P-078 - Reduction of Cylas formicarius Using the Entomopathogenic Fungus Metarhizium anisopliae

Cylas formicarius, the sweetpotato weevil (SPW), causes significant yield loss in sweetpotato across the world, including Hawaii. As a cryptic insect, SPW can be difficult to manage, consequently soil-borne fungi such as Metarhizium anisopliae are attractive tools. Metarhizium anisopliae KO-002, isolated on Oahu, Hawaii, was evaluated for managing SPW. Laboratory choice arena tests indicated KO-002 suppressed SPW feeding of sweetpotato. When inoculated with KO-002 spores in the greenhouse, sweetpotato resprouted sooner and had more vegetative growth than uninoculated sweetpotato. KO-002 was tested in the field as a compost amendment at sweetpotato planting. At midseason, sweetpotato vigor was greater and plants were taller in plots receiving compost amended with KO-002 compared to those in unamended compost plots (P≤0.05). However, sweetpotato yield was not different between amended and unamended compost treatments (P>0.05). Sweetpotato grown in plots receiving compost amended with KO-002 had reduced SPW damage (P≤0.05) and supported lower SPW population densities compared to sweetpotato not grown in amended compost (P≤0.05). KO-002 enhances sweetpotato growth and reduces populatons of C. formicarius. Metarhizium anisopliae KO-002 is a promising component for integrated management of SPW for sweetpotato grown in Hawaii.