enormous numbers of insects in the swarms and hopper bands. Farmers often try mechanical means of killing locusts, such as digging trenches and burying hopper bands, but this is very labour-intensive and is difficult to undertake when large infestations are scattered over a wide area. Farmers also try to scare locust swarms away from their fields by making noise, burning tires, or other methods. This tends to shift the problem to neighbouring farms, and locust swarms can easily return to reinfest previously visited fields. Biopesticides Biopesticides include fungi, bacteria, neem extract, and pheromones. The effectiveness of many biopesticides equals that of conventional chemical pesticides, but two distinct differences exist. Biopesticides in general take longer to kill insects, plant diseases, or weeds, usually between 2 and 10 days. The two types of biopesticides are biochemical and microbial. Biochemical pesticides are similar to naturally occurring chemicals and are nontoxic, such as insect pheromones used to locate mates, while microbial biopesticides, come from bacteria, fungi, algae, or viruses that either occur naturally or are genetically altered. Entomopathogenic fungi generally suppress pests by mycosis - causing a disease that is specific to the insect. Biological control products have been under development since the late 1990s; Green Muscle and NOVACRID are based on a naturally occurring entomopathogenic fungus, Metarhizium acridum. Species of Metarhizium are widespread throughout the world, infecting many groups of insects, but show low risk to humans, other mammals, and birds. The species M. acridum has specialised in short-horned grasshoppers, to which these locusts belong, so has been chosen as the active ingredient of the product. The product is available in Australia under the name Green Guard and in Africa, it used to be available as Green Muscle. However, since Green Muscle seems to have disappeared from the market, another product, NOVACRID, was developed for Africa, Central Asia, and the Middle East. These products are applied in the same way as chemical insecticides, but do not kill as quickly. At recommended doses, the fungus can take up to two weeks to kill up to 90% of the locusts. For that reason, it is recommended for use mainly against hoppers, the wingless early stages of locusts. These are mostly found in the desert, far from cropping areas, where the delay in death does not result in damage. The advantage of the product is that it affects only grasshoppers and locusts, which makes it much