Biological control of pastoral pests using Acremonium spp. endophytes

Abstract

Although the role of the endophytic fungus Acremonium lolii in protecting the host plant from attack by insect pests, particularly Argentine stem weevil (Listronotus bonariensis), is often described in terms of plant resistance, it is a case of classical biological control. Endophytes in commercially available perennial ryegrass cultivars are acting as biological control agents against at least four pest species in New Zealand. Generally, endophyte adversely affects insect stages that feed on the above-ground parts of the plant, particularly those stages that feed near the base of the plant. It is apparent from insect feeding tests that there is no one universal anti-insect metabolite that will adversely affect all pest populations. It is therefore likely that an endophytelgrass combination that produces a cocktail of metabolites at low concentrations may be more useful than a combination that produces a very narrow suite of metabolites. Keywords: Acremonium spp., Listronotus bonariensis, Heteronychus arator, Costelytra zealandica, Wiseana spp., biological control, endophyte