Flowering Intensity, Shoot Dieback and HLB

Tacy CalliesHLB Management


Citrus trees grown in Florida continuously undergo various types and levels of stress. Stressors can include severe weather conditions, soil pH, chemicals, pests and diseases. The constant presence of HLB and psyllid infestation adds further stress to the tree, compromising overall tree health.

Off-season flowering and prolonged flowering are common responses of trees when undergoing various stress conditions. Off-season and prolonged flowering typically are not huge concerns, but when they are combined with heavy rainfall and warm weather conditions, they can make grove management difficult and increase the threat of postbloom fruit drop.

Tripti Vashisth, assistant professor of horticulture at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center, recently discussed HLB’s effect on flowering in citrus trees during the new UF/IFAS OJ Break webinar series.


According to Vashisth, a recent UF/IFAS study among Valencia and Hamlin varieties revealed that there was zero correlation between floral intensity and HLB severity.

“HLB does not affect flowering by regulating the citrus floral development, but reduces viable buds for flower formation,” Vashisth explains.

Although no correlation was found between HLB severity and flowering intensity, researchers found that shoot dieback is closely related to HLB severity.

“One of the major concerns for severely HLB-affected trees is there is a greater presence of shoot dieback,” Vashisth says.

Given this information, she recommends growers do not try to solve this issue with flower-enhancing fertilizer. “Flowering is not an issue; limited viable wood is the real concern,” she says.

Improving tree canopy should be top priority for growers, Vashisth advises. Improving tree canopy will provide a wealth of benefits, including increased productivity, fruit quality and overall tree health. Vashisth also recommends growers keep their trees irrigated during the fall to reduce drought stress and off-season flowering.

This article was written by Ashley Robinson, AgNet Media communications intern in Gainesville, Florida.

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