Sap beetles and mycotoxins in maize.

Sap beetles (Coleoptera: Nitidulidae) are important in vectoring mycotoxigenic species of Aspergillus and Fusarium to maize. Species examined are attracted to fungal and maize volatiles, and are resistant to most mycotoxins compared to maize ear-infesting caterpillars. They will invade ears damaged by birds or caterpillars or those ears that have poor husk coverage. An integrated control programme for these insects under development presently includes pheromones and host coattractants for trapping; identification and dispersal of pathogenic nematodes and fungi; identification of maize varieties cross-resistant to mycotoxigenic fungi and other insects, and the potential mechanisms involved; and formulations of insecticides for single treatment, low active ingredient, selective control of insect pests of ears including sap beetles and caterpillars that preserve naturally occurring predators and parasites. Autoinoculative devices are also being tested to use sap beetles to deliver biocompetitors of mycotoxigenic fungi to maize.