Bacterial wilt on Arcadia. Photo credit: Phil Harmon.
Bacterial wilt is a relatively new disease that was found in Florida blueberries in 2016. Since its discovery, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) has been studying the pathogen to learn more about its behaviors and methods for management. Phil Harmon, a professor in the Plant Pathology Department at the University of Florida, has been leading the study.
At the recent Central Florida Fruit Grower Day presented by UF/IFAS, Deanna Bayo, a doctoral student in the plant pathology department, gave an update on bacterial wilt. The information presented was from her studies while she has been working with Harmon.
Bayo says that because bacterial wilt is still a new pathogen in blueberries, there is limited data on the pathogen. Right now, she and Harmon are focused on identifying symptoms and finding ways for management.
Symptoms of bacterial wilt on the leaves look similar to those of bacterial leaf scorch. So, there will be marginal leaf scorch starting at the edge of the leaf and moving inward. Another way to see if a blueberry tree has been infected is to put woodchips from the crown of the plant in water. “If you see a milky, cloudy fluid moving out of it (the woodchip), that’s bacterial streaming which can sometimes be seen with this disease, but not always,” Bayo says.
Bacterial streaming. Photo credit: Phil Harmon.
Furthermore, another indicator of bacterial wilt is if the symptoms are moving down the rows faster than across the rows. Bacterial wilt is a soilborne pathogen, so it will move quicker down the rows instead of jumping from one row to another.
Bayo says researchers are currently focusing on excluding the pathogen from production sites. Sanitation is key when trying to manage bacterial wilt. “When it comes into the fields, you’ll want to focus on sanitation of equipment that’s being moved, because this is not only a soilborne pathogen. Since it’s in the vasculature of the plant, that means it’s moving all the way through the roots to the stems,” she says.
Therefore, the pathogen could potentially be all throughout the plant. So when pruning a diseased plant, the pathogen could be transferred to a healthy plant without proper sanitation.
Moreover, moving soil from an infested area to a non-infested area can cause the pathogen to spread. Bayo suggests avoiding the movement of soil altogether. Also, avoiding the use of recycled water is a good method for management.
Bayo also reminds growers the other management suggestions are not methods for control; they are preventive measures. These methods can reduce the likelihood of bacterial wilt entering a production system, but once the blueberries are infected, there is no control yet.
Bayo highly recommends reaching out to the UF/IFAS Plant Diagnostics Center if bacterial wilt symptoms are spotted on your farm. The center can give a more definitive diagnosis.
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