See research results on optimizing gibberellic acid applications to reduce the financial impact of the inputs for Florida growers.
Gibberellic acid (GA) has been shown to have a positive impact on flowering, fruit, and vegetative growth for citrus trees, especially those fighting citrus greening infection. According to a UF/IFAS Tip of the Week article, multiple gibberellic acid applications done over months “have reduced preharvest fruit drop and increased yield in huanglongbing (HLB)-affected sweet oranges.“ However, the applications are expensive, costing a minimum of $50 an acre, according to the article. This means that fine-tuning the applications is in the best interest of citrus growers to fine-tune applications to get the most bang for your buck. See the results of research that aim to optimize GA applications below.
Research for Optimizing Gibberellic Acid Applications
According to the article, “There are some questions about the efficacy of day applications versus night applications. Anecdotal observations suggest that at night, GA efficacy is higher than daytime use (since trees at night have a longer time to absorb GA) and therefore, some growers have considered nighttime GA application. Consequently, some growers have also considered reducing the number of applications to one or two if completed at night.”
Research was conducted to test the anecdotal observations, especially since “night applications can be complicated and expensive.” The results of morning versus evening gibberellic acid applications include:
- “Consecutive GA foliar application every three months improved the number of leaves by more than 70% in the morning (AM) application.”
- “With the evening application, the increase was around 50% over the control.”
- “In leaves after four days from the third GA application, the superoxide dismutase and the peroxidase activities (the enzymes related to oxidative stress mitigation) were 30% higher in both GA PM and GA AM conditions in comparison to control trees.”
- “The application of GA influences in a non-univocal way the phytohormones content with a rise of JA, JA-ILE and OPDA amount in the GA AM and an increase of IAA-Asp, SA and tZR content in the GA PM.”
The research summarized that “these results further suggest that evening applications are not better than morning applications. In addition, multiple applications of GA are needed for the desired vegetative growth effects.”
Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions or concerns about your farm or pasture, contact us and one of our team will be in touch.