What Can Growers Do Post-Ian to Improve Groves?

LAKE ALFRED, Fla. ­– While Hurricane Ian’s impact on Florida’s citrus growers last week is still being assessed, producers can take action now to protect their groves from further damage. 

citrus groves
Photo courtesy of UF/IFAS

Faculty at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center in Lake Alfred, and at the Southwest Florida Research and Education Center in Immokalee, recommend quick attention to prevent further damage to vulnerable root systems and future fruit drop.

Flood waters resulting from heavy rains can severely impact roots already diminished because of HLB (Huanglongbing or citrus greening) disease. Phytophthora is a pathogen that attacks citrus tree roots which are already weakened by HLB. Wet conditions increase the possibility of phytophthora infection in groves with a history of problems. If standing water occurs in groves with phytophthora problems, growers should evaluate for root damage and treat accordingly.

Hurricane Ian caused fruit to drop from trees but also weakened fruit that remained on trees. Tripti Vashisth, associate professor of horticulture, recommends applying gibberellic acid (GA) in the next few weeks and prior to Oct. 30 to support the tree’s ability to hold on to its fruit.

“Extensive leaf loss is going to stress already stressed trees. It is quite likely that extensive leaf loss with good soil moisture will induce new growth. GA application at this time can help with rehabilitating the trees and improving the leaf growth,” Vashisth explained. 

Some growers are already using GA in a series of applications to improve fruit production and are advised to continue. Growers not using GA in this way should make at least one application to encourage leaf growth lost to the hurricane. This will support future fruit production.

Tree defoliation also poses the risk of Asian citrus psyllids being attracted to any new flush that the trees produce. Growers need to watch for pest flareups associated with intense flushing later in October in those areas that were heavily defoliated by Ian.

UF/IFAS engages in several efforts related to disaster response and recovery in the aftermath of natural disaster events, including Hurricane Ian. One of those efforts is to collect and provide information on the impacts of natural disasters on affected agricultural operations.

The UF/IFAS Economic Impact Analysis Program has deployed an updated, streamlined version of its assessment tool to assess the impacts of Hurricane Ian. The UF/IFAS Agricultural Damage and Loss Assessment survey was distributed via UF/IFAS social media pages immediately after the hurricane and will continue to be shared via Florida Cooperative Extension and collaborating industry associations. The assessment tool will be open for several weeks to allow for data to continue coming in from areas that have experienced the most intense impacts.

Additional information regarding post-hurricane measures, including information on insurance and disaster relief claims, may be found in the Citrus Producers Guide to Hurricane Preparations and Recover in the Southeastern United States, written by UF/IFAS assistant professor Fernando Alferez and Mongi Zekri, UF/IFAS Extension citrus agent.