Pesticide Use and Abuse in Irrigated Areas

Pesticides are used widely to control insects, weeds and fungi, that might otherwise destroy a large part of the world's food crops. They are also used in many countries to control insect vectors of human diseases such as malaria.

It has been estimated that at least three million cases of pesticide poisoning occur worldwide each year, with 220,000 deaths. The majority of these poisonings occur in developing countries where less protection against exposure is applied, knowledge of health risks and safe use is limited and harmful pesticides are easily accessible. Despite the magnitude of the problem of pesticide poisoning, there have been very few analytical studies in developing countries to identify the risk factors.

The dangers of pesticide use to human health can be summarized as:

  • Acute poisoning caused by intentional, occupational or accidental exposure
  • Adverse health effects caused by long-term (mainly occupational) exposure

In Sri Lanka, pesticide poisoning is often identified by farmers and health workers as the primary health concern in irrigated areas. The high use of pesticides in irrigation schemes makes the study of pesticide-related health problems especially relevant to irrigation communities.

IWMI has done studies to analyze the reasons for the high number of pesticide poisoning cases and to explore ways of controlling the problem through changes in agricultural practices and community involvement. More recently, research has focused on risk factors for pesticide poisoning and on the impact that a shift towards Integrated Pest Management (IPM) will have on human health.

For reprints of specific journal articles please write to Ms. Himani Elangasinghe at

Now available:

Peiris-John RJ, Ruberu DK, Wickremasinghe AR, Smit LAM, van der Hoek W (2002) Effects of occupational exposure to organophosphate pesticides on nerve and neuromuscular function. International Journal of Occupational and Environmental Medicine 44: 352-357

Michael Eddleston, Lakshman Karalliedde, Nick Buckley, Ravindra Fernando, Gerald Hutchinson, Geoff Isbister, Flemming Konradsen, Douglas Murray, Juan Carlos Piola, Nimal Senanayake, Rezvi Sheriff, Surjit Singh, S.B. Siwach, Lidwien Smit (2002)
Pesticide poisoning in the developing world—a minimum pesticides list. Public Health, The Lancet, Vol.360, October 12, 2002

Flemming Konradsen, Wim van der Hoek, Donald C. Cole, Gerald Hutchinson, Hubert Daisley, Surjit Singh, Michael Eddleston (2003) Reducing acute poisoning in developing countries—options for restricting the availability of pesticides. Elsevier, Toxicology, 192 (2003) 249-261

Van der Hoek W, Konradsen F, Atukorale K, Wanigadeva T (1998) Pesticide poisoning A major health problem in Sri Lanka. Social Science and Medicine, 46: 495-504.

Feenstra S, Jabbar A, Masih R, Jehangir WA. (2000)
Health Hazards of Pesticides in Pakistan. IWMI Pakistan Report no.100. IWMI and Pakistan Agricultural Research Council.

Smit LAM (editor). (2002)
Pesticides: Health impacts and
alternatives. Proceedings of a workshop held in Colombo, 24 January 2002.
Working Paper 45. Colombo, Sri Lanka: International Water Management Institute. (Available online)

  • Economic & environmental impact assessment of urban and peri-urban agriculture
    Identifying and quantifying off-site effects of intensive urban peri-urban agriculture, including pesticide use. more information>>
  • Occupational pesticide exposure
    Determining the health effects on farmers of regular exposure to pesticides. more information>>
  • Acute pesticide poisoning in rural communities
    Understanding the leading causes of acute pesticide poisoning in Sri Lanka and developing recommendations for prevention. more information>>

How can cases of acute pesticide poisoning be reduced in Sri Lanka's rural communities?

  • Hazardous practices when spraying pesticides were found to be due to the impossibility of applying recommended protective measures under the local conditions, more than to lack of knowledge.
  • Current emphasis on programs that promote the safe use of pesticides through education and training of farmers will be ineffective in Sri Lanka because knowledge is already high and because most poisoning cases are intentional.
  • Enforcement of legislation to restrict availability of the most hazardous pesticides would result in an immediate health benefit.
  • Improved agricultural extension services to promote alternative non-chemical methods of pest control is the best long-term strategy for preventing acute pesticide poisoning.

The PAN Pesticides Database brings together a diverse array of current toxicity and regulatory information on pesticides.

Click here for more on-line resources

last updated 20 September 2003

Findings and recommendations
Links to on-line resources

Seminar on Pesticides in Sri Lanka: Health Impacts and Alternatives

IWMI held a seminar on January 24, 2002 in Colombo to present recent research findings on health impacts of pesticides in Sri Lanka and to discuss alternatives to pesticides such as Integrated Pest Management (IPM) and a Minimum Pesticides List.

The workshop proceedings are available as IWMI Working Paper 45. The paper includes a resource handbook for Sri Lanka on health impacts of pesticides and alternatives by listing names of relevant institutes, addresses and annotated references.

For more information on the seminar and resource handbook please contact Lidwien Smit at

Farmer applying pesticide to rice plants, Sri Lanka.


Integrated pest management (IPM) is an ecological approach to plant protection that was identified as a key element of sustainable agricultural development in Agenda 21 - the action plan developed by the United Nations Conference on Environment and Development, convened in Rio de Janeiro in 1992.

IPM makes full use of natural and cultural control processes and methods, including host resistance and biological control.
It also involves a wide range of other practices aimed at growing a healthy crop.
Farmers learn about the ecology of their fields and, as a result, they make and implement decisions that are safe, productive and sustainable.
IPM uses chemical pesticides only where and when the above measures fail to keep pests below damaging levels.
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