by Michel Lecoq
Locust invasions are a major threat to the agriculture, pasture, food security and social stability of rural populations occupying a very large area from Western Africa to Northern India. Large amounts of chemicals are being used to check this plague, at considerable risk to the environment and public health. As a hazard locusts depend on the wind and rain to travel.
West African countries and the Maghreb recently had to cope with a dramatic invasion. In summer 2003 highly favourable rains over the whole Sahel area caused widespread outbreaks. Locusts quickly changed from the solitary phase - inoffensive and confi ned to the Saharan zone - to the gregarious phase characterised by hopper bands and destructive swarms. All the affected countries have specifi c national units to survey and control the insect, but the ones in the Sahel are recent arrivals and are chronically short of resources. They reacted immediately but lacked adequate funding. In October 2003 affected countries and the FAO launched an appeal for donors but the international community only responded several months later. By then the invasion was in full swing. The funds required to prevent damage to vegetation rose from $10m to $50m, and ultimately $100m.
Early chemical treatment would have suf- fi ced for countries in the Sahel and only cost $1m. The recurrent costs of prevention only add up to a few percent of emergency assistance for curative control. By the end of 2004, nearly 8m hectares had been treated with insecticides... without stopping the invasion.
Since the 1960s effi cient control practices have proved successful. Before then, locust invasions were almost continuous and could last for many years. Early treatment and control techniques, as well as preventive strategies have clearly reduced the length of invasions. In 45 years only two invasions (1987-89 and the current invasion) could not be stopped at an early stage. Preventive control is recognised as the only reasonable global strategy. It involves regular surveys of outbreak areas (where invasions originate) and early control operations against the fi rst hopper bands and swarms, when they are still of limited size and a long way from crop areas. This strategy, recommended by the Desert Locust Control Committee and FAO, proposes a permanent national capacity for survey and control. It also requires coordination at a regional level, and information centralisation and data analysis under the aegis of the FAO’s Locust Group.
The 1987-89 invasion highlighted the need to strengthen the preventive system. It was launched in 1994 as the Desert Locust component of FAO’s EMPRES programme, of which the top priority was to reinforce early-warning and response capacity for locust control at a national level and develop regional cooperation. EMPRES was implemented in 1997 in countries around the Red Sea, an area where many past invasions have originated and considered a high priority. Unfortunately for West Africa and the Maghreb it proved impossible to fi nd the necessary funds in time and the programme has so far only been partly implemented.
The current crisis once again pinpoints the shortcomings in preventive control in Western Africa. National survey and control capability needs to be rebuilt. But real emergency plans are also required, backed by an international trust fund. Furthermore we need an effi cient governing body associating affected countries and donors. This is the only way to insure the long-term sustainability of preventive strategy.
Michel Lecoq is a researcher at the Centre for Agricultural Research for Developing Countries (CIRAD) at Montpellier University.