Integrated pest management and sustainable agriculture — a moving feast of challenges for northern Australian grain/pulse industries

Abstract

Northern Australian pest management is a moving feast for the Grain/Pulse industries. Key challenges include changing pest behaviour, the southward movement of some pests, changing agronomic practices, and the risk of insecticide resistance in new IPM compatible insecticides. Changed pest behaviour includes lucerne seed web moth (Etiella behrii) attacking vegetative soybeans and its increased incidence in podding mungbeans and soybeans. Changing pest distribution is illustrated by soybean stem fly (Melanagromyza sojae), previously a tropical pest in Australia, with major recent outbreaks in the Northern Rivers region of NSW. Confounding the impact assessment of this pest were concurrent outbreaks of plant pathogens such as charcoal rot (Macrophomina phaseolina), which produces sudden death plant symptoms often attributed to stem fly. Changed agronomic practices impacting on pest management include zero till cultivation and the move to narrow row spacing (< 50 cm) to boost yield. Zero till greatly increases the overwintering survival of lucerne crown borer (Zygrita diva), a stem boring beetle in soybeans that overwinters in soybean stubble, and the black soil scarab (Othnonius batseii), which is becoming a major issue in maize and sorghum crops. Narrow rows have implications for pest sampling, with potentially greater pest count variability. Lastly, the high effectiveness of new group 28 caterpillar insecticides threatens their overuse and the subsequent development of resistance in their key target, the corn earworm Helicoverpa armigera. This paper outlines the latest research that is addressing the above issues, and also identifies research gaps, including areas where international collaboration would benefit.