Correspondents' Correspondence

...There is some concern, however, that the pests' transplanted adversaries might eventually become troublesome themselves once they are fully established in their new environment...

...Biological pest control, a seemingly simple strategy, is based on the principle of deploying beneficial bugs against those that are destructive...

...One of the long-term objectives of the Institute of Tropical Agriculture is the development of a pest-resistant form of cassava...

...In the cassava program it has the backing of many universities and scientific institutions in Australia, Canada, the United Kingdom, and the United States...

...Headquartered in Ibadan, Nigeria, it receives funding from the Consultative Group on International Agricultural Research, an organization that includes governments, global agencies and private foundations committed to seeking out ways of raising food production in the "hungry bell" of the world...

...Failure of the effort could result in death, famine and suffering of almost inconceivable proportions...

...Fighting Pests with Pests London—A group of worried West African nations have launched a gigantic biological pest-control experiment intended to save the cassava plant, the region's staple crop, from the depredations of insects that are virtually immune to pesticides...

...If all goes according to plan, the problem may well be contained by 1989...

...The harvest was first threatened in the early 1970s, when two insects indigenous to the Americas—the mealybug and the green spider mite—were accidentally introduced into Africa...

...But for the short term, the biological approach is critical...

...The institute in Nigeria is now building a $2.5 million facility capable of producing 50 million predators a month, and several smaller units are currently under construction in Zaire, the Congo and Senegal...

...Food imports have doubled in volume during the course of the past decade and risen five times in value, absorbing 32 per cent of the continent's 1980export earnings, as compared with 10 per cent in 1970...

...It is hoped that they will succeed in reclaiming approximately a million hectares (2.5 million acres) annually...

...Agricultural scientists everywhere are expected to follow the undertaking's progress very closely, for if it succeeds it will help to end a worsening disaster that cost the food-deficient continent an estimated $1.8 billion in losses during 1983 alone...

...About 200 million men, women and children south of the Sahara—to say nothing of additional hundreds of millions in Latin America and the Far East— depend on cassava roots (also called manioc) for better than half of their daily caloric needs...

...After compiling a list of 18 predators that might do the j ob in Africa, specialists in Nigeria, Colombia and Brazil selected a wasp to attack the mealybug and a phytoseiid mite to keep down its green spider counterpart...

...The project is being coordinated by the Institute for Tropical Agriculture...

...Africa as a whole produces something like 48 million tons of the plant annually on 7.4 million hectares (roughly 18.3 million acres) of land...

...Unless its staple can be saved while new strains are being developed, already hungry Africa will almost certainly face a catastrophe unprecedented in modern times...

...A recent paper issued by the institute warns rather chillingly: "Tropical Africa is in the midst of a food crisis...

...Since its establishment in 1967 to study and improve I lie traditional farming systems of the Southern Hemisphere, the institute has trained more than 2,500 specialists representing 80 countries...

...Because of the escalating economic costs, health hazards and environmental side effects associated with toxic chemicals, the technique offers what many investigators regard as an increasingly attractive alternative...

...In 30 out of 35 countries population increases have outstripped food production, and the average African has 10 per cent less to eat [today] than a decade ago...

...All 20 countries affected by the emergency will release these new weapons on the ground and in the air...

...Unfortunately, they thrive on cassava, spreading their range at a rate of 300 miles each year and devastating yields despite vigorous insecticide treatment...

...The joint cassava effort is thus a great deal more than a mere attempt to promote a novel method of pest control.—Thomas Land...

...In the New World natural enemies curb the two troublemakers—hence the recourse to biology...

...It is used as well in animal feed and in producing ethanol...