Locusts of the Year 2000 - 2

The fact that there have been no mass invasions of desert or migratory locusts for twenty years does not mean that the threat is over', we were warned in the cover article on the subject in the very first issue of Spore. That, as some of you may remember, was in March 1986. Where do we stand fourteen years later? Each year, locusts still destroy crops in developing countries. Between 1986 and 1988, desert locusts (Schistocerca gregaria) invaded African countries north of the Sahara. They moved from east to west, and then up to northern Africa before crossing the Atlantic and striking the West Indies and South America in October 1988. But for Africa there was only a short respite. New invasions hit the countries of the Sahel (in particular Mauritania and Sudan) in 1993-1994 and again in 1998. The plagues were smaller in scale than previous ones, and they were soon brought under control. In the case of migratory locusts (Nomadacris septemvasciata), their invasions have been more localised, as seen in the Lake Chad basin since 1997, and in Madagascar where 80% of the country has been pillaged by locusts (see Spore 76). Other locusts have made themselves noticed by moving out of their usual breeding areas: outbreaks of Senegalese locusts have been reported in Tanzania and Zambia since 1995. Forewarned, forearmed Anti-locust measures are normally taken by national agencies for plant protection, and by inter-regional bodies. Without any external support, these bodies are unable to bear the high costs of the measures and thus call for assistance from FAO, or directly from national donor agencies. In the period from 1986 to 1993, anti-locust measures covering 30 million hectares in Africa have cost a total of E 375 million, and 85% of this cost has been met by the international community. Although the expenditure on anti-locust measures is decreasing in Africa, this does not mean that the problem has been solved once and for all. The risk has moved elsewhere, but a calamity is a calamity, whatever its scale, and it always has a high cost. Emergency aid now consists of providing the products, equipment and materials necessary for fighting locust invasions: vehicles, protective clothing, insecticides and so on. Since 1989, research has been underway on finding products which are less harmful to the environment than chemical insecticides: one example is biopesticides based on pathogenic fungi. Here work is being done by a group of international organisations known as LUBILOSA (from the French for biological fight against locusts and crickets ) which has developed a natural insecticide from the spores of an African fungus, Metarhizium flavoviride. It is known commercially as Green Muscle (see Spore 78) but, being produced in only Niger and Benin, is little used. It is regarded as one of the most interesting biological alternatives to chemical insecticides but it is not as effective, especially in dealing with massive outbreaks, and it is being mainly used in preventive measures. It is, in fact, in prevention where a major role needs to be played. In 1994, the FAO, which coordinates all anti-locust measures, set up a programme involving several agencies including the German GTZ and French CIRAD. Based in the EMPRES system (Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases), it aims at improving the means of tracking plagues, through a monitoring body (the Locusts Group) which watches out for invasions. The programme has provided practical and theoretical training to people working in anti-locust measures. Another possibility for monitoring is through the use of satellites which can assess the state of affairs in isolated areas, where it is hard to get on-the-spot data, and predict hot-spots. And modelling, a technique worked on by the research community since 1990, provides a faster way to locate high risk zones and to intervene appropriately. The modelling technique involves constructing computer models using data that show similarities or commonalities appearing in two countries (same vegetation, same climate and same species of locusts). Soon modelling will be able to include locust movements using data on winds and land contours. Already, in Madagascar rainfall data have been used in developing a model for use in any countries which have similar climatic and environmental conditions to those on the island continent and which are conducive to invasions of migratory locusts. The case of Madagascar has shown that there are many problems to overcome. They are political (disagreements about strategy), financial (the high cost of maintaining control bodies during inactive periods) and technical (lack of materials, products and personnel). In general, it is that lack of continuity in monitoring and prevention in the quiet times between critical periods which is a cause for concern. It is, as we know, the quiet ones that you have to watch out for For further details: Fight against locusts in Africa, GTZ, Postfach 5180, 65726 Eschborn, Germany Fax: + 49 6196 79 7413 Email: stephan.krall@gtz.de FAO, EMPRES - Desert Locust Information Service Website: www.fao.org. CIRAD-Prifas BP 5035 34032 Montpellier Cedex 1 - FranceLocusts of the Year 2000 'The fact that there have been no mass invasions of desert or migratory locusts for twenty years does not mean that the threat is over', we were warned in the cover article on the subject in the very first issue of Spore...