Potential of a dried rice/mycelium formulation of entomopathogenic fungi to suppress subterranean pests in small fruits

The potential of a dried rice/mycelium formulation of three species of entomopathogenic fungi (Metarhizium anisopliae, Beauveria bassiana and Paecilomyces farinosus) was assessed according to five criteria: storage life, field efficacy against two subterranean pests of cranberry, persistence and efficacy against first-instar black vine weevil larvae in potted strawberry and field persistence in a cranberry bog. The number of conidia sporulated from the formulation did not decline between 4 and 20 days. In small plot field trials, the numbers of black vine weevil, Otiorhynchus sulcatus (F.), were significantly lower in plots treated with 1000 gm(-2) of formulated M. anisopliae than in untreated plots. In similar trials, the numbers of adult cranberry girdler Chrysoteuchia topiaria (Zeller), inside emergence cages were significantly lower on plots treated with the formulated M. anisopliae than on untreated plots. The formulation suppressed first-instar black vine weevil larvae in potted strawberry regardless of the species of entomopathogenic fungus or the post-inoculation interval. M. anisopliae was periodically isolated for up to 637 days from plots in cranberry bogs treated with the formulation. In general, the dried rice/mycelium formulation may be a useful fungal mycopesticide for the management of subterranean pests of small fruits, especially if applied at high rates to areas of serious pest infestation.