A University of Florida researcher who helped develop a mathematical model to show how citrus greening spreads within infected trees has received a $300,000 grant from the Esther B. O'Keeffe Foundation to expand the model.
Ariena van Bruggen, a UF plant pathology professor, received the award so she can study the best strategies to combat citrus greening from tree to tree. There is no cure for citrus greening, but methods being used to slow the disease include removal of symptomatic trees, insect control and attempts to boost the tree's immune system, van Bruggen said.
"I want to find out with this model which is the more important part of the solution," she said. "Can we actually boost the immune system of the tree enough so that that would give you proper control? More likely it's a combination of factors. But perhaps the moving of diseased trees, as it has been done so far, is not going to be as effective."
Removing diseased new growth--called flush, or shoots--solves little, the current model shows. Even without showing symptoms, many shoots may already be infected. That means other tree parts can get infected.
The model developed by van Bruggen and colleagues was published in 2012 by the journal Proceedings of the National Academy of Sciences. It showed that once a tree is infected, insecticides applied early on may only slow, rather than halt, the disease's progression.
Citrus greening was first detected in Florida in 2005 and has cost the state's citrus industry an estimated $4 billion and 6,000 jobs since 2006. It poses a huge threat to the state's $9 billion industry. In Florida, because of the disease, the U.S. Department of Agriculture says this year's orange crop will be off 9 percent from last season.
Foundation trustee Brian O'Keeffe said van Bruggen's research provides crucial information to understand the spread of citrus greening.
"Such increased understanding could help develop better techniques in hopefully managing the disease," O'Keeffe said.
The importance of such studies has been underscored in the past month by the U.S. Department of Agriculture's $1 million additional research funding to its emergency response against citrus greening spreading nationwide, he said.
"Understanding the transmission of the disease within an infected tree is essential to try to defend the existence of Florida's and many other states' citrus industries," O'Keeffe said.