By Clint Thompson
Potential disease buildup in the short term and long term is a concern for Florida blueberry growers coping with the aftermath of the recent freeze event. Short-term concerns deal mostly with botrytis. Long-term impacts deal with stem blight, explained Phil Harmon, professor and Extension plant pathologist at the University of Florida Institute of Food and Agricultural Sciences, during a recent post-freeze webinar.
Harmon described the severity of the disease and how growers can expect an uptick in incidence and severity within the next year.
“We can expect a large increase in stem blight problems, like we saw after the 2004 hurricane season, like we saw after the 2010 freezes that occurred within the next year,” Harmon said. “Even next year at this time, we’re going to see additional plant stress result in these plants to come into this disease.”
The disease moves into crowns, either through major roots or canes that are attached near the soil surface. It comes in and causes a brown discoloration in some of those main canes, spreads up into the crown and eventually chokes the plant off to where it’s not able to conduct water and keep itself alive. Harmon outlined management options available for growers.
“What we can do about is try to remove the dead plants from the field in a timely manner and prevent them from becoming sources of inoculum of this pathogen. Hedge out broken canes and remove those jagged wounds,” Harmon said.
“Removing those from the plant reduces the likelihood of a successful infection into the crown. Fungicide applications at the time of pruning, as soon as possible after that pruning have shown to reduce the severity of stem blight.”