By Christopher Vincent, Tripti Vashisth and Gillian Zeng Michalczyk
Hurricane Ian harmed citrus trees in much of Florida, especially in areas where sweet oranges are grown. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers are tracking the health of trees in groves around the state as they struggle to recover. Fall applications of gibberellic acid before the storm helped provide some protection from damage.
Observations confirm what growers have said: Recovery is slow. In most places, canopy volume has not fully recovered since the hurricane. Using a measure of health of the leaves that are on the tree, tree health continued to decline all the way through the dry season and didn’t recover to healthy levels until between May and July of this year, at least eight months after the storm. Some trees died in the last few months.
STRESS MITIGATION METHODS
Post-hurricane management should focus on keeping trees irrigated and/or shaded. Take care of water status in your trees. There was a consistent decline in leaf health through the dry season in the most affected areas, but also in areas where winds never got above Category 1 strength. It has also been observed that, even months later, the stems of Category 1-affected plants had a low capacity to move water. This is probably why these trees had difficulty dealing with the very dry months. Frequent irrigation (daily where possible) and the use of particle films both can mitigate these stressors. So, if your trees are still limping along, consider these approaches to help them recover.
An ounce of prevention is worth a pound of cure. Consider planting windbreaks for any new citrus blocks. Researchers have seen that trees along grove edges were most impacted by Hurricane Ian, while those in the middle of groves were less harmed. Trees on the edge of plantings adjacent to open spaces or bodies of water were most affected. Planting windbreaks helps provide a more buffered environment and reduce the actual windspeed through the grove.
Acknowledgments: Citrus Initiative, U.S. Department of Agriculture National Institute of Food and Agriculture
Christopher Vincent and Tripti Vashisth are associate professors, and Gillian Zeng Michalczyk is a graduate research assistant, all at the UF/IFAS Citrus Research and Education Center in Lake Alfred.
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