Cucurbit downy mildew was reported on watermelon in Dorchester County, Maryland and Sussex County, DE on 7/2.

This is the first report of cucurbit downy mildew in the region to date.  The most recent reports of cucurbit downy mildew on the east coast have been in cucumber and watermelon. There are at least 5 or 6 reported races of downy mildew on cucurbit in the US with each affecting a different set of cucurbit hosts. Unfortunately, very little is known about what races may be present in our region.

All cucurbit growers need to scout on a daily basis and consider adding a downy mildew specific fungicide to their regular maintenance programs. To track the progress of CDM in the US please visit http://cdm.ipmpipe.org/. For more information on the control of cucurbit downy mildew please see the 2015 Commercial Vegetable Production Guide.

Cucurbit downy mildew was confirmed in a 10 acre cucumber field near Rosenhayn in southern New Jersey today.

This is the first report of cucurbit downy mildew in New Jersey this growing season. All commercial cucurbit growers in the state and region should scout their fields on a regular basis. Growers who have not already included downy mildew specific fungicides into their weekly fungicide programs should do so immediately.

Symptoms of cucurbit downy mildew
on cucumber leaf.

If left uncontrolled, cucurbit downy mildew will cause significant losses. For more information on controlling cucurbit downy mildew please see the 2014 Commercial Fungicide Recommendations Guide.

Organic growers can apply copper and other OMRI-labeled products at labeled rates to help suppress downy mildew development under light disease pressure.

Once cucurbit downy mildew (CDM) is detected in the mid-Atlantic region (as of yesterday in Maryland) all cucurbit growers in New Jersey should begin to include downy mildew specific fungicides in their weekly fungicide programs on all cucurbit crops.

Symptoms of cucurbit downy mildew on infected cucumber leaf.

Cucurbit downy mildew has been confirmed on cucumber in Caroline County, Maryland.

This is the first report of cucurbit downy mildew in the mid-Atlantic region this growing season. All cucurbit growers should scout their fields on a regular, if not, daily basis. All cucurbit growers should consider switching to a preventative fungicide program that includes downy mildew specific fungicides. For more information, please see the 2014 Commercial Vegetable Fungicide Recommendations Guide.