Factors affecting blemishing of persimmon in New Zealand and Australia

Abstract

Blemishing is a major quality defect of persimmon both in Australia and New Zealand. Several studies were conducted on the incidence and development of blemish in 4 well-managed orchards in both countries. Over 10 different types of blemishing were identified and documented. Of the blemishes identified, wind rub caused the greatest reduction in marketable fruit. The occurrence of this disorder was 5 times higher in Australia than in New Zealand in spite of windrun in New Zealand being 2–2.5 time higher than in Australia. The lower incidence of wind rub in New Zealand appears to be due to the use of Y trellising, whereas, in Australia, trees are free-standing. The incidence of sunburn varied markedly with season. The incidence of this disorder was reduced by bird-netting (5-15% shade factor) which is the standard management practise in Australia. Line, apex and concentric cracking were minor problems in most orchards. Methods for controlling blemishing in commercial orchards are outlined.