Holmes is conducting fungicide trials in cucumbers to determine which sprays are most effective at controlling downy mildew. He says Curzate (cymoxanil) and Tanos (cymoxanil plus famoxadone) have been effective when applied preventatively in his trials. Previcure Flex (propamocarb hydrochloride) makes an excellent rotational product, along with Gavel, which has zoxamide and mancozeb. In addition, a new fungicide called Hero should be labeled soon to control downy mildew in cucurbits.
Managing resistant varieties is also important.
"As a general principle, disease management should include several tactics and these tactics should change over time. This is especially true for fungicide use as well as the type of plant resistance used," Holmes says.
That's why only an integrated approach will provide for the long-term management of foliar cucurbit diseases such as downy mildew in cucumbers.
"If everybody is on high alert, which I expect they will be, and watching the Web site to see where the disease is and applying systemic treatments in advance, based on how the disease is spreading, that should be sufficient to stay ahead of the disease," Holmes says.