Science - February 17, 2005

Botanical pesticides help sick farmers

Synthetic pesticides on Sumatra and nearby islands are causing health problems among the farmers that use them. There are healthier and effective alternatives, botanical pesticides, but people have forgotten about them, according to PhD researcher Wiratno, of the sub-department of Toxicology.

Wiratno examined the health of farmers on the island of Bangka, to the east of Sumatra. The farmers use large amounts of synthetic pesticides to kill insects that destroy their black pepper crops. The big problem is the beetles that eat the plants: the insecticides used against them contain very toxic organic phosphorus compounds.
Analysis of blood and urine samples indicated that the farmers have substantial amounts of the toxins in their bodies. Wiratno warns that this can lead to, for example, reproductive problems and cancer. The short-term health effects are also evident in the area where he is doing his research: ‘The farmers often complain of headaches and vomit frequently. But they regard this as ‘normal’. They have become used to these symptoms and do nothing about them.’
The problem is the toxic pesticides, but also the fact that the farmers do not observe the correct safety procedures when applying the pesticides, Wiratno discovered. They do not use protective clothing, and therefore the pesticides come in contact with their skin and are absorbed into their bodies.
According to Wiratno the best solution is to go over to using botanical pesticides. He made a survey of the plants on Sumatra that could be used, and advises the use of for example the ‘Tuba root’, which contains rotenone, a substance that has pesticide properties. This poison used to be used for arrow tips. Wiratno also mentions neem oil as a possibility, which contains the active ingredient azadirachtin.
The problem is that traditional plants used as pesticides have become forgotten in Indonesia, says Wiratno. ‘It has become very easy to get synthetic pesticides, and they are cheap. But this is a problem; we must convince farmers to go back to their old methods.’ Under supervision from Dr Tinka Murk of Toxicology and together with a number of researchers including Dr Paul van den Brink of Alterra and Dr Jan Kammenga of the Laboratory of Nematology, Wiratno will now concentrate on further investigating traditional botanical pesticides. He will conduct bioassays to assess the toxicity and also test new formulas. / HB