Studies on White Scaled Lesion on Citrus

Citrus white scaled lesion is a disease producing white spotted, linear, branched, circular or irregular scaled lesions on peel, simply causing epidermal cells putrescence. The pathogens were identified as Colletotrichum gloeosporioides Penz, Botryodiplodia theoboromae Pat. and Alternaria citri Ell.et Pierce, which infected citrus fruits independently or mixedly. The diseased trees in the field were an important resource of the pathogens. The disease started in the middle of May. The peak of infection was in the middle of July. The resistance of Pengnuo navel orange to the disease was the highest among the tested citrus species (varieties). The incidence of disease could be greatly decreased by covering fruits with bags. The better control efficiency (up to 60%) could be obtained by spraying lime sulfur.