Control of the banded fruit weevil Phlyctinus callosus (Coleoptera: Curculionidae) using entomopathogenic nematodes

Abstract

AbstractPhlyctinus callosus (Schönherr), the banded fruit weevil, is a key pest of deciduous fruit and grapevine in the Western Cape province of South Africa. Entomopathogenic nematodes (EPNs), as a biocontrol agent, are found to be effective in controlling both soilborne and above‐ground insect pests. Different EPN species were screened for virulence against different life stages of P. callosus, followed by a field trial, in which Steinernema yirgalemense was applied at different concentrations. S. yirgalemense, Heterorhabditis noenieputensis and the exotic Steinernema feltiae gave good control of P. callosus larvae at 100 infective juveniles per insect, with no significant difference between treatments. In the case of P. callosus pupae, Heterorhabditis indica (70%) and Heterorhabditis baujardi (67%) differed significantly (P < 0.05) in their control, compared with H. noenieputensis (55%). H. indica (95%) and S. yirgalemense (94%) gave significantly higher (P < 0.05) control of P. callosus adults, compared with the three other nematode species tested. In the field trials, S. yirgalemense, at 20 and 40 infective juveniles/cm2, gave 69% and 78% control of P. callosus larvae after 48 h of exposure, respectively. The results indicated that all EPNs tested were effective against the immature and adult stages of P. callosus, with differences in mortality among the EPN species tested. S. yirgalemense, at low concentration, can effectively control P. callosus under field conditions, but large‐scale field trials are recommended to demonstrate the potential use of this biocontrol agent within integrated pest management programmes.