July 5th

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Phytophthora Blight of Cucurbits and Peppers

Phytophthora blight of cucurbits, caused by Phytophthora capsici, is the most destructive disease of cucurbits (cantaloupe, cucumber, pumpkin, squash, watermelon, zucchini) and peppers in Illinois. This disease causes up to 100% yield losses. The pathogen can strike the host plant at any growth stage during the season. Major symptoms of the disease are seedling death, leaf spot, stem lesion, foliar blight, and fruit rot. In the past four years, the disease has been observed in various parts of state. During the past two weeks, Phytophthora blight was observed in pepper fields in the south and in pumpkin fields in central Illinois. Due to the existing conducive environmental conditions, Phytophthora blight is expected to be observed in cucurbit, eggplant, and pepper fields in various parts of the state. The disease usually occurs in the lower spots of the field first and rapidly spreads throughout the field. The most effective control measures are to keep soil moisture as low as possible, avoid working in the field when plants are wet, destroy (e.g., burry) early infected plants, and apply dimethomorph (Acrobat 50 WP) plus a copper compound according to the labels (http://www.cdms.net/ldat/ld4ES001.pdf). The rate of Acrobat is 6.4 oz product per acre and applied on a 7-day interval. For more information on Phytophthora blight of cucurbits and pepper, click here and here.