Symptoms and Control Methods of Ginger Leaf Spot Disease

[Pathogen scientific name] Phyllosticta zingiberi Hori

[Host crops] Ginger, white cardamom.

[Disease diagnosis] Mainly affects leaves. Leaf spots are spindle-shaped or oblong, 3-5 mm long, with brown margins and yellowish-white, thinned centers that easily rupture or perforate; later, numerous small black dots appear on the surface of the spots. When the disease is severe, the entire leaf is densely speckled with spots. The pathogen is Phyllosticta zingiberi. The fungal pycnidia are spherical to flattened spherical, dark brown. Conidia are single-celled, elliptical.

[Disease development pattern] The pathogen overwinters in soil as mycelium and pycnidia with diseased plant residues. The following year, overwintered pathogens produce conidia that spread to ginger leaves and cause infection in the field. After infection, conidia produced on diseased tissues are spread by wind and rain for secondary infection. Secondary infections occur frequently, and the disease develops rapidly under suitable conditions. The pathogen favors warm and humid conditions; warm, humid weather, dense plant growth, and high field humidity promote disease occurrence. The occurrence and development of the disease are closely related to the number of rainfall events and the amount of rainfall.