When good bugs turn bad

摘要

In 1987, the US declared war on the Russian wheat aphid—a tiny insect that was annihilating harvests, forcing farmers to drench their fields with added chemicals and costing the US millions of dollars each year in pesticides and lost exports. Entomologists scoured the aphid's natural habitats from France to Uzbekistan for predators and parasites. When they found them, they bred and released them in numbers to rival a biblical plague. Aphid flies, flower flies, seven species of parasitic wasps and 12 of ladybirds (called ladybugs in the US)—24 different organisms in all were enlisted in a 10-year campaign that was so successful in some regions that farmers were able to put aside their anti-wheat-aphid chemicals.