Effects of Hexythiazox on Different Stages of Mites Infesting Orange Trees

Abstract

Miticidal action of hexythiazox has been investigated against three mites, Citrus Rust Mite, Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae), False Spider Mite, Brevipalpus californicus (Banks) (Acari: Tenuipalpidae) and Citrus Brown Mite, Eutetranychus orientalis Klein (Acari: Tetranychidae), infesting citrus trees in the region of Al Qassim, Saudi Arabia. Three concentrations of hexythiazox, half of the recommended dose (HRD), the recommended dose (RD) and double recommended dose (DRD) were used against the selected mite species at immature and adult stages. Mortality data was recorded after regular intervals of a day till seven days of post-treatment application. Larvicidal action of the pesticide was observed in terms of post spray percentage of egg hatching. Trails regarding mortality of immature and adult mites were carried out under laboratory and field conditions. A maximum of 72.88% and 64.41% mortality was observed in immature mites of P. oleivora at RD under laboratory and field conditions respectively. The highest mortality of adult mites at RD was recorded again in P. oleivora that was 18.97 and 20.39% under laboratory and field conditions respectively, showing that mortality percentage was insignificant in adults. Under the same conditions, mortality of mites observed at HRD was non-significant and there was negligible increase in mortality when concentration was increased from RD to DRD. Success of hatching for the treated eggs of the three selected mites was observed in the range of 5.00 to 12.50% at the recommended dose. This indicated that hexythiazox has the significant potential of inhibiting hatching process. For the successful control over citrus mites, the appropriate time of spray is prehatching stage