Managing citrus tree growth with hedging and plant growth regulators: strategies for reducing psyllid feeding and huanglongbing infection

Abstract

Reducing excessive vegetative growth that is produced annually by citrus trees in Florida would reduce the opportunities for asian citrus psyllid (Diaphorina citri Kuwayama) reproduction and thereby, the spread of huanglongbing. Excess tree growth is routinely removed through hedging, and branch regrowth can be reduced after hedging in the fall season under Florida conditions because of the onset of cool temperatures. Additionally, late summer hedging may synchronize a final late-season flush, and thus, reduce new flush leaves present during the winter to support overwintering psyllids. We determined timing effects of fall and early winter hedging of ‘Hamlin’ orange trees on vegetative growth flush and subsequent yield during a 2 year period. None of the hedging times tested stimulated a growth flush or significantly affected yield by hedging time in either year.

Reducing excessive vegetative growth that is produced annually by citrus trees in Florida would reduce the opportunities
for asian citrus psyllid (Diaphorina citri Kuwayama) reproduction and thereby, the spread of huanglongbing.
Excess tree growth is routinely removed through hedging, and branch regrowth can be reduced after hedging in the
fall season under Florida conditions because of the onset of cool temperatures. Additionally, late summer hedging may
synchronize a fi nal late-season fl ush, and thus, reduce new fl ush leaves present during the winter to support overwintering
psyllids. We determined timing effects of fall and early winter hedging of ‘Hamlin’ orange trees on vegetative
growth fl ush and subsequent yield during a 2-year period. None of the hedging times tested stimulated a growth fl ush
or signifi cantly affected yield by hedging time in either year.