Mycopesticides as part of integrated pest management of locusts and grasshoppers

Abstract

The search for alternatives to the widespread use of chemicals to control locusts and grasshoppers has led to the development of mycoinsecticides based on Metarhizium anisopliae var. acridum. Two products are available commercially: Green Muscle® in Africa and Green Guard® in Australia. Only Green Guard® has been used in large control operations, with nearly 80,000 ha treated since operational use began in 2000. Research, though important, was not sufficient to lead to operational use of Green Guard®: the critical factor was the formation of the Locust and Grasshopper Biocontrol Committee that consisted of research providers, end-users and a commercial partner who together favored the rapid development of a commercial product.In Australia, M. a. var. acridum is used in environmentally sensitive areas such as near waterways, or where there are rare and endangered species, and on the many properties, in locust-source areas in the interior, that produce organic beef for export. However, an increasingly important use is by landholders, who are now required to list all the chemicals used for pest control when they sell their products. This, potentially very large, use is limited by the myopesticide's slower action and higher price.Slower action is not a major problem when Metarhizium is used in preventive control programs. The higher price is, in part, a consequence of its narrow host range. M. a. var. acridum is specific to locusts and grasshoppers, so research, development and registration costs must be divided amongst 1 or 2 users, not dozens, as is common with chemical pesticides.Yet one of the greatest problems is the sporadic nature of locust and grasshopper outbreaks, which results in an intermittent need for Metarhizium and a lack of ready availability when outbreaks do occur. Use of Metarhizium in a number of countries, including those that have more regular outbreaks, may be one way of ensuring high-volume production at a reasonable price. Only then will there be a regular operational use to prove that this mycoinsecticide works under a wide variety of environmental conditions, so that it can take its place as part of the integrated pest management of locusts and grasshoppers throughout the world.