Grantee News 

The Organic Center Seeks Organic Solutions to Citrus Greening 

March 9, 2015

The UNFI Foundation supports The Organic Center’s research to find organic methods for controlling citrus greening disease, a disease spread by the Asian citrus psyllid that has decimated the citrus industry. The disease has wiped out 90,000 acres of citrus, resulted in the loss of 8,000 jobs, and done $4.5 billion worth of damage to the United States economy. By the year 2020, it is estimated to decrease citrus production by over 65%, and some scientists believe it might result in a total loss of domestic citrus production.

As of yet, there are no cures for citrus greening, and the current tools have limited efficacy. The most commonly used tool is pesticides, especially high doses of a class of pesticides known as neonicotinoids. These pesticides have not been able to eradicate Asian citrus psyllids and they have been causing large-scale bee die-offs. Even at low doses, chronic exposure to neonicotinoids is toxic to bees. The doses used to control citrus greening are so high that they cause acute toxicity. In addition, psyllids are quickly developing resistance to the sprays.

To top it off, the chemical sprays are killing natural predators of the Asian citrus psyllids. This means that immediately following a spray, levels of psyllid populations dip, but then they rebound to levels above what they were before the spray because their natural predators, like lady beetles, are no longer around to keep their populations in check.

To address this, The Organic Center is researching solutions to citrus greening that are holistic and take multiple factors into account so they can continue to be effective in the long run without harming beneficial insects or causing other damage to the growing systems. The UNFI Foundation has funded a study in collaboration with The Organic Center and Dr. Michael Rogers, a professor at the University of Florida, looking at the efficacy of organically approved materials in controlling Asian citrus psyllid populations. There are several organically approved materials marketed for controlling citrus greening, but no one knows how effective they are or in what combinations, spray levels, or frequency they need to be used to achieve maximum efficacy. It is The Organic Center’s hope that these methods will be helpful to organic and conventional growers alike, especially as psyllids become increasingly resistant to synthetic chemical sprays. These results will help provide alternatives to toxic sprays on citrus.

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 Photo courtesy of The Organic Center