- Basil downy mildew has been reported in Northern New Jersey this past week. All basil growers should continue to scout and be proactive.
- Late blight has been reported on potato as far north as North Carolina near the Virginia border. There have been no reports of late blight in the region to date. To track late blight in the US please visit http://usablight.org/
- Cucurbit downy mildew has been reported on cucumber, butternut, acorn, and yellow summer squash as far north as central South Carolina. To track the progress of CDM in the US please visit http://cdm.ipmpipe.org/
- Bacterial leaf spot are coming in on pepper and tomato.
- Black leg has been reported in potato in southern New Jersey.
- Phytophthora blight on pepper and cucurbit crops has been reported. The heavy rains that have come into and remain in the region have been ideal for P. capsici. All growers need to scout on a regular basis and be proactive.
- Early blight has been reported in tomato.
June 23, 2015 Andy Wyenandt
Vegetable Disease Briefs – 6/23/15
June 14, 2015 Andy Wyenandt
Vegetable Disease Update – 6/14/15
Potato
Black Leg – Black leg is caused by Erwinia spp. which also cause ‘soft rots’. The bacteria which lead to the aerial phase of Blackleg are soil-borne (originate from old crop debris) and spread by rainfall, overhead irrigation and wind. The aerial phase of Blackleg does not originate from decaying seed pieces. The bacterium can enter the plant through wounds created by cultivation or through stems damaged by blowing wind, sand or hail. Dense canopies, warm weather and prolonged periods of leaf wetness favor the spread of aerial Blackleg. Fortunately, the disease rarely extends below ground and only causes dieback of stems over time. Symptoms of the aerial phase of Blackleg first appear as an irregular, water-soaked ‘green’ decay on stems that turns light-brown to black over time. Hot, dry weather will cause infected areas to dry out and become brittle. Do any cultivating when plants are dry, cultivating in the presence of dew or wet plants may help to spread the bacterium around.
June 14, 2015 Andy Wyenandt
Vegetable Diseases of the Week – 6/14/15
This week:
Sweet Basil – Basil downy mildew
Bell Pepper – Bacterial leaf spot
Symptoms of basil downy mildew infection
on Sweet Basil.
Basil downy mildew sporulating on
the underside of infected basil leaf.
Bacterial leaf spot of bell pepper.
June 14, 2015 Andy Wyenandt
Vegetable Disease Briefs 6-14-15
- Basil downy mildew has been reported in New Jersey. All growers should be scouting on a regular basis and applying protectant fungicides.
- Late blight was reported on potato in northern North Carolina near the Virginia border on this past week. There have been no reports of late blight in the region to date. To track late blight in the US please visit http://usablight.org/
- Cucurbit downy mildew has been reported on cucumber, butternut, acorn, and yellow summer squash as far north as central South Carolina. To track the progress of CDM in the US please visit http://cdm.ipmpipe.org/
- The first reports of bacterial leaf spot are coming in on pepper and tomato.
- Black leg has been reported in potato in southern New Jersey.
June 3, 2015 Andy Wyenandt
Basil Downy Mildew Reported: Southern New Jersey – 6/3/15
Basil downy mildew (Peronospora belbahrii) has been found in a field near Vineland, New Jersey. This is the first report of downy mildew in field-grown basil in New Jersey this year. All basil growers need to scout on a daily basis and initiate a preventative fungicide program.
May 31, 2015 Andy Wyenandt
White Mold in Greenhouse & High Tunnel Tomato
White mold, or timber rot, caused by the soil-borne fungal pathogen, Sclerotinia sclerotiorum, was found this past week in a high tunnel.
High tunnel tomato plant with main stem infected by white mold.
White mold is common and once introduced into a field or high tunnel it can very difficult to control. The pathogen produces black sclerotia on the surface and inside infected stems. Sclerotia, if they make their way back into the soil, can survive for years causing significant problems.
Infected stems will turn a light brown color and dry up becoming brittle. If the main stem is infected the entire plant will collapse looking like a wilt or root rot issue.
Under hot, humid conditions white fungal growth will develop on the surface of the stems and in some cases sclerotia will develop on the outside of the stem. Breaking open the stem will reveal numerous black sclerotia.
All infected plants and or plant material need to be removed from the greenhouse or high tunnel immediately and disposed of properly. Preventative protectant fungicide programs beginning at flowering will help control white mold. Cool, wet weather and poor air circulation favors disease development.
Tomato stem infected by white hold. Note the fungal growth on the surface of the stem.
White mold of tomato. Note the black sclerotia developing inside the brittle stems.
