Control of flyspeck (Schizothyrium pomi) on Actinidia arguta kiwifruit

Abstract

Flyspeck, caused by Schizothyrium pomi (anamorph Zygophiala jamaciensis), is a serious cosmetic skin disorder of Actinidia arguta kiwifruit in New Zealand. In a study of the disease in 2009-10, the bark of all 1-year-old canes was carrying large numbers of characteristic dark fruiting bodies (thyriothecia) (flyspecks). Germinating spores and hyphae of S. pomi were first observed on current season's canes in December 2009. Flyspecks were first found on fruit in mid-January 2010 and their incidence and severity increased until harvest in February 2010. Sprays of trifloxystrobin or carbendazim applied pre-blossom and during flowering reduced the incidence of fruit with flyspeck at harvest by an average of 70% compared with the untreated control. A single application at either of those times was similarly effective with one exception; trifloxystrobin applied as a pre-blossom spray failed to control flyspeck. Carbendazim residues (0.02 mg/kg) were recorded in the fruit at harvest following an application during flowering. © 2012 New Zealand Plant Protection Society (Inc.).