Florida avocados are facing renewed pressure from avocado sunblotch viroid (ASBVd), a disease that can stunt tree growth, deform fruit, and spread undetected through orchards. Researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) are calling on growers, nurseries, and the public to take measures to contain the disease.
"Avocado sunblotch viroid is an insidious threat to avocado production worldwide and, if not controlled, will result in a loss of fruit production and quality," said Jonathan Crane, tropical fruit crop specialist at the UF/IFAS Tropical Research and Education Center (TREC).
The viroid spreads through root grafts, pruning or grafting tools, propagation materials such as budwood and seed, and pollen carried by honeybees. Yield losses can reach 80%. Symptoms include blotched or streaked fruit, unusual coloring on stems and leaves, or reduced yields, although symptom-free trees can still transmit the viroid through seeds or pollen.
Romina Gazis, associate professor of plant pathology and director of the Plant Diagnostic Clinic at TREC, noted that expansion of Florida's avocado production increases the risk. "Hundreds of grafted avocado trees are being produced to establish orchards in new areas, driving the industry's expansion northward," she said. "At the same time, growers are replanting in orchards where trees were lost to laurel wilt. Because our industry relies on seedling-grafted trees, and the seeds themselves may carry the viroid, it's critical to scout and test for its presence to protect new plantings."
Currently, Florida does not have an industry certification program ensuring budwood or seeds are free of ASBVd. In past decades, growers identified symptomatic trees and worked to contain the spread, but UF/IFAS warns that without renewed attention, the viroid could increase again, particularly with replanting after laurel wilt losses and new plantings in Central Florida.
UF/IFAS scientists recommend annual testing of budwood in nurseries, training orchard workers to recognize potential ASBVd symptoms, and monitoring in packinghouses. Infected trees should be removed completely, and equipment must be sanitized. Homeowners with avocado trees are also advised to watch for signs, test trees, and remove those confirmed with the viroid.
"Historically, Florida's avocado growers, nurseries, and packers were much more aware of ASBVd and worked collaboratively to eliminate ASBVd trees," said Crane. Gazis added, "Today, many new growers and nurseries are not aware of this threat to the industry, but with our UF/IFAS Extension renewed effort to educate the industry, we can once again control this disease."
Source: Lake O News
