Friday, August 17, 2007 Controlling pests: Back to the basics By Henrylito Tacio Regarding Henry
IT ALL started as a contest. Jose Madera decided that his mangosteen farm should go organic. He wasn't quite sure what to expect. "I was told that it would be impossible; my brother was petrified," he admitted.
His brother Jonathan also grows mangosteen but kept using the traditional chemical sprays.
Three months later, the brothers started harvesting. The number of fruits damaged by insects was just about the same in both orchards. In other words, Jose's organic pest-control techniques proved equal to Jonathan's conventional chemical spraying. Jonathan was impressed enough that he has now stopped using insecticides altogether.
In most parts of Asia, including the Philippine, farmers are raising crops without using pesticides.
"Every year, people are killed due to accidental poisoning by agricultural chemicals," said Roy C.
Alimoane, the director of the Davao-based Mindanao Baptist Rural Life Center (MBRLC) Foundation, Inc.
But what is alarming is that most of these chemicals, once they enter the human body, cannot be excreted.
They are accumulated and may even cause slow death.
Five years ago, George Angara, a 43-year old rice farmer, would wake up with an uneasy feeling of nausea and dizziness.
He would also worry for his neighbors who have been encountering similar symptoms of what was diagnosed as pesticide poisoning.
"The shortcomings of pesticides strategies for pest control are well known," observed Dr. Kevin D. Gallagher, former deputy regional coordinator of the pest management in the region funded by the UN Food and Agriculture Organization (FAO).
Aside from high cost, pesticides also facilitate in the resurgence of new pests. For instance, rice brown planthopper outbreaks are caused by pesticide applications that kill the natural enemies of the pests.
Farmers are not the only ones who suffer from health impacts of using pesticides - even consumers themselves. "Pesticide residues in vegetables sold in the public markets are frighteningly high," Alimoane pointed out.
Today, farmers are going back to the basics. In Cordillera region, for instance, farmers are now using the "good guys" against the "bad guys." Actually, the "good guys" are predators (spiders, beetles, bugs, and others), parasites (wasps, some fly species, etc.), and microbial pathogens or diseases that prey on the "bad guys" and keep them in check in natural and agricultural ecosystems.
The "bad guys" are insect pests (diamondback moth, brown planthoppers, black bug, and stem borers, among others) that attack agricultural crops.
Using "good guys" - the farmers' ally in controlling pests of crops without pesticides - is just part of the scheme called integrated pest management (IPM).
Under the IPM philosophy, chemical spraying is resorted to only when it is "extremely necessary" - for instance, during an outbreak.
Cultural methods of pest control are aimed at lessening the sources of pests or at reducing the exposure of plants to infection. Its primary objective is to prevent pest damage, not to destroy an existing and damaging pest population.
Examples of cultural methods are the use of indigenous varieties for planting (they are hardier and relatively more resistant to pests and diseases) and mesh screen (nylon nets), multiple cropping (planting of different crops in the same area), and crop rotation (a practice of following a crop susceptible to a pest by a resistant crop).
Planting of aromatic herbs with the main crops also repel insects. Among the most often used herbs are onion, leek, garlic, oregano, mint, sweet and sacred basil, and marigold.
Rouging also represses pests. This is done by removing diseased plants or plant parts to prevent the spread of microorganisms to uninfected areas.
Good soil preparation also does the trick. "A healthy soil means healthy plants which are relatively more resistant to pests," Alimoane explains. "A soil rich in humus hosts a wide variety of beneficial 'microflora' that trap nematodes and destroy or keep in dormancy disease organisms, thus encouraging beneficial insects."
