| Food chain - Number 19 - November 1996 |
CONTROL OF MALARIA WITH MARIGOLD
In many countries malaria is increasing with a growing resistance to drugs that control the disease and the conventional control measures involving insecticides is cause for environmental concern. Researchers at the Institute of Nuclear Medicine and Allied Science (INMAS) in India have developed an ecologically friendly, biodegradable insecticide from marigold flowers which contains compounds against the larvae of not only Anopheles species but also Cutex the agent of Japanese encephalitis.
The insecticide is made by crushing marigold petals and roots in alcohol. As the alcohol evaporates it yields a yellow extract containing alphateriophene and erythrosin-3. The agents are only active against larvae in the presence of sunlight. Trials have shown a 20 per cent mortality in four days for Anopheles and 100 per cent activity against Culex in three days. The researchers have studied the mechanism of control and claim the biodegradable extract does not pose a health hazard to people. With the increasing trend against the use of toxic, non biodegradable chemicals, work of this nature requires greater attention and we believe offers considerable potential for developing countries - many of which have a still untapped pool of big-diversity.