Biological Pest Control

Farmers and agricultural institutions should use biological pest control methods on food crops, an Australian crop scientist said. Dr Paul Ferrar said besides being cheaper than chemicals, they were also less hazardous as the crops would be chemical-free. Biological control refers to the use of natural enemies of organisms to bring them down to control. Pest organisms are anything that affects human foods.

"Until now, chemicals have been seen as the easy solution to pests and weeds, but there are other safer means of pest control, including the use of natural enemies of the pest or weed," said Ferrar who is the research programme co-ordinator for crop sciences at the Australian Centre for International Agricultural Research (ACIAR).

"Chemical fertilizers will always be needed, but we are aiming at a combination of the least possible use of chemicals and greater use of non-chemical methods. Pests and weeds sometimes spread to new areas without the natural enemies that kept them in check in their home range. At the same time, the monoculture of crops may suit the pest better than its enemies and natural control will then fail. Development also increases the chances of pests spreading since it encourages diversification and increases trade in agriculture products."

Recent decades have seen pests becoming stronger as pesticides have killed off their enemies which control them. In some cases, the biological agents alone may solve a pest problem fully. In other cases, the use of several techniques in combination including biological control is needed. Ferrar said biological control was being practiced very widely throughout the world, except in some of the smaller countries. "For instance, in Sri Lanka, it was used to solve the problem of salvinia, touted as one of the world's worst water-weeds because it can double its size every two days. It can choke lakes, reservoirs, canals and rice crops in Asia, Africa, Australia and the Pacific."

Ferrar said the advantage of biological control was its permanency. Therefore, there would not be any need to spray costly and environmental-polluting herbicides. The environmental benefits from biological control includes the preservation of indigenous vegetation through the control of smothering weeds. This will help to preserve general biodiversity, including plants of possible future economic importance, and can also act as a reservoir for beneficial insects that attack pests in crops. "Less spraying of pests can result in less contamination of food by chemical residues (especially important for food destined for export), and less contamination of soil and water supplies," Ferrar said.

Control of weeds in water or along banks of watercourses is important for livestock as well as for transport. Ferrar also said that there would be reduced medical costs from fewer cases of pesticide poisoning.

David Orr, Steve Bambara, and James Bake, "BIOLOGICAL PEST CONTROL: AN INTRODUCTION" Biological Control Information Centre

Dr. L. T. Kok, Ms. Victoria T. Kok "Biological Control for the Public" Virginia Tech's Entomology