citrus greening

Studying Citrus Greening with an Integrated Approach

Daniel CooperCitrus Greening, Diseases, HLB Management, Industry News Release, Psyllids, Research

While citrus growers continue to look for best management approaches to deal with the deadly greening disease, scientists will take an integrated look at how to protect young trees by using existing tools growers can use.

Five scientists from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) will compare insect management tools, including insect-proof netting. Researchers also will study reflective mulch, kaolin clay and chemical-based insect pest management. Kaolin clay is a powdery white compound used to conceal citrus trees from psyllids by confusing their visual sensory system.

Citrus tree infected with citrus greening

“All of these tools are aimed at insect management, but it is unclear how they influence other aspects of grove care, like plant growth rates or water use,” said Lauren Diepenbrock, a UF/IFAS assistant professor of entomology and research project leader.

UF/IFAS researchers have earned a $665,471 U.S. Department of Agriculture (USDA) grant. The grant draws funding from several sources, including the National Institute of Food and Agriculture — an arm of the USDA — and from the U.S. Environmental Protection Agency, the Florida Department of Agriculture and Consumer Services and industry groups.

With the funds, they plan to study citrus greening control methods from an integrated perspective.

When they complete their research, the UF/IFAS scientists hope to develop new recommendations for existing tools that growers can use to fight citrus greening, also known as huanglongbing (HLB).

Until now, researchers have evaluated citrus greening prevention methods by studying how they affected one aspect of production, rather than the entire agricultural operation.

“For Florida growers, we hope these tools can help them be more profitable when planting individual new trees or entirely new groves,” Diepenbrock said. “These plants may eventually become impacted by HLB. But we are learning more about living with HLB from the research being done by UF/IFAS researchers and our colleagues globally. That research may give us new tools to use in the long-term management plan for this field, once this initial project is completed.”

Right now, the team has far more questions than answers. Some of them include:

  • What kind(s) of pest management challenges does each tool — for example, insect-proof netting — present?
  • Does the use of reflective mulch (plastic ground cover) impact root diseases?
  • Do these management tools impact the pathogens that cause the disease known as greasy spot?
  • How efficient are these tools at preventing or delaying infection by the bacterium that causes HLB?
  • How will the use of reflective mulch, exclusion bags and/or kaolin clay alter water and nutritional needs?

To help growers answer those questions, Diepenbrock will work with Megan Dewdney, associate professor of plant pathology; Evan Johnson, research assistant scientist in plant pathology; Davie Kadyampakeni, assistant professor of soil and water sciences; and Christopher Vincent, assistant professor of horticultural sciences. All the researchers are faculty members at the UF/IFAS Citrus Research and Education Center in Lake Alfred.

In addition to helping Florida growers, Diepenbrock believes her team’s research results should help scientists around the world.

“For our colleagues in other states who have not been as heavily impacted, we hope that what we learn can be used in their regions to reduce the devastating impacts of this disease,” Diepenbrock said. “And for our colleagues who are in a similar condition of trying to grow citrus in endemic HLB areas, we hope this adds a tool or two for them as well.”

Greening has spread to 40 countries worldwide. In Florida, citrus production volume declined by 71 percent from 2000 to 2017, primarily due to losses from greening, according to UF/IFAS economists. The disease entered Florida in 2005.

Source: University of Florida Institute of Food and Agricultural Sciences