Crops That Can Send an SOS : Plant ‘communication’ may be a way to win the war against bugs
The image of a crop duster strafing the green fields of the Central Valley symbolizes the prevailing approach to pest prevention in agriculture. Surprisingly, however, given our seeming ability to outgun the little varmints, they are beginning to win the war. In recent years, a variety of insects have been shrugging off pesticides. The larvae of Washington state’s brown and gray coddling moths, for instance, are burrowing into apples, while some beetles in Colorado are gobbling potatoes.
Due to genetic mutations, many types of insects have developed immunities to the poisonous mists humans rain on them. And if their rate of genetic immunization continues, pests might become resistant to insecticides faster than chemical companies can concoct new poisons, scientists say.
It’s premature, however, to give the bugs our land deeds. Research by American and European scholars suggests that the problem can be solved through a new, environmentally savvy kind of agricultural stewardship. The key, they say, lies in learning to view agricultural fields not as enemy-occupied territory to be targeted but as ecosystems to be managed. It’s based on an understanding of the sophisticated strategies that some plants and insects marshal in their own defense.
In 1983 researchers suggested that pest-damaged trees might be sending warnings to other trees nearby, telling them to arm themselves against attack. Late-night TV show jokes ensued, and research nearly ground to a halt. But the green researchers are back. As Marcel Dicke of the Netherlands’ Agricultural University put it: “We need to breed for loudly crying plants rather than for deaf and dumb plants.”
At the forefront of this research are scientists like Jim Tumlinson, whose work for the U.S. Agricultural Department has shown that some species of maize and cotton being attacked by parasites produce an SOS scent that attracts wasps that eat the pests. Farmers can reduce toxic pesticide use by cultivating these species, although some are slower-growing and, in food crops, less flavorful.
In terms of health, the need to move away from traditional pesticides has been apparent for decades, and the evidence keeps mounting. In September, a California Public Health Foundation study showed that several pesticides once considered safe may cause cancer and birth defects. Partly because of the new research, Congress passed a sweeping pesticide reform bill earlier this year that requires lower levels.
Some farmers of course will balk at the notion of defending their crops with biologically engineered bacteria and cotton that can cry for help. But as the costs of pesticides soar and the lists of legal pesticides shrink, it’s important for farmers to spend more time with Mother Nature, not only for her ecological wisdom but for their economic prosperity.
