- Anthracnose has been found in spinach in southern New Jersey.
- All leafy greens can be predisposed to leaf spots and blights when overhead irrigation has been used extensively during periods of hot, dry weather. This has especially been true in southern NJ this past week.
- There have been no new reports of basil downy mildew in NJ this past week.
May 10, 2015 Andy Wyenandt
Vegetable Disease Briefs – 5/10/15
May 10, 2015 Andy Wyenandt
Vegetable Disease Update – 5/10/15
Cole crops
Downy Mildew and Alternaria – Symptoms of downy mildew include purple to yellowish-brown spots on upper leaf surfaces. A grayish-white spore mass will develop and cover the underside of leaves under ideal temperatures (night temperatures of 46 to 61°F and day temperatures below 75°F. Downy mildew can kill young plants. Heavily infected leaves may drop providing entry points for bacterial infections (black rot and soft rot). Symptoms of Alternaria on infected leaves include small, expanding circular lesions with concentric rings that may have a ‘shot-hole’ appearance as lesions age. Heavily infected seedlings may result in damping-off. Control of Downy mildew and Alternaria begin with preventative fungicide applications. Please refer to pages F34-35 of the 2015 NJ Commercial Vegetable Production Recommendations to determine which fungicides are labeled for each specific crop and disease. [Read more…]
May 4, 2015 Andy Wyenandt
Angular Leaf Spot in Strawberries
Often considered a minor pathogen, angular leaf spot caused by the bacterium, Xanthomonas fragariae, can cause serious leaf and calyx infections ruining the marketability of fruit if left uncontrolled. Like all bacterium, the pathogen will infect leaves and the calyx through natural openings or wounds.
Fig. 1. Water-soaked lesions caused by angular leaf spot on infect strawberry leaf. Photo by P. Nitzsche
[Read more…]
May 4, 2015 Andy Wyenandt
Strawberry Fruit Rots 2015
Anthracnose Fruit Rot of Strawberry
Pathogens such as anthracnose, gray mold (Botrytis), and leather rot can become systemic problems in strawberry plantings once established. All three fungal diseases are soil-borne and once in fields can be difficult to manage over the lifetime of the planting.
The use of mulch (matted rows) to prevent/reduce soil splashing and keeping fruit from coming into direct contact with the soil surface can be beneficial in organic production systems where conventional fungicides cannot be used. Use of long crop rotations and staying away from areas of the farm with known instances of any of these pathogens is also important. Remember that same species of Colletotrichum that causes fruit rot in pepper and other crops can also infect strawberry.
May 3, 2015 Andy Wyenandt
Vegetable Disease Briefs – 5/3/15
Basil downy mildew has been found in potted greenhouse-grown basil. All growers producing basil should scout on a regular basis. Basil downy mildew is seed-borne and can cause significant losses.
Late blight has been found in FL and CA. To track the movement of Late blight in the US please visit USAblight.
Cucurbit downy mildew has been found on yellow summer squash, acorn, cucumber, and giant pumpkin in FL and on watermelon in TX. To track to progress of cucurbit downy mildew in the US please visit the downy mildew forecasting website at NCSU.
May 3, 2015 Andy Wyenandt
Vegetable Disease Update – 5/3/15
Cabbage
Damping-off – To help control losses due to damping-off pathogens apply Ridomil Gold (mefenoxam, FRAC code 4) at 1 to 2 pt/A, MetaStar (metalaxyl, 4) see label, or azoxystrobin at 0.40 to 0.80 fl oz 2.08SC/1000 row ft (for Rhizoctonia only), or Ridomil Gold at 1.0 to 2.0 pt/A 4SL plus azoxystrobin at 0.40 to 0.80 fl oz 2.08SC/1000 row ft. in a band up to 7 in. after seeding. To help control damping-off pathogens in Collards and Kale only: Apply Uniform (mefenoxam + azoxystrobin, 4 + 11) at 0.34 fl oz 3.66SE/1000 ft row. For more information please see 2015 New Jersey Commercial Vegetable Production Recommendations Guide. [Read more…]
