Sweet potato Ipomoea batatas (L.) storage practices used in southern Benin and the use of entomopathogenic nematodes to control sweet potato weevil (Cylas puncticollis Boheman) under laboratory conditions

Abstract

A survey was conducted in 2013 in sweet potato (SP; Ipomoea batatas (L.)) fields in Benin to record SP tuber storage practices and assess the efficacy of indigenous isolates of entomopathogenic nematodes (EPN) for the control of SP weevils (Cylas puncticollis). The SP tubers werestored in rooms, mounds, stores, or kitchens for 2–28 weeks. Tuber damage severity varied with surveyed site between 38.0% (low damage) and 6.3% (low to moderate damage). Under laboratory conditions, weevil population increased up to 23.53 times inside tubers and tuber weight loss reached 71.64% with maximum tuber powder of 2.86g. Nematodes were foundto efficiently suppress SP weevils inside tubers and to reproduce inside the host giving up to 2193.42 nematodes per insect larvae. Damage to tuber pieces, weevil and EPNprogeny production, and percentage weight loss of tubers varied significantly (P≤0.05) among EPN isolates. These results showed EPN are promising candidates for successful SP weevil control in Benin.