Cucurbit downy mildew has been confirmed on summer squash in southern New Jersey. This is the first report of CDM on summer squash in the state this growing season. CDM was also confirmed in watermelon on Long Island this week.  Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where other CDM isolates in Clade II predominately infect cucumber and cantaloupe. All cucurbit growers should scout on a regular basis and initiate a weekly CDM fungicide program.

For more information on CDM, the clades, and CDM control please click here.

Cucurbit downy mildew sporulating on the underside of an infected cucumber leaf.

Now is a good time to start thinking about ways to help mitigate cucurbit downy mildew pressure later in the production season. All cucurbit fields, especially cucumber and other summer squash fields should be destroyed immediately after the last harvest to help limit potential inoculum sources for cucurbit downy mildew. For a review of CDM control please click here. To track the progress of CDM on your phone or PC please visit the CDM forecasting website.