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Scientists Using Fungus to Manage Asian Citrus Psyllid


by MATT NORMAN

Could a fungus be the answer to an invasive insect that is attacking Florida’s $8.63 billion citrus industry? On the surface this sounds strange, but scientists at the University of Florida think that one fungus in particular can help fight the Asian citrus psyllid, and help improve the future for citrus growers in our state.

The Asian citrus psyllid is an invasive insect that is threatening citrus groves throughout Florida. Because it is not indigenous to Florida, its natural enemies — the things that might naturally control its population — aren’t here. The result is a growing population that poses an ever-increasing threat. With no natural enemies in our areas, citrus growers have to use other means to fight these bugs. Historically this meant pesticides. While this may be effective in fighting this destructive insect, it can also threaten some beneficial insects.

This is where the University of Florida and the Isaria fumosorosea fungus come in. This potentially beneficial fungus was first discovered by Dr. Lance Osborne, a professor of entomology at the University of Florida. In the mid-1980s, Dr. Osborn found this fungus to be attacking mealybugs in a greenhouse. Fast-forward to 2018 and UF scientists are finding that this same fungus may hold hope for fighting this current threat.

From a greenhouse in the mid-1980s to the acres and acres of citrus trees growing throughout Florida today, the conditions in which scientists can study the impact of insects on citrus trees have changed dramatically. Dr. Pasco Avery, a biological scientist at the University of Florida, has tested this fungus against psyllids in a laboratory setting. By his own admission, this fungus is not a cure-all for the problem. Still, he believes it promises to have a significant impact on the problem. According to Dr. Avery, the fungus kills the psyllid without posing a threat to “beneficial insects,” which he says help control the psyllid.

Dr. Avery’s next step was to test the fungus in conjunction with horticultural oils that have long been used in the citrus industry. Would this fungus enhance the current techniques? Would the fungus even work when used with these oils? To answer these questions, Dr. Avery joined forces with Bob Adair, executive director at the Florida Research Center for Agricultural Sustainability in Vero Beach. Testing the combination of the fungus and the oils found that it not only killed the insects, but also did so with more efficiency, according to Dr. Avery.

Would these exciting laboratory results translate into real world success? To determine this Avery and Adair took their testing to the field. In mid-June approximately one acre of trees was sprayed with the combination of fungus and horticultural oils. The combination was found to have effectiveness similar to the insecticide spinosad, according to Adair. In the coming months Avery and Adair plan to run similar tests on a wider area to see if this new strategy can bring hope in fighting the psyllid population in Florida citrus groves.