Biopesticides
Biopesticides include fungi, bacteria, neem extract and pheromones. The effectiveness of many biopesticides equals that of conventional chemical pesticides, but there are two distinct differences. Biopesticides in general take longer to kill insects, plant diseases, or weeds, usually between 2 and 10 days.
There are two types of biopesticides - 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 like Green Muscle 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.
A biological control product has been under development since the late nineties. It is based on a naturally occurring entomopathogenic fungus (i.e. insects-infecting fungus), Metarhizium acridum. Species of Metarhizium are widespread throughout the world, infecting many groups of insects, but show a low risk to humans, other mammals and birds. The species M. acridum has specialised on short-horned grasshoppers, to which group locusts belong, and has therefore been chosen as the active ingredient of the product.
The product is available in Africa under the name Green Muscle and in Australia as Green Guard. It is applied in the same way as chemical insecticides, but does not kill as quickly. At recommended doses, the fungus can take up 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 safer than chemical insecticides. Specifically, it allows the natural enemies of locusts and grasshoppers to continue their beneficial work. These include birds, parasitoid and predatory wasps, parasitoid flies and certain species of beetles. Though natural enemies cannot prevent plagues, they can limit the frequency of outbreaks and contribute to their control. Biopesticides are also safer to use in environmentally sensitive areas such as national parks or near rivers and other water bodies.
Green Muscle was developed under the LUBILOSA Programme, which was initiated in 1989 in response to environmental concerns over the heavy use of chemical insecticides to control locusts and grasshoppers during the 1987-89 plague. The project focused on the use of beneficial disease-causing microorganisms (pathogens) as biological control agents for grasshoppers and locusts. These insects were considered to be too mobile and to reproduce too fast to be readily controlled by classical biological control. Pathogens have the advantage that many can be produced in artificial culture in large quantities and be used with ordinary spraying equipment. Entomopathogenic fungi were traditionally seen as needing humid conditions to work well. However, the LUBILOSA Programme found a way to avoid this by spraying fungal spores in an oil formulation. Even under desert conditions, Green Muscle can be used to kill locusts and other Acridid pests, such as the Senegalese grasshopper. During recent trials in Algeria and Mauritania (2005 and 2006), various natural enemies, but especially birds, were abundant enough to eliminate treated hopper bands in about a week, because the diseased hoppers became sluggish and easy to catch.
Read more about this topic: Desert Locust