Getting off the pesticide treadmill



Getting off the pesticide treadmill



BARBARA DINHAM

describes how partnerships to implement
integrated pest management boost yields,
save money and protect the environment





crop dusting

Governments, agricultural corporations and research institutes often call for increases in food production in the most productive areas, and promote agriculture based on monocultures of high-yielding varieties of crops which require large amounts of pesticides. Yet insects can quickly develop resistance to the chemicals. Pests then tend to increase rapidly, encouraging even greater pesticide use, which again is likely to be ineffective.

A growing number of scientists, researchers and practitioners reject this approach both because it causes environmental problems and because it cannot maintain yields. The chemical inputs threaten biodiversity and destroy the pests' natural enemies while farmers' knowledge, practices and observational skills are undermined. Dr. Jeff Waage, Director of the International Institute of Biological Control, has said: 'If we look at our serious pest problems around the world today, a sizeable proportion of them have been introduced or made substantially worse by pesticide use: rice planthopper, cotton bollworm and whitefly, diamondback moth on cabbage, and many more in virtually all the major crop systems including vegetables, cereals, cotton and plantation crops. These induced pest problems, in turn, can be traced to the elimination of local natural enemies by insecticide use.'

Meanwhile the scale of chemical pesticide use has brought health problems to agricultural workers, small farmers and rural communities: the World Health Organization estimates that these cause 20,000 deaths a year and millions of cases of poisoning, mainly in developing countries.

For more than 30 years, the concept of integrated pest management (IPM) - which combines a range of controls, including conserving natural predators, using pest resistant crop varieties, intercropping and rotation, with pesticides used only selectively and in small quantities - has struggled to gain ground against conventional agricultural ideology and practices. But it is now increasingly challenging the methods of high-input agriculture and developing solid lessons that cannot be ignored.

Many of the scientists and researchers promoting IPM argue that all chemical pesticide use should be discouraged in developing countries. The Field Programme Circular (December 1992) of the Food and Agriculture Organization of the United Nations (FAO) said that 'suitable pest-control methods should be used in an integrated manner and pesticides should be used on an as-needed basis only, and as a last resort component of an IPM strategy'. It encouraged consideration of a system of non-chemical pest methodologies before decisions were taken to use pesticides.



A success story

Much attention in implementing IPM has focused on rice, largely because of its central role in food security in Asia, where 90 per cent of the world's crop of the cereal is grown and where half the Earth's population eats several bowls a day. One of the most quoted success stories is IPM's triumph against an Indonesian infestation of brown rice-hopper. The insect was resistant to pesticides, natural predators had been wiped out, and the narrow genetic base of the high-yielding rice variety could offer no resistance to attack. Pesticides were sprayed up to 50 times a season without having any impact on the resistant insects, which practically decimated the country's harvests in the mid-1980s. The Government backed an IPM approach and banned 56 insecticides from being used on rice. Rice yields rose by 13 per cent while pesticide use dropped by 60 per cent in just five years after the approach was widely introduced: in the first two years alone the Government saved $120 million that would otherwise have been spent on subsidizing the chemicals.

The Indonesian programme - which was supported by the FAO regional IPM programme in South and Southeast Asia - was based on farmer field schools: Dr. Peter Kenmore, its Director, had long been convinced that the IPM concept would fail unless farmers participated in understanding and applying solutions. The training takes place in farmers' fields: both trainers and farmers are taught how to identify pests and their predators, to understand when a pest will cause economic damage, and to learn how much a plant can fight back. Two hundred thousand farmers were trained between 1985 and 1990 - cutting their average pesticide use to less than one application per season as a result. The Government's full backing for the programme was a further crucial element in the Indonesian success: high-level policy support is essential if IPM is to be adopted on a country-wide basis.



Wide-angle approach

Some critics say that IPM is too focused on biological controls, but insect pests provide one of a number of initial entry points to farmers' concerns. Dr. Waage says: 'IPM programmes on rice in Asia, which were stimulated by insect pest problems, have as their strategy three elements: grow a healthy crop; inspect fields regularly; and conserve natural enemies.' IPM has moved beyond its roots in insect control to examine the whole plant-pest ecology. It takes account of the entire crop cycle and of management of weeds, diseases and soil in a way that both produces more food and is ecologically and economically sustainable.

Kevin Gallagher, an agronomist who has worked on the FAO IPM programme and is now helping to identify high production organic agricultural methods in Asia, points out that farmers are introducing their own innovations beyond simply dealing with insect pests: 'Ducks are being reared for weed control in Japan, Korea, Viet Nam and Thailand,' he says. 'Live mulches are being tested in Thailand and Laos... rice and mung bean are broadcast simultaneously so that the mung bean becomes a mulch while the rice is established and the field is flooded.'



industry

Healthy yields, healthy savings

The success of the farmer field schools in Asia demonstrates that IPM training can be effective when it is not simply packaged as part of a top-down extension message. Between 1980 and 1993 about 18,000 extension agents and 500,000 farmers were trained in Bangladesh, China, India, Indonesia, Malaysia, the Philippines, Sri Lanka, Thailand and Viet Nam. In 1994, a report of the programme showed that IPM-trained farmers saved an average of $10 per hectare every season, while maintaining or increasing their yields.

Yet Asian rice producers still use about 13 per cent of the world's pesticides despite IPM's success in the region. A World Bank study confirms how subsidies and development policies have encouraged excessive pesticide use. And a new FAO report on rice and the environment estimates that pesticide use could be reduced by 50 per cent or more without compromising crop yields and while maintaining or improving net returns to the farmer: regional savings could amount to $1 billion per year.

IPM recognizes that farmers' knowledge - and not just the technology - is the key to success. It thus takes its place in a broad school of sustainable approaches, ranging from organic agriculture to low external-input practices. These are not so much 'low' input approaches, but stress local inputs - of knowledge, recycled nutrient materials, natural predators - above dependence on chemicals or other external factors. Recent lessons confirm that the crucial dimension is a participatory approach, which works with farmers, develops partnerships between them and the research community, and is supported by a sympathetic policy environment.


Barbara Dinham is the International Projects Officer at the Pesticides Trust, a non-governmental organization which addresses the health and environmental problems of pesticides, and promotes sustainable agricultural options.


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