Scarring in tamarillo fruit (<i>Solanum betaceum</i>)

Abstract

Fruit scarring in tamarillo (Solanum betaceum) is a cosmetic disorder causing extensive revenue losses to the New Zealand tamarillo growers This study aimed to establish the cause of scarring Three possible causes were tested experimentally (1) fungal infection (2) insect damage and (3) physical injury Inoculation with spore suspensions of Botrytis cinerea (10⁵ spores/ml) at fruitset indicated no association between scarring and infection by this fungus Among seven herbivorous invertebrates recorded on tamarillo greenhouse thrips were the most likely incitants of scarring Applications of thrips to developing fruit in fineweave terylene bags (120 thrips/bag) resulted in corky lesions However these were more superficial than the typical scarring of tamarillo Damaging the epidermis by scratching or removing patches of cells on young fruit produced the characteristic corky scars This suggests that any type of epidermal damage (eg wind rub hail or feeding insect) early in fruit development may cause scarring