Efficacy of the fungus Purpureocillium lilacinum applied via drone onto pasture for controlling the tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

In the southeastern region of Brazil, ticks of the species Rhipicephalus (B.) microplus are constantly present on cattle throughout the year. This is due to climatic conditions that favor the biology of these ticks and resistance to the acaricides in use that has developed. The aim of this study was to evaluate the efficacy of the fungus Purpureocillium lilacinum (IBCB 130) in powdered form, applied via a drone, from the bioFUNGUS spray dispenser (NCB Sistemas Embarcados Ltda), onto pasture for controlling these ticks. This experiment was conducted at Aptaregional, Regional Research and Development Unit of Pindamonhangaba, São Paulo, Brazil. To evaluate the efficacy of treatment, two groups were formed (treated and control), each with ten calves of the Girolando breed, which were kept in two separate paddocks in which the main grass species was Brachiaria decumbens. The treated paddock received seven monthly applications (November–May) of the fungus Purpureocillium lilacinum (5 g de P. lilacinum in 200 g of wheat flour). The control paddock did not receive any treatment. Tick counts performed on the animals every two weeks showed that, over the entire period, the treatment had a mean efficacy of 48.59 %. The months of December and January presented the highest efficacy rates, of 63.50 % and 83.87 %, respectively.