Potencial de Beauveria Bassiana no controle do Ácaro-da-necrose aceria guerreronis (Acari: Eriophyidae)

Abstract

The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is a key pest in coconut plantations. Chemical control is currently one of the most used strategies to control this pest. Faced with the various social, economic, and environmental problems caused by the use of pesticides, there is a need for environmentally viable alternatives for its control, such as entomopathogenic fungi. Thus, this work aimed to estimate the lethal concentrations of the Bb 032 strain of fungus Beauveria bassiana (Bals) Vuill (Moniliales: Moniliaceae) to the coconut mite and to evaluate the selectivity of neem oil, mineral oil, and lime sulfur on the mycelial growth of the fungus in vitro. These oils and lime sulfur are alternative pesticides used in the control of coconut pests, however their side effects on B. bassiana are yet to be studied. Six concentrations of the fungus were sprayed in arenas with mites to determine the lethal concentrations. Subsequently, concentrations of neem and mineral oils, and lime sulfur were micro pipetted in Petri dishes to determine their selectivity to the fungus. Data were subjected to PROBIT analysis to estimate the concentrations of the fungus B. bassiana to the coconut mite and to ANOVA repeated measures to estimate the selectivity of oils and lime sulfur to the fungus B. bassiana. The mean lethal concentration CL50 was 1.31x107 conidia/mL, and the CL80₀ was 2.04x10⁶. Neem oil and mineral oil were selective for B. bassiana (F = 79.6, p < 0.0001). Thus, B. bassiana has the potential to control the coconut mite, as well as neem and mineral oil can be used in the management of coconut pests without impairing micelial growth of the fungus, and possibly not affecting its efficiency in the control of the mite.