IN Kenya, scientists would rather outsmart insects than advise poor farmers to buy pesticides - which can be expensive. One trick is to use natural attractants to lure female insects onto the wrong type of host plant to lay their eggs. When the eggs hatch, there is nothing for the young ones to eat and they die.
Finding pest-control methods appropriate for Africa is the aim of research conducted by the International Centre for Insect Physiology and Economy, established in Kenya in 1970.
Ironically, some of the methods the pest center is trying to perfect were prevalent in Africa before chemical pesticides became popular.
For example, these scientists have found that intermixing crops such as sorghum and cowpea in the same field can deter pests. Such intercropping is an old African technique. Large groups of insects that are normally attracted by one crop become confused by the combination. This discourages them from settling in the field, says Wellington Otieno, a research and development manager at the pest research center, who was in Boston recently. His institute is trying to determine why the insects become confused.
The research center is also involved in improving varieties of maize, sorghum, and cowpea that resist certain pests. This resistance isn't completely understood, but researchers know that some lines are less desirable because they are low in the sucrose that insects feed on. Others are covered with long hairs that make it difficult for an insect's mouthpart to penetrate the leaves.
At present farmers working directly with the institute receive free seeds of these resistant strains. Eventually the seed companies and the Ministry of Agriculture will sell them. But ``since we developed it and we are a nonprofit organization ... they cannot make a profit on it,'' Dr. Otieno says. He expects the price to be within the reach of most farmers.
Otieno says the techniques used by the group fall under the broad heading of integrated pest management - a worldwide approach that encourages the coordination of many available pest-control techniques into an economical, ecologically sustainable system. Some use of chemical pesticides, if necessary and affordable, is consistent with the approach.
Integrated pest management is becoming ``universally accepted'' as the only ``rational route'' for pest control, Otieno says. He bases his observation on an internationally attended conference on integrated pest management held in Sturbridge, Mass., last month. Severe ground-water contamination and pests' growing resistance to chemical pesticides are a few of the problems driving the United States toward this ``holistic'' philosophy.
Many farmers in developing countries simply can't afford pesticides. Besides, if not applied properly, they are extremely dangerous, Otieno says.
``Slowly but surely people are beginning to realize we can't rely on pesticides,'' says Allen Steinhauer, chairman of the department of entomology at the University of Maryland and executive director of the Consortium for International Crop Protection. He says scientists have known the value of alternative methods for a long time, but sometimes they are more complex and take more training to apply than chemical ``fixes.'' He thinks that in the long run methods like those studied by the pest center in Kenya are probably less costly than pesticides.
Kenya's pest center has been criticized in the past for having an ivory tower approach. Because the institute conducts ``fairly high-level research, the criticism is that it will take a while to apply,'' says John Gaudet of the Technical Resources Office of the US Agency for International Development. Mr. Gaudet blames African governments in part for not helping to disseminate the research.
The Kenya institute is distributing newsletters and journals to reach farmers and institutions across Africa.
Otieno has obviously been pondering other possible improvements.
``A very well-trained African scientist may get stuck in the corner of a poorly equipped laboratory,'' he says.
Most of all, Otieno is concerned about keeping his researchers in the ``stream of world science.'' The center's scientists need to be able to attend more regional and international meetings, ``so that a researcher in West Africa would know what a researcher in East Africa is doing. Right now you find a lot of duplication because they do not meet, they do not know,'' he says.
Although the center is unusually well supported for an African research institute (it is funded by the World Bank and several other organizations and governments), it has some of the same problems that confront all of African science.
``So many of these things depend on government stability,'' says Dr. Steinhauer of the University of Maryland. ``But there have been some islands of hope, and ICIPE is one.''