Development of Metarhizium-based biopesticides for sugarcane pest management - current progress and future prospects

The fungus Metarhizium anisopliae is a naturally-occurring pathogen of soil insects in Australia. Metarhizium can be used as a biopesticide by mass-producing spores on rice and applying the resulting product into canefields. Numbers of grey back canegrub in plant cane have been consistently reduced by more than 50% when spores of isolate FI-1045 together with the rice medium have been applied at 33 kg/ha. About 9 t of this product has been applied in 1997 and 1998. It is hoped that the product will be registered as BioCaneTlII by 2000. FI-1045 has also given some control of southern oneyear canegrub. Another isolate, FI-147, has significantly reduced numbers of negatoria canegrub the year after application into sugarcane ratoons, and increased cane yield. The same isolate is equally effective against French's canegrub in laboratory bioassays, and field trials are in progress. Trials have been less successful against Childers canegrub, and more effective isolates must be identified for this species. Trial results have been very poor against soldier fly; none of the isolates tested in bioassays was very virulent, and no further work is planned against this pest. Future work intends to optimise the control provided by FI-1045 against greyback canegrub, develop FI-147 for both negatoria and French's canegrub, improve the efficiency of Metarhizium production, and develop better formulations and packaging systems.