DINÂMICA POPULACIONAL DE Stomoxys calcitrans (DIPTERA: MUSCIDAE) E DETECÇÃO DA MUTAÇÃO kdr-his, ASSOCIADA À RESISTÊNCIA A PIRETROIDES, EM USINAS SUCROALCOOLEIRAS DO ESTADO DE SÃO PAULO

Abstract

In Brazil, outbreaks caused by the stable fly (Stomoxys calcitrans) are associated with sugarcane mill activities near livestock properties. The natural seasonality of this fly shows population peaks during hot and humid months of the year. To alleviate the effects caused by this pest, rural producers and sugarcane mills have widely adopted the chemical control, however its intensive use has led to the selection of resistant individuals. Therefore, the objective of the present study was to know the population dynamics and to evaluate the occurrence of the kdr-his mutation as a mechanism of pytrhroid-resistance of the stable fly to pyrethroid insecticides occurs due to. For the study, reflective traps were installed, which were collected and exchanged each time. seven days, in which specimens were identified and counted. The population dynamics of stable flies in sugarcane mills in the municipalities of Pereira Barreto (PB) and Sud Mennucci (SM), São Paulo presented different frequencies and the population peaks occurred in January, May/June and October/November. Thus, a close relationship was found between the control actions performed in the fertigated crops, in the composting yard and the quality in the management of animal production residues, and population abundance of the pest. The study to assess the occurrence of the kdr-his mutation in stable flies by allelespecific PCR was carried out in the municipalities of Buritizal (BTZ), Nova Independência (NI), Pereira Barreto (PB) and Sud Mennucci (SM), totaling 200 individuals. The total frequency of the kdr-his allele was 0.263, while the total genotypic frequency obtained was 0,480 for susceptible homozygote, 0,515 for heterozygote and 0,005 for kdr-his homozygote. The results showed that the kdr-his mutation is present in sugarcane mills in the state of São Paulo.