A Review of the Biology and Control of Phlyctinus callosus (Schönherr) (Coleoptera: Curculionidae), with Special Reference to Biological Control Using Entomopathogenic Nematodes and Fungi

Abstract

The banded fruit weevil (BFW), Phlyctinus callosus (Schönherr) (Coleoptera: Curculionidae), is a polyphagous pest, feeding on a number of plant groups, like grasses, weeds, herbs, and woody plants. Phlyctinus callosus is indigenous to South Africa and has a limited distribution throughout the world. The weevil was only reported in the Western Cape, South Africa, New Zealand and Australia. Where the BFW occurs, it is a major insect pest of grapes and deciduous fruit, causing damage by feeding on the leaves and fruit, including the fruit stalks and shoots. The BFW adults, especially, cause fruit damage by means of feeding on the skin and the underlying flesh, which results in the formation of shallow lesions with phytosanitary implications. Other damage includes foliage damage, berry scarring and ringbarked stems, due to feeding activity. Control has mainly been achieved through the use of trunk barriers, which are effective in preventing the weevil from reaching the fruits, although such use is labour-intensive. Biocontrol agents, like entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPF), are preferred alternatives, because they have no negative effect on the environment, and because they leave no residues in the fruit intended for export. Using biological control agents in combination to control insect pests emphasises the importance of knowing the biology of the target insect pest, as well as that of the biocontrol agents, such as EPNs and EPF.