Leaf Spot

Recognizing Angular Leaf Spot in Cucurbits

Plant & Pest Advisory – July 23, 2025 – Andy Wyenandt

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Angular leaf spot, caused by the bacterium (Pseudomonas syringae pv. lachrymans), is common inNew Jersey and the region. Although it often shows up during cooler, wet weather; it can show upalmost anytime during the production season with favorable weather conditions for its development.Angular leaf spot will first appear in ‘hot spots’ as, small water-soaked lesions […]

Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley

Plant & Pest Advisory – May 27, 2024 – Andy Wyenandt

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Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established.Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or […]

Bacterial Leaf Spot Control and Copper Resistance in Pepper and Tomato

Plant & Pest Advisory – May 31, 2024 – Andy Wyenandt

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Copper resistance in bacterial leaf spot of tomato and pepper crops has been detected at a high level inNew Jersey the past few summers. While not surprising, copper resistance has been known to develop for decades now. Copper applications for the control of bacterial diseases in many crops has been a mainstay for decades now […]

Identifying and Controlling Common Leaf Spot in Strawberry

Andy Wyenandt, Rutgers Cooperative Extension

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Strawberry leaf spot, caused by the soil-borne fungal pathogen, Mycosphaerella fragariae, can infectleaves, petioles, runners, fruit stalks (pedicels), and berry caps or calyxes. Small, dark purple to reddish purple, round spots, 1/8 to 1/4 inch in diameter (3 to 6 millimeters), appear on the upper leaf surfaces. The center of the spots soon become tan […]