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
Onion white rot caused by Sclerotium cepivorum continues to be a major fungal disease of onions in New Zealand The onset of the disease in the Pukekohe area can be predicted by the use of cumulative average daily soil temperatures above a base temperature (white rot degree days) This prediction model was used to determine the optimal timing for fungicide application Analysis of data from trials on timing of fungicide applications conducted between 19892007 showed a correlation between the efficacy of fungicide programme and accumulated degree days with later start times in relation to disease onset equating to a consistent drop in efficacy The disease normally occurs when white rot degree days reach 250 Fungicide programmes commenced above this value achieved relatively poor control Spray programmes should start before the disease is observed in the field with start times between 100 and 200 white rot degree days achieving the best control
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.