By Tripti Vashisth
In Florida, it is the time of year to start following citrus flower bud induction conditions for next year’s bloom. Citrus flower bud induction starts in the fall and usually is complete by early January.
Low temperatures first stop growth and then promote induction of flower buds as more hours of low temperatures accumulate (below 68 degrees). Periods of high temperatures in winter can then initiate bud differentiation, which after sufficient days of warm temperatures leads to bloom.
The citrus flower bud advisories began on Nov. 21 and are issued every two weeks. Growers are encouraged to pay attention to flower bud advisories as they will cover the current conditions to predict flowering. This information will help growers develop grove management plans for the upcoming season and as well as strategies to enhance yield.
In healthy citrus, a grower’s goal can be to enhance flowering to maximize fruit set and yield. Two common ways of achieving this are application of water stress and application of flower-promoting fertilizers. However, with HLB-affected trees, it is strongly recommended to not use either of these strategies. More information can be found here.
With HLB-affected trees, flowering management tools are limited. However, the flower bud advisories can be used for identifying the best time to apply gibberellic acid (GA). GA induces suppression of flowering, which benefits HLB-affected trees by preserving carbohydrates that can be later used by growing fruit and the tree.
Growers who are considering GA application to suppress flowering should carefully choose the time to spray. GA application should be targeted at a moderate-high flower bud induction period to get the most effect. A late or too early GA application may not be useful in achieving desired results. In addition, flower bud advisories can help with planning for post-bloom drop management and other pest and disease management for spring.
Tripti Vashisth is an associate professor at the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center in Lake Alfred.
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