Ten years ago, a bacterial disease began to eat away at the Florida citrus crop. It's called huanglongbing, or citrus greening, and it causes misshapen, bitter green fruits and, eventually, dead trees. Since 2005, the infection is estimated to have caused billions of dollars in damage. And the microbe did all that damage with the unwitting help of a tiny winged insect, the citrus psyllid, which spreads the bacterium as it feeds. But now researchers at the USDA and the University of Florida have come up with a pesticide-free way to battle the insect: by disrupting its ability to find a mate.
When male psyllids are looking for love, they beat their wings, sending vibrations along a tree's branches. <<male psyllid call>> Nearby females pick up that signal and send back one of their own, <<female psyllid call>> which tells males to come hither.
The researchers eavesdropped on that duet with a microphone, rigged to an electronic microcontroller. And when the controller identified a male's call, it sent out a decoy female response <<decoy call>>--more quickly than real females could respond. <<female psyllid call>> That imposter's call actually lured males to the device, where instead of a mate they found flypaper. The researchers presented the results at a meeting of the Acoustical Society of America, in Jacksonville, Florida. [Richard Mankin and Barukh Rohde, Use of vibrational duetting mimics to trap and disrupt mating of the Asian citrus psyllid, a devastating pest in Florida groves]
The technique isn't ready for the limelight just yet. For one, though the decoy call does fool the bugs, they’re still adept at avoiding the flypaper. But the researchers say this sort of "signal jamming" interference might be able to disrupt the insects' ability to find a mate, cutting overall numbers of the pest. A similar technique has worked in vineyards--and if it works in orange groves, it could help citrus growers get out of this squeeze.
—Christopher Intagliata
