The August episode of the All In For Citrus podcast takes listeners on a deep dive into the use of plant growth regulators like gibberellic acid (GA) to help fight fruit drop. The episode features an in-depth conversation between Michael Rogers, director of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center, and Tripti Vashisth, UF/IFAS associate professor of horticultural sciences. They cover subjects such as the number and timing of applications of GA to optimize tree response. While GA research has been discussed before, podcast host Frank Giles noted that this is the most comprehensive conversation he’s heard to date on the subject.

Vashisth has been on the forefront of research on the use of GA in Florida citrus. Over the years, this research has led her to refine application recommendations to improve GA performance. Studies have shown that multiple applications of GA produce the best results. UF/IFAS now recommends up to five applications. But what about growers who can’t afford five applications? Rogers and Vashisth discuss this challenge facing many growers and offer guidance on how much can be cut back without diminishing GA application return-on-investment.

The conversation covers GA applications for both Valencia and Hamlin oranges, which respond differently to the treatments. There also has been some anecdotal observations that GA applications made at night perform better than in the daytime. Vashisth offers guidance on this topic in the podcast.

In addition to GA, Rogers and Vashisth discuss new and ongoing research on the use of 2,4-D to improve fruit retention in HLB-affected oranges.

Growers interested in fighting fruit drop with plant growth regulators will not want to miss this episode of All In For Citrus. The podcast is a joint project of UF/IFAS and AgNet Media.