"Cassava farmers are among the world's poorest, and few can afford to control pests with chemicals. Pesticides also worsen pest problems by killing off friendly insects that prey on or parasitize cassava pests", reported Anthony Bellotti, a CIAT entomologist, at a symposium held in Washington D.C., October 21, "Cutting- Edge Science for Earth Friendly Farming" sponsored by the Public Awareness Association of the CGIAR and chaired by Per Pinstrup- Andersen, Director General of IFPRI.

The symposium gave scientists from six international centers; International Rice Research Institute (IRRI), International Institute for Tropical Agriculture (IITA), Centro Internacional de Agricultura Tropical (CIAT), International Crops Research Institute (ICRISAT), Centro Internacional de la Papa (CIP), and the Asian Vegetable Research and Development Center (AVRDC), the opportunity to share innovative research findings in integrated pest management.

IRRI Study Finds Hazards For Farmers Households

Ken Fischer of IRRI reported on a major new study on the health effects of pesticide use on rice farmers. Researchers at IRRI, headed by agricultural economist Prabhu Pingali, studied 152 rice farmers in three Philippine provinces for a two- year period. The study has wide implications for developing countries where there is little education about appropriate pesticide use. It found that inadequate storage, unsafe handling practices, short intervals between pesticide spraying, and inefficient sprayer maintenance create enormous exposure to chemicals by farmers and their households. More training and information campaigns on proper pesticide management are needed to lower health risks.

IITA scientist Hans Herren introduced a new method to control locusts and grasshoppers using a natural fungal spray that does not harm other organisms. The formulation is prepared with inexpensive ingredients that are readily available in most parts of Africa and developing nations elsewhere. When they are infected by the fungal preparation, locusts and grasshoppers die within four to ten days. "The world has urgently needed an effective weapon against these insects said Herren, director of IITA's Plant Health Management Division. "Until now, dieldrin - - an insecticide so environmentally destructive, it has been banned in many countries - - has been the method of control. Less potent insecticides have not been able to control these insects adequately, and therefore have required more frequent application, creating more environmental risk."

ICRISAT reported that a variety of pearl millet has retained resistance to the deadly fungus known as downy mildew for more than 11 years. Downy mildew is a fungal disease that grossly alters plants by destroying the grain. Since 1968 it has been responsible for the loss of a crop fundamental to the survival of the population in the driest parts of India. Don Blyth, head of the Cereals Program, reported that ICRISAT has focused on raising the pearl millet yields while maintaining resistance to downy mildew. As a result, people in the most marginal areas of the semi- arid tropics have had an estimated $54 million worth of extra food each year. He said the disease has been defeated, but vital research is continuing to find the genes that can provide permanent resistance to downy mildew, even in a hybrid.

Avoiding Another Irish Potato Famine

Disturbing news was given by Hubert Zandstra, Director General of CIP, new outbreaks of a form of late blight fungus, the disease that caused the 19th century Irish potato famine. According to Zandstra, the disease is a major threat to potato producers in both the developing and industrialized world. Experts believe that the disease spread from Mexico to Europe in the late 1970s, and was then exported through the sale of infected potato seed. He stated that emergency breeding efforts are needed, which would include researchers from all affected countries and private industry. CIP has developed several breeding lines that have proved to be resistant in Mexico, where late blight populations are most diverse.