Cucurbit downy mildew has been observed on cucumber in LaPorte County and LaGrange Counties, in northern Indiana and Knox County in the southwest. Downy mildew of cucurbits has also been reported in Kentucky and Michigan. See this article (https://vegcropshotline.org/article/cucurbit-downy-mildew/) in the last Hotline issue about details of downy mildew.
Whether growers manage for downy mildew at this late date will depend on when last harvest is anticipated. Cantaloupe and watermelon growers who plan a final harvest at or close to Labor Day should not have to apply any specialized fungicides. Pumpkin growers often start to harvest in early September. Such growers will have little to worry about from downy mildew. However, cucurbit growers who anticipate harvesting fruit that is still developing may want to consider products that were discussed in the last issue of the Hotline. Remember, downy mildew doesn’t affect the fruit directly. Downy mildew affects fruit development by reducing foliage. Note that jack-o-lantern pumpkins require 60 to 90 days from pollination to market maturity. First frost over much of Indiana will occur in mid-October.