FACTORS INFLUENCING PETIOLE SPOTTING (GOMASHO) IN CHINESE CABBAGE.
Numbers of affected leaves and intensity of spotting on mature heads were shown to increase rapidly during cool storage at 1°C, reaching a peak between 14 and 28 days.
Spotting was marginally worse where high rates of nitrogen (500kg/ha N) or phosphorus (550kg/ha P) were used in the field and at high soil pH (8.3). Ammonium nitrate gave more spotting than urea while soil and foliar applied manganese had no effect.
Cultivar differences were identified, with useful tolerance in China Pride, WR Green 60, Treasure Island, Chief and Aichi. Of these, China Pride, WR Green 60 and Treasure Island showed commercial potential. Cultivars widely grown in Western Australia, Kasumi II, Hong Kong and Orient Express all proved to be highly susceptible.