímicos, utilizando-os em suas concentrações recomendadas para o controle de pragas ou doenças em cafeeiro ou citros. As aplicações foram realizadas em torre de Potter. Avaliou-se a toxicidade sobre adultos de ambas as espécies, além do efeito dos compostos sobre a taxa de crescimento instantânea (ri) dos ácaros. Abamectina, cipermetrina+profenofós, deltametrina+triazofós, diafentiurom, fenpropatrina, espirodiclofeno e etoxazol foram altamente prejudiciais a B. phoenicis e A. brasiliensis. Ciflumetofem e malationa causaram redução populacional de B. phoenicis, mas não afetaram o crescimento populacional de A. brasiliensis. Tiofanato metílico afetou o crescimento populacional das duas espécies, mas foi mais prejudicial a A. brasiliensis. Oxicloreto de cobre reduziu apenas o crescimento populacional do ácaro predador

Toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis

The objective of this work was to evaluate the toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis. Mortality and growth rates of T. urticae and its predator were evaluated after applications of: abamectin, clofentezine, fenpropathrin, fenpyroximate, propargite, sulfur and spiromesifen, at their recommended concentrations; neem oils (Natuneem and Sempre Verde Killer Neem at 1%); and aqueous extracts at 10% of Dieffenbachia brasiliensis, Annona squamosa, Ruta graveolens, Agave angustifolia, Melia azedarach, Sonchus oleraceus, Mentha spicata x M. suaveolens, Allium cepa, Laurus nobilis, and Eucalyptus saligna. The acute toxicity and the influence of the compounds on the instantaneous growth rate of the mites were carried out in laboratory. Extracts of A. cepa, A. angustifolia, neem oil-based products, spiromesifen, propargite, fenpyroximate, abamectin and fenpropathrin caused mortality higher than 83% on T. urticae. Extract of A. angustifolia, Natuneem and clofentezine did not cause significant mortality rates on P. macropilis. Agave angustifolia and Natuneem did not affect significantly the growth rate of this predator. Propargite, fenpyroximate, abamectin, fenpropathrin, spiromesifen and extract of L. nobilis severely affected P. macropilis population