TEXAS A&M AGRILIFE LEADS MULTISTATE COLLABORATION AGAINST HUANGLONGBING DISEASE
New research takes aim at devastating citrus greening
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itrus greening, or Huanglongbing disease, HLB, is the most devastating disease for orange and grapefruit trees in the U.S. Prevention and treatment methods have proven elusive, and a definitive cure does not exist. Since HLB was detected in Florida in 2005, Florida’s citrus production has fallen by 80%. The disease also threatens other citrus producing states. Now, a public-private collaboration across Texas, Florida, California and Indiana will draw on prior successes in research and innovation to advance new, environmentally friendly and commercially viable control strategies for citrus greening. Leading the work are scientists from Texas A&M AgriLife Research.
$7 million USDA project The $7 million, four-year AgriLife Research project is part of an $11 million suite of grantsfrom the U.S. Department of Agriculture National Institute of Food and Agriculture, NIFA, to combat HLB. The coordinated agricultural project is also a NIFA Center of Excellence. “Through multistate, interdisciplinary collaborations among universities, regulatory affairs consultants, state and federal agencies, and the citrus industry, we will pursue advanced testing and commercialization of promising therapies and extend outcomes to stakeholders,” said lead investigator Kranthi Mandadi, Ph.D., an AgriLife Research scientist at Weslaco and associate professor in the Department of Plant Pathology and Microbiology at the Texas A&M College of Agriculture and Life Sciences. In addition to Texas A&M AgriLife, other institutions on the team include Texas A&M University-Kingsville Citrus Center, University of Florida, Southern Gardens Citrus, University of California Agriculture and Natural Resources, Purdue University, and USDA Agricultural Research Service. “This collaboration is an inspiring example of how research, industry, extension and outreach can create solutions that benefit everyone,” said Patrick J. Stover, Ph.D., vice chancellor of Texas A&M AgriLife, dean of the College of Agriculture and Life Sciences and director of Texas A&M AgriLife Research.
Industry leaders stress the urgent need for solutions. “As a grower myself, and looking into the future of our citrus industry, we see lots of uncertainty because of the devastation that HLB has
A healthy grapefruit compared to one affected by citrus greening (Texas A&M AgriLife photo)
caused the Florida citrus industry,” said Dale Murden, president of Texas Citrus Mutual and Pest and Disease Management Corporation. “We need to look into real and practical solutions for the HLB threat. I believe this project is timely and essential.”
HLB solutions must overcome known challenges An effective HLB treatment must avoid numerous pitfalls, Mandadi explained. One major problem is getting a treatment to the infected inner parts of the tree. The disease-causing bacteria only infect a network of cells called the phloem, which distributes nutrients throughout a tree. Starved of nutrients, infected trees bear low-quality fruits and have shortened lifespans. Treatments must reach the phloem to kill the bacteria. So, spraying treatments on leaves has little chance of success because citrus leaves’ waxy coating usually prevents the treatments from penetrating. Second, while the bacteria thrive in phloem, they do not grow in a petri dish. Until recently, scientists wishing to test treatments could only do so in living trees, in a slow and laborious process. Third, orange and grapefruit trees are quite susceptible to the disease-causing bacteria and do not build immunity on their own. Strict quarantines are in place. Treatments must be tested in groves that are already infected.
Two types of potential citrus greening therapies will be tested using novel technologies The teams will be working to advance two main types of treatment, employing technologies they’ve developed in the past to overcome the problems mentioned above.
