BRAZIL HARVESTS ABOUT 2.2 million tons of tomatoes a year and exports them around the world. Unfortunately, it must spray about 70% of the crop with chemical pesticides to hold larvae of the voracious South American tomato moth at bay. Even then, bugs sheltered in leaves can survive the dousing and destroy the crop.
Cornell University scientists believe they can eliminate the need for 90% of that spraying. They've identified and synthesized a pheromone--a natural sex attractant--secreted by the female moth. Placing it in traps in recent tests in Brazil, they succeeded in capturing thousands of male moths in a single night. "Normally, we would be happy if we trapped a few hundred," says Cornell chemistry professor Jerrold Meinwald, who heads an international team of researchers.
The first hurdle was obtaining the natural pheromone from female moths, which release it for only 30 minutes during the day. Traditional gas chromatography and mass spectroscopy provided the first glimpse of the molecule's unusual structure. Scientists fine-tuned their understanding through a new technique that involves putting the molecule through chemical transformations. The team then synthesized the pheromone and applied for a patent. Meinwald says the new mode of chemical analysis could help researchers to characterize pheromones from other pests.