Purple and leprosy mites are sensitive to high concentrations of bifenthrin, dimethoate and flupyradifurone

Research carried out in the laboratory at the Professional Master's Degree in Citrus Disease and Pest Control - MasterCitrus, from Fundecitrus, investigated the effect of three insecticides applied to control the psyllid, bifenthrin (30 g ai/2000L), dimethoate (1200 g ai/ 2000L) and flupyradifurone (100 g ai/2000L), in the population increase of purple mites (Panonychus citri) and leprosis (Brevipalpus yothersi). The results showed that the mites are sensitive to the recommended concentrations for the psyllid (~50% mortality) and to high concentrations (>80% mortality). However, females of P. citri e B. yothersi exposed to subdoses* of bifenthrin and/or flupyradifurone produced more eggs than females exposed to the control treatment (water). On the other hand, no significant effect was observed on the reproductive capacity of females. P. citri e B. yothersi in dimethoate treatments. This study was carried out throughout 2018 by agricultural engineer Aloisio de Padua M. Costa.

According to the project advisor, Fundecitrus postdoctoral fellow Odimar Zanuzo Zanardi, the results help in choosing the most appropriate insecticide for managing the psyllid in the presence or absence of mites. “As psyllid control is common, knowing the effects of these compounds prevents the emergence of a new problem, the increase in the mite population,” he says.

*Subdoses are doses lower than those recommended for controlling the psyllid. This process is the result of the natural degradation of insecticides after application in the field. Therefore, in this study, concentrations corresponding to 6 were used as subdoses; 12; 25 and 50% of the recommended dose for psyllid control.