Detecção e caracterização da resistência de Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae) ao acaricida propargite. / Detection and characterization of Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae) resistance to the acaricide propargite.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The citrus flat mite Brevipalpus phoenicis (Geijskes) is one of the most important citrus pests because it vectors the citrus leprosis virus. The acaricide propargite has been frequently used to control this mite. Therefore, the objective of this work was to collect basic information for implementing a resistance management program of B. phoenicis to propargite. In this work it was conducted studies on baseline susceptibility of B. phoenicis to propargite, monitoring the susceptibility to propargite in different B. phoenicis populations, characterization of propargite resistance in B. phoenicis and evaluation of interaction of B. phoenicis, propargite and citrus. The bioassay technique used in this study was the residual contact with the use of citrus leaf disks sprayed with the Potter spray tower. The estimated LC50 (95% CI) to susceptible (S) and resistant (R) strains were 217.51 (207.07-228.35) and 2,195.43 (1,759.23-2,808.21) mg of propargite/ml of water [A.I. (ppm)], respectively. The resistance ratio was 10-fold. The diagnostic concentrations defined for monitoring the resistance were 320 and 720 mg of propargite/ml of water [A.I. (ppm)]. A significant difference in susceptibility to propargite was detected in B. phoenicis populations. Studies on evaluation of interaction of B. phoenicis, propargite and citrus revealed that the mode of exposure of mites by residual contact gave better discrimination between S and R strains than by direct contact under laboratory conditions. The persistence of biological activity of propargite on citrus fruit was low under field conditions and there was a clear discrimination between S and R strain on propargite residues, suggesting that the evolution of resistance can be processed mainly by the residual contact of B. phoenicis on propargite.

ASSUNTO(S)

citrus leprosis virus ácaro-vetor-de-doença-de-planta leprose cítrica resistência ao acaricida acaricide resistance mite vector of plant disease

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