Rutgers Cooperative Extension
The effects of a cold night a few weeks ago are showing up in some varieties of cucumber around New Jersey. Symptoms on maturing fruit appear as brownish-tan areas on the epidermis of fruit. The fruit will also show cracking as if it has a dry rot. The effects are physiological where areas of young developing fruit got chilled by the cold night time temperatures.
Cold injury on cucumber fruit. The initial damage was done a few weeks ago while the fruit was very young.
Cercospora leaf spot can significant losses in beet if not controlled properly.
Cercospora leaf spot on beet. Note the round tan leaf spots with dark red margins.
The fungus overwinters in soils and be a continual problem in fields with short crop rotations. It has developed resistance to important fungicides in beet production areas in the US and abroad. Resistance has been detected in the Benzimidazole fungicides (FRCA code 1); the DMI fungicides (Tilt, tebuconazole; FRAC code 3) and the strobilurin fungicides (Quadris, Cabrio, Headline; FRAC code 11). Beet growers in NJ who have relied heavily on, and are not obtaining adequate control of Cercospora with either DMI or strobilurin fungicide applications in their weekly programs should discontinue their use. These growers should switch to fungicides with different modes of action such as Fontelis (penthiopyrad, 7) at 16.0 to 30.0 fl oz/A (3 day PHI) and Merivon (fluxapyroxad + pyraclostrobin, 7 + 11) at 5.5 fl oz/A (7 day PHI). Growers who are still obtaining adequate control with either the DMI or strobilurin fungicides can continue their use, but should make efforts to incorporate the use of the mentioned fungicides above to help reduce the chances for resistance development.
Late blight has been found in small cherry tomato field near Roadstown, NJ today where 100% of the field is affected. This is the third report of Late blight in New Jersey this year and the first since 9/8.
Cool day and night temperatures with prolonged dews are ideal for Late blight development, especially in fields where no protectant fungicides have been applied in recent weeks.
All growers who are still in tomato production should continue to scout on a regular basis and apply protectant fungicides. Abandoned commercial fields, need to be disked under or sprayed with gramoxone to kill all living tissue. All abandoned organic fields should be disked under or plants should be pulled and discarded.
Late blight was found in an organic tomato field near Bridgeton today, August 14. This is the first report of late blight in New Jersey this growing season.
Weather conditions this past week have been favorable for its development in most of the mid-Atlantic region. All tomato and potato growers in the state should scout their fields on a regular basis. All tomato and potato growers who have not initiated a protectant fungicide program should do so. For more information on controlling late blight please see the 2014 Commercial Vegetable Production Recommendations: Tomato Section, page F205 and Potato Section, page F128.
If you suspect late blight on your farm please contact your County Ag Agent.
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