Natural Chemical Found in Avocados Kills
April 2, 1997
A natural chemical already present in
some types of avocados kills the Caribbean fruit fly. Thats the word from
scientists with USDAs Agricultural
Research Service who were the first to discover that the chemical--called
estragole--is toxic to the pests.
The ARS scientists found estragole in
varying concentrations in the leaves of 14 varieties of Mexican avocados. But
their tests turned up none of the chemical in seven Guatemalan and 13 West
Indian types of avocados. Estragole is not harmful to humans.
The next step, the scientists say, is to find a way to manipulate the gene
behind estragole to give plants such as fresh citrus natural resistance to the
Caribbean fruit fly and possibly other insect pests.
Fresh citrus shipped to consumers in Japan, Thailand, California, Texas,
Bermuda, and Hawaii must be certified free of the Caribbean fruit fly. The
citrus industry relies heavily on pest-free certification for exporting.
Farmers have met these certification requirements by aerially spraying
groves with malathion bait spray every 7 to 10 days during harvest. But
environmental and health concerns have been raised about malathion, and the
industry is looking for a replacement for the chemical.
Scientific contact: Michael Hennessey, USDA-ARS,
Research Laboratory, Miami, Fla., phone (305) 238-9321,