Selection of a fungal isolate for the control of the pink hibiscus mealybug Maconellicoccus hirsutus

Background Maconellicoccus hirsutus Green is a widely distributed pest of numerous crops. Although synthetic pesticides are used to control this pest, entomopathogenic fungi may provide an alternative control mechanism. Three experiments were carried out to select a fungal isolate with the potential to be used as a microbial control agent. The in vitro growth of five isolates of Beauveria bassiana sensu lato (Bals.) Vuill and Metarhizium anisopliae sensu lato (Metschn.) Sorokin, along with three isolates of Lecanicillium lecanii (Zimm.) Zare & W. Gams and Isaria fumosoroseus (Wize), was assessed at four temperatures. The in vivo sporulation of eight selected isolates was then evaluated, followed by the susceptibility of third-instar M. hirsutus to a single dose (1 x 108 conidia mL-1) of each of these isolates. Results Growth was greatest by isolates of I. fumosoroseus and L. lecanii at 15 and 20 degrees C and by isolates of M. anisopliae at 25 and 30 degrees C. In vivo conidium production was greatest when infected with B. bassiana isolate GHA and M. anisopliae isolate Ma65. Mortality was greatest when inoculated with M. anisopliae isolates Ma65 and Ma129. Conclusion Isolate Ma65 shows the best potential to be developed as a microbial control agent for M. hirsutus.(c) 2012 Society of Chemical Industry