The Asian citrus psyllid, which can spread huanglongbing, is the target of research at the University of Florida. Researchers are testing a fungus for its ability to kill the pest in a Vero Beach commercial grove. ( File photo )

Research at the University of Florida to eradicate citrus greening disease isn’t focused solely on helping trees fight the disease. Researchers also are attacking the source: the Asian citrus psyllid that spreads the disease, also known as huanglongbing (HLB).

Efforts at the university’s Institute of Food and Agricultural Sciences and the Florida Research Center for Agricultural Sustainability are testing the ability of a fungus to kill the psyllids in a Vero Beach, Fla., grove.

The fungus, Isaria fumosorosea, kills and changes the feeding behavior of the pest, according to a news release.

“Applied biological control is an integral and sustainable component of managing all insect pests in citrus groves,” Ronald Cave, director of the institute’s Indian River Research and Education Center, near Fort Pierce, said in the release.

Lance Osborne, a University of Florida entomology professor, discovered the fungus attacking mealybugs in a greenhouse in the mid-1980s, according to the release.

Pasco Avery, a biological scientist at the Indian River center, has worked on the fungus research for years, publishing findings in the journals “Insects,” “Biocontrol Science and Technology,” and “Florida Entomologist.”

“The fungus is not a panacea, but it is expected to greatly reduce the problem we have in managing the psyllid populations,” Avery said in the release. “The fungus kills the psyllid but is compatible with beneficial insects like lady beetles, lacewings and parasitic wasps, which also control the psyllid.”

The research has moved from the lab and into the commercial grove in Vero Beach. Avery is working with Bob Adair, executive director at the Florida Research Center for Agricultural Sustainability, and they conducted the first field spray trial in mid-June, according to the release.

The trial confirmed what Avery found in the lab: the fungus is effective in suppressing psyllids for up to two weeks.

Another trial is scheduled for September.

“What we found with this first experiment was that the fungus was as effective as the active ingredient of the insecticide spinosad,” Adair said in the release. “We tested the fungus for psyllid control, the effect on beneficial insects and resistance management. Now we need to conduct more tests to determine its effectiveness on a wider scale and time range.”

Avery said the fungus was effective in suppressing the psyllid population and that it lasted for up to 14 days after application. The first field trial was conducted to confirm what the scientists had determined in the laboratory. A second field trial is scheduled for September, to gather more data. For the second field trial, both sides of the trees in the same grove will be sprayed with fungus added to the horticultural oil, said Avery.

“What we found with this first experiment was that the fungus was as effective as the active ingredient of the insecticide spinosad,” said Adair. “We tested the fungus for psyllid control, the effect on beneficial insects and resistance management. Now we need to conduct more tests to determine its effectiveness on a wider scale and time range.”

 
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