ECOLOGY AND BIOCONTROL STUDY ON THE WHITE GRUBS, PENTODON BISPINOSUS INFESTING STRAWBERRY ROOTS

Abstract

An ecological study was conducted to elucidate the peaks of the white grubs’ larvae infesting strawberry roots along one year from May 2020 to April 2021. Furthermore, feeding and control study was applied under laboratory conditions. Results revealed that May and September months recorded 20 larvae per root of strawberry plant as the highest numbers of larvae under 17-38°C and 32-61 RH%. The larvae of the Pentodon bispinosus were reared on three vegetable roots; however, the grubs have a wide range of host families. The larvae of the P. bispinosus prefer the roots of the Strawberry plants recording the highest weights as 7 ± 0.6 g roots/day. Bioinsecticides were tested to determine the most effective agents against white grubs, from the results, the third stage of grubs have resistance against Abamectin 3.6 % and Chitosan. Abamectin 3.6% EC recorded 30% reduction in larvae population after 3 days of treatment decreased to 10% after 30 days, on contrary, Chitosan recorded zero reduction.