Selective pruning and crop removal increase early-season fruit production of carambola ( Averrhoa carambola L.)

Abstract

Carambola ( Averrhoa carambola L.) trees grow and bear fruit year-round in their native, tropical environment. Fruits of this species are borne mainly on the canopy periphery, and the delicate skin is easily damaged during windy conditions (wind-scar). Pruning, as well as fruit drop caused by strong winds, stimulates re-bloom of carambola trees. In subtropical southern Florida, cool temperatures and dry winds during the winter inhibit tree growth and shorten the production season to July–February. Crop value is greatest during the early part of the season. We evaluated manual, selective pruning and crop removal as techniques for increasing production of early-season fruit in ‘Arkin’ carambola. Pruning 3–4-year old branches to their main axes in early March (late winter in the Northern Hemisphere) resulted in flowering during mid-April (mid-spring) and a crop by the end of June (early summer), whereas harvest of intact, non-pruned trees began 4–5 weeks later. Pruned branches produced 15 kg (November pruning) to 24 kg of fruit (July pruning). Selectively pruned branches deep within the tree canopy did not appear to be moved by wind as much as branches along the canopy periphery. Thus, fruit from pruned branches were nearly 100% free of wind-scar and had excellent appearance. In comparison, more than 58% of fruit harvested from the canopy periphery had wind-scar, with only ca. 20% free from such damage. Crop removal in November or December (mid–late-autumn) increased early bloom and the amount of early fruit produced in the summer. De-fruited trees produced an average of 48 kg per tree of early fruit, harvested July 7, whereas non-de-fruited trees produced an average of only 5 kg per tree.