Locusts: protecting thornbushes or feeding people - a choice

Rafik Skaf Dr Rafik Skaf, who retired in January 1988, worked for 23 years at FAO where since 1980, he was Director of the 'Locusts, Migrating Pests and Emergency Operations Group'. He was previously Director of Plant Protection for 16 years in Syria, his native country. A new wave of an old menace is threatening Africa. After the drought and the grasshoppers, it is now the migrating locusts that are invading sub-Saharan Africa and the Maghreb. However, this imminent disaster was predictable and could have been avoided. People more than fate are largely responsible for this 'disaster in the making'. The last major invasion of migratory locusts ended in 1963. Since then, the preventative action plan implemented with the help of FAO enabled crop damage to be kept to a minimum. The swarms of locusts sighted were systematically destroyed by the application of a powerful pesticide, dieldrin. This product is not only very efficient but also inexpensive. In fact, it has a strong residual effect, remaining active more than a month, and the required doses are low: 20-30 g of active ingredient per hectare. Applications in bands spaced several hundred metres apart suffice to kill the locusts, particularly their larvae, over vast zones. Dieldrin is certainly very toxic for mammals and birds but the applications are done only in deserted arid regions where locusts are found when they are not migrating. There have been no human deaths attributed to such use of dieldrin since it began to be used 30 years ano. The fact is that there is no ready alternative to this chemical: studies are under way but no new product will be available for a year or two. However, environmental considerations over the past few years have prompted several countries, such as those in North Africa, to ban its use in agriculture. Not having suffered from locust invasions, the effect of this ban was hardly noticed. Furthermore, the drought between 1983 and 1985 resulted in the lowest recorded levels of locusts in more than 50 years. Since September 1985, however, favourable climatic conditions have facilitated their rapid multiplication along the coasts of the Red Sea. Control programmes have not been able to eliminate these populations entirely because military considerations (notably in Eritrea) meant that not all infested regions could be treated. During the summer of 1986, the locusts continued to reproduce in Sudan and Mauritania. Some control efforts were made but there was little use of dieldrin. The countries concerned mostly used organophosphates supplied by the international community to control the grasshoppers that constituted a serious threat that year. From June to September 1987, the abundant rains that fell in northwest Sudan and northeast Chad favoured a new explosion of this serious pest. In August 1987, the concentration of locusts in northern Chad was the only opportunity to destroy them in order to prevent the looming invasion. Unfortunately, this opportunity was not used. During the meeting of donors and governments in Rome, specialists proposed the elimination of these menacing swarms by applying dieldrin in bands. This operation would have meant 15 days of treatment by a large aircraft at a cost of about half a million dollars. Some donors, such as the USA and several northern European countries, preferred a month-long operation involving several large aircraft and costing about six million dollars... By refusing to sanction the use of dieldrin, they effectively recommended the use of fenitrothion, an insecticide with low persistence that kills only those insects directly sprayed. The infested zones must therefore be treated in their entirety, which requires much larger quantities of insecticide and greater transport facilities. This was a practically impossible task in such vast (500,000 ha) and isolated areas. The locusts that escaped treatment were thus able to continue their migration towards the west reaching Niger and Mali and, in October, Morocco. These countries were then obliged to organize intensive efforts, costing several million dollars, to stop the locusts from invading their cultivated areas. Algeria was also forced to treat some locusts that arrived in the southern part of its territory. At the same time, other locust swarms formed and invaded Mauritania in the first months of 1988. Land-based control operations were undertaken but it quickly became obvious to FAO (which subsequently advised the Mauritanian government) that only dieldrin treatment in bands over the entire affected region could control the invasion. But as in Chad, Niger, and Mali, the donors persuaded the government not to use dieldrin. When the first rains arrived in March, these locusts migrated from Mauritania towards Morocco and Algeria, which were forced to launch a second control programme. When the rainy season arrives, it will be the sub-Saharan countries that will be next in line. No-one knows yet just where and when this invasion will stop given the great ability of locusts to travel. A new generalized invasion seems imminent and it will only be able to be stopped at prohibitive cost. Furthermore, the application of massive doses of insecticides over inhabited areas which will be needed also poses risks for the environment which are much more dangerous than the proposed use of dieldrin in the desert In fact, whether due to lack of information or understanding, the decision-makers have saved the locusts by refusing to sanction the use of control measures that have previously proven their effectiveness. The situation is now urgent and there is no time left to beat about the bush. Several countries still have dieldrin stocks and the means to apply them. They must be able to do so without being advised otherwise by countries that have nothing to fear from locust invasions There is no time left to mince words: do we have the right to let famine return to these already impoverished regions under the pretext of nature conservation? Is not an ear of corn grown to help feed one's family worth at least as much as a desert thornbush? When human lives are at stake, people must assume responsibility for their decisions in full knowledge of their impact.Rafik Skaf Dr Rafik Skaf, who retired in January 1988, worked for 23 years at FAO where since 1980, he was Director of the 'Locusts, Migrating Pests and Emergency Operations Group'. He was previously Director of Plant Protection for 16 years in..