Growing degree days since April 1: 2406 GDD (Average (11 year): 2203) (From the Illinois State Water Survey Degree-Day Calculator)
4 inch soil temp: 78.7°F (10 am 4-inch soil temperature under bare soil) (From the Illinois State Water Survey Illinois Climate Network)
Downy mildew of cucurbits. Last week, Dr. Mohammad Babadoost shared information about the observations of Downy mildew in two locations in Illinois - a watermelon field in Lawrence County on July 23 and a processing pumpkin field on July 30 in Mason County and the fact that the pathogen will likely spread to other parts of the state.
"Downy mildew of cucurbits, caused by Pseudoperonospora cubensis, is a very destructive disease of cucurbits. The present strain of the pathogen will likely infect all cucurbit crops (cucumber, gourd, muskmelon, pumpkin, squash, and watermelon). Weather conditions in Illinois are very conducive for development of downy mildew.
Downy mildew affects leaves only. Symptoms of downy mildew vary with the host and the environmental conditions. The first symptom is usually the appearance of indistinct, pale green areas on the upper leaf surface. The pale green areas soon become yellow in color and angular to irregular in shape, bounded by the leaf veins. As the disease progress the lesions may remain yellow or become brown and necrotic. During moist weather the corresponding lower leaf surface is covered with a downy, pale gray to purple mildew. Often an upward leaf curling will occur.
If you don't have the disease in your field yet, include chlorothalonil (e.g., Bravo Weather Stik) in your weekly sprays. When you observe downy mildew in your field, you need to spray your cucurbit crops with one the following fungicide combination at weekly interval: Revus 2.09SC or Previcur Flex 6SC or Tanus 50WG or Ranman 3.6SC or Gavel 75DF or Zampro 525F plus chlorothalonil. For additional information, contact Mohammad Babadoost by email (babadoos@illinois.edu) or by phone (217-333-1523)."
Organic growers can check out the ATTRA publication,"Downy Mildew in Cucurbits" at http://attra.ncat.org/attra-pub/downymildew.html#ref4.
Last week, I mentioned the opportunities to celebrate National Farmers Market Week in Springfield. Had a lot of fun today sharing information about the resources available form the University of Illinois Extension at the Old Capitol Farmers Market. The week-long events aim to raise awareness for Springfield's four farmers markets and the importance that they play in creating healthy, vibrant communities. Click here for more information.
Source: University of Illinois Extension