Purple Blotch
The disease develops at wet months or periods of high humidity. Severe infection is usually observe during prolonged periods of leaf wetness.
Image Source: Howard F. Schwartz, Colorado State University, Bugwood.org
What are the symptoms
Symptoms start with small water-soaked lesions with a white center on the leaves; under favorable conditions, the lesions on leaves turn brown with purple margin. More often observe in older leaves than younger leaves.
Impact to the crop
The disease causes the destruction of foliage which may lead to up to 50% yield loss.
How to control
Cultural control includes sanitation, crop rotation with non-host crops, practice good soil drainage and avoid excessive irrigation. The disease can be controlled by chemicals such as benomyl, captafol, carbendazim, chlorothalonil, copper oxychloride, iprodione, mancozeb, thiram and ziram.
Source: Dela Cueva, FM, CB Pascual, CM Bajet and TU Dalisay. 2015. Pests and diseases of economically important crops in the Philippines.Pest Management Council of the Philippines, Inc. c/o Crop Protection Cluster, University of the Philippines Los Banos, College, Laguna
