Boysenberry decline identification and control of a serious disease of boysenberries

Abstract

The fungus Cercosporella rubi which causes rosette of boysenberry was identified in 1998 as the cause of boysenberry decline in New Zealand A fungicide trial was carried out in the summer of 1998/99 to determine the efficacy of several fungicides for controlling rosette The fungicides azoxystrobin benomyl bitertanol difenconazole mancozeb and pyrimethanil were each applied five times to boysenberry primocanes in a commercial planting of boysenberries from November through to February Difenconazole was the most effective fungicide for reducing rosette symptoms while azoxystrobin and benomyl also gave good control of the disease This trial has demonstrated that several fungicides from different chemical groups could be used for control of rosette