Photo by Sam Craft, Texas A&M AgriLife
Texas A&M AgriLife Research is launching a multi-institutional study to develop and evaluate systems that deliver treatments to HLB-affected trees. The principal investigator is Kranthi Mandadi, plant molecular biologist at the Texas A&M AgriLife Research and Extension Center at Weslaco and professor in the Texas A&M Department of Plant Pathology and Microbiology.
The three-year, $1.1 million project is supported by the Emergency Citrus Disease Research and Extension Program from the U.S. Department of Agriculture National Institute of Food and Agriculture.
The project builds on previous collaborative research that identified effective therapies. It brings together researchers from Texas A&M AgriLife, the University of Florida and the University of California, Riverside to improve treatment delivery while minimizing tree damage.
For applied HLB therapies to work, they must reach the tree’s vasculature, where the pathogen resides. Application to the leaves or foliage by spraying does not allow adequate penetration of therapies due to the waxy and thick leaves of citrus.
Current treatments, such as antibiotic injections, have helped slow disease progression and improve yield in affected trees. However, application by trunk injection can cause structural damage, making the treatment method unsustainable for long-term orchard health.
“Citrus growers need alternative and practical vascular delivery approaches, regardless of which therapy is eventually used in the short or long term,” Mandadi said. “Our goal in this project is to develop a more sustainable and scalable system for long-term therapeutic delivery for trees.”
To meet this need, the team plans to focus on two innovative systems that sidestep the need for trunk injection — aerial root systems and inarch graft injections. Both function as alternative entry points for delivering antibacterial compounds directly to where the HLB pathogen resides.
Once established, these systems could act as permanent or semi-permanent channels to enable repeated delivery of therapies without injuring the main tree trunk. “They are less invasive, applicable to citrus trees of different ages and sizes, and they allow for repeatable treatments while minimizing application costs over time,” said Sonia Irigoyen, AgriLife Research senior research scientist.
Source: Texas A&M AgriLife
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