After hurricanes hit citrus-producing regions in Florida, there is always one question included in the conversation: How bad is it? Experience has shown that the damage from hurricanes can take months to fully manifest. And recovery can take years, especially in the HLB-era.
Within a week after Hurricane Milton making landfall on Oct. 9, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) hosted a webinar that provided initial information on the storm’s damage and resources available to growers. One of the presenters was Christopher Vincent, UF/IFAS associate professor of horticultural sciences. His talk covered lessons learned from Hurricane Ian that struck Florida in 2022.
WIND IMPACTS
Vincent received a grant from the U.S. Department of Agriculture to study long-term effects of Ian. He, along with his graduate student at the time, Zeng Michalczyk, began monitoring several locations along the path Ian took across the state. Within those locations, they were able to analyze the effects of Category 1 and Category 3 hurricane force winds. Category 2 was not included in the study because the researchers didn’t have access to a grove that experienced Category 2 winds.
Vincent said one of the obvious points observed is that different wind speeds cause different kinds of damage. It is important that growers know what sort of damage is present in groves to help dictate actions aimed at tree recovery.
“Another important point I’d like to emphasize is that damage from high wind speeds can persist for months to years,” he said. “One thing our study did not cover was damage caused by flooding, but it is at least as important as wind damage.”
For Category 1 winds, there will be some fruit on the ground after the storm, but there also will be a fair amount of fruit on the trees. Another observation was that the fruit drop was chronic and continued for an extended period of time after the storm.
“With Category 1, you are going to see some bending of branches, but not as many broken limbs,” Vincent said. “You also will see some defoliation of leaves, but not a massive amount. With Category 3 winds, you are going to see many more limbs broken, extensive defoliation and dramatic fruit drop with almost no fruit left on the trees.”
Vincent noted that data is not available on the impact of wind on roots.
He said the Category 1 and 3 levels of damage lead to different recovery times. He showed photosynthesis data collected from trees that had no hurricane winds compared to Category 1 and 3 winds.
It was observed that even Category 1 winds can restrict water flow in trees because limbs have been bent and twisted. In the case of Category 3 winds, those limbs often are blown completely off.
“This means if a storm is roughly a Category 1, you are more likely to see chronic stress but decent retention of leaves throughout this period,” Vincent said. “With Category 3, you are going to see much more canopy loss, but leaf health is decent for leaves left on the tree or from new flush.”
POST-STORM STRATEGIES
To encourage recovery, irrigation will be critical in each scenario. Trees are stressed from the damage and need to avoid water deficits, which bring even more stress. The mantra to frequently irrigate at lower volumes to help HLB-infected trees holds true in hurricane recovery. And hurricanes occur before heading into the dry season when rainfall is less abundant.
For trees that held more of their canopy from less severe winds, Vincent said another strategy would be to control demand for water in trees. That can be accomplished by the application of particle films.
“Between increased irrigation frequency and applying shading, you can reduce water demand and take some of the edge off a warm and dry period,” he said.
Canopy recovery is going to be the major focus of Category 3 wind damage. This, too, will require adequate irrigation, but also attention paid to ensure fertilization is at proper levels because root damage is likely. In this scenario, rather than applying particle films to reduce water demand, applications of tools like gibberellic acid to enhance new flush and vegetative growth are important.
Vincent also advised not relying on meteorological measurements (such as from weather stations) from the storm to dictate action. Instead, go by what the trees look like after the storm has passed through, he recommended.
“If you see mild defoliation and branch bending, that is like Category 1 damage. If you see major limb breakage and canopy loss, that is going to be Category 3 damage,” he said.
Those observations will be helpful in developing a recovery plan for trees in the weeks and months to come, Vincent concluded.
Share this Post
About the Author
Sponsored Content