Locust Control in Madagascar
July 10, 2000

In recent years, the island of Madagascar has experienced a major locust plague. In 1997, the government called for international aid to fund locust control operations. A report in the most recent Pesticides News, the quarterly publication of PAN UK, looks at the impacts of decisions to aerial-spray insecticides over large parts of the country and at the potentially devastating environmental consequences on an island renowned for its biodiversity. There has been no systematic monitoring of the human health impacts of the spraying, or assessment of whether locusts have caused enough damage to affect food supplies in Madagascar.

Madagascar lies off the east coast of Africa in the Indian Ocean. Nearly 78% of the 15 million residents are farmers living in rural areas; per capita income is one of the lowest in the world.

Locust control operations have been oriented entirely around large-scale application of synthetic chemical insecticides. From 1997 to 1999, more than US$35 million was spent on pesticides applied from the air and on the ground. The pesticide most commonly used was fipronil, a relatively new active ingredient not fully tested for use in Madagascar. Fipronil has been classified by the U.S. Environmental Protection Agency as a possible human carcinogen.

A survey of 100 people in one spray area found that 60% showed symptoms of pesticide poisoning. Of a further 38 people tested, 80% showed reduction in cholinesterase activity due to exposure to organophosphate or carbamate insecticides.

The European Union and Cóoperation Français were the primary donors funding control operations; the World Bank provided some initial funding but withdrew support in 1998 because of concerns over the pesticides used. As the Madagascar locust campaign continued, some donors questioned the strategies employed. Their investigations suggest the scale of food losses may be exaggerated and that the volume of spray treatment could be reduced. But in spite of concerns, the UN Food and Agriculture Organization (FAO) drew up a budget in 1999 for a further US$17.6 million to continue the operations.

The UK Department for International Development (DFID) was one of the few donors, with the German aid agency GTZ, to provide funds for an assessment of the environmental effects of the widespread spraying program. The study, carried out by UK-based Natural Resources Institute (NRI), became the first in the world to monitor the environmental impacts of an emergency locust control program.

As a result of their investigations, NRI researchers found that fipronil had a serious impact on termite populations in sprayed areas. Six months after spraying, few, if any, healthy colonies survived in termite mounds within the barrier spray areas. Ecological implications could be devastating since termites play a crucial role not only in nutrient cycling, soil structure and water infiltration, but also as a food source for animals higher on the food chain. The NRI study also found evidence of adverse impacts of fipronil on other non-target insects including bees and possibly some lizards and birds.

In May 1998, a U.S. Agency for International Development (USAID) team spent two weeks in the country studying two areas of high locust concentration. The team found that crop losses from locusts in the area were substantially below anticipated levels. In one area, farmers interviewed told of losses in corn and rice of more than 50%. However, when asked how they would deal with the loss, 82% responded that they had planted cassava as a back up crop, which they could either eat or sell to buy other food.

Farmers in Madagascar have developed a range of responses to these outbreaks, and it appears that the outbreaks of the last few years have not had a significant impact on food supplies. It is widely understood by locust experts that preventive approaches, including monitoring and an early response system, to locust outbreaks are superior to “emergency” action.

Past experience points to the dangers of ignoring a precautionary approach. Years of spraying locust outbreaks in the Sahel with the environmentally-persistent organochlorine dieldrin had unforeseen consequences. Residues of this deadly pesticide can still be found throughout the global environment, in the food chain and even in human bodies.

The report in Pesticides News looks in detail at the pressures that led to a trail of poor decision-making, which may have caused irreversible damage to this unique tropical ecosystem.

Source: “Poisoning an Island? Locust control in Madagascar,” by Barbara Dinham, Pesticides News 48, June 2000. The full report can be viewed at http://www.pan-uk.org/pestnews/pn48/pn48p3.htm. A fact sheet on fipronil is also on the Web site, and an expanded briefing will be available shortly.

Contact: Pesticide Action Network UK, Eurolink Centre, 49 Effra Road, London SW2 1BZ, UK; phone (44-020) 7274 8895; fax (44-020) 7274 9084; email admin@pan-uk.org; http://www.pan-uk.org.

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