• Late blight was confirmed in an organic cherry tomato field near Lawrenceville, NJ in Mercer County on 9/8. All tomato growers should continue to scout on a daily basis. Weather conditions have been ideal with the heavy, scattered rain and humid conditions over the past few days across much of the state.
• There have also been scattered reports of late blight have been reported in PA and VA over the past couple weeks.
• Conditions for downy mildew development on many crops have been ideal this past week with the scattered heavy rains, cooler night temperatures and dewy mornings. Downy mildew has been reported on cucumber, basil, and crucifer crops in our area. Remember, the fungicides recommended for controlling downy mildew are specific and need to be incorporated into weekly maintenance applications.
• Cucurbit powdery mildew remains active on many cucurbit crops.

Late blight was reported on tomato in Leesburg, Virginia on 7/21. Leesburg is Northwest of Washington, DC. There have been scattered reports of late blight in the region this summer.

This is a good reminder for all tomato and potato growers in New Jersey and surrounding region to scout on a regular basis. No late blight has been reported in New Jersey to date. For more information on late blight and to track its progress in the US please visit USAblight.

An isolated case of Late blight has been confirmed in Southern New Jersey on a farm that was growing both field-grown and greenhouse-grown tomatoes. The pathogen originated in an old tomato planting that had been unsprayed since the last pick over 6 weeks ago. Left unscouted, the field developed Late blight and the pathogen moved into the greenhouse operation within days of an otherwise healthy-looking greenhouse tomato crop.

As a reminder any crop, conventional or organic, left standing in a field after last harvest will only act to serve as a source of potential incoculum for many diseases. As with tomatoes and other crops, all should be disced down, tilled, and/or mowed down as soon as possible after harvest. Conventionally, applying the herbicide, gramoxone, is also an easy way to achieve this. Organic growers need to be just as diligent and disc down, till, or pull old plantings soon after use.

For more on the control of Late blight in tomato please see the 2013 Commercial Vegetable Production Recommendations Guide.

Late blight in Greenhouse Tomato	Late blight lesions developing on a greenhouse grown tomato plant. Under dryer, less humid conditions the lesions may not have the characterstic dark, greasy appearance.
Late blight in GH Tomato Leaf Underside	Late blight sporulating on the underside of an infected tomato leaf. Note the pure white sporangia (spores) on the underside of the leaf.