Helping citrus tough it out.

Helping citrus tough it out

Immature citrus peels shield against fruit fly attack--but only to a point. For a while, oils in the peels kill fruit fly eggs and larvae; the toughness of these peels also discourages fly attack. However, as it ripens, the peel softens and its oil content diminishes--signaling the flies to come and feast.

Now scientists at the Agriculture Department's Insect Attractants, Behavior and Basic Biology Lab in Gainesville, Fla., report laboratory tests showing a partial solution: spraying fruit with gibberellic acid, a natural plant hormone, before the fruit turns from green to its ripe color. This, they say, maintains the tough peel--and fly resistance--in ripening fruit.