Mycoinsecticide for grasshopper and locust control
The long-running project, LUBILOSA (LUtte BIologique contre les LOcustes et SAutériaux), has recently seen its efforts crowned with success - this time with the launching of two commercial products based on the entomopathogenic fungus Metarhizium anisopliae (flavoviride) for the control of grasshoppers and locusts.
Locusts are amongst the most dramatic and devastating of the insect pests. Locusts swarms can cover more than 1000 km2 and cause immense damage as they progress across the countryside. Locust control is therefore the subject of intense political interest, especially during outbreaks and both national authorities and donor communities have been keen to develop control methods that are less insecticide dependent and more environmentally friendly. (In the last major desert locust plague in the 1980s, which affected large areas of northern Africa, the Middle East and Western Asia, $250 million was spent on application of broad spectrum, chemical pesticides, which achieved only limited control but caused widespread concern about environmental pollution). So, after years of careful research and extensive trials, it now seems that entomopathogenic control could provide a very effective solution.
The LUBILOSA team, comprising researchers from CABI Bioscience and CILSS (Comité Permanent Inter-Etat de Lutte contre las Sécheresse dans le Sahel) as well as IITA, last year carried out large-scale trials of Metarhizium anisopliae (flavoviride) against grasshoppers in Niger and Mali. The fungal product proved as effective as conventional pesticides, while causing less environmental damage, and was preferred by farmers. Trials against variegated grasshopper in more humid areas also yielded encouraging results.
One of the principal successes of the LUBILOSA project has been to show that the requirement for humid conditions for the fungus to work can be avoided by spraying fungal spores in oil so that, even under desert conditions, the spray can be used to kill locusts. The spray can also be applied using the existing Ultra Low Volume (ULV) spinning disk spray equipment used for spraying chemical pesticides.
Although the fungal spray is used like a chemical insecticide, its effects are not immediate. Grasshoppers and locusts take 6-10 days to die but the insects are greatly incapacitated during this time - eating and moving far less than healthy insects. The spray also persists in treated vegetation (depending on environmental conditions the spores can survive up to several weeks and continue to be a source of infection). This effect reduces the number of treatments required and is therefore more cost-effective than using many repeated applications of chemical pesticides.
Enthusiasm for the potential of entomopathogens as practical biological control agents is reflected in ongoing trials of other species of fungi against cassava green mite, storage pests, termites and banana weevil.
