Archives for May 2015

May 5, 2015

Cranberry IPM: Sparganothis Fruitworm Degree-Day Benchmarks Provide Key Treatment Timings

Degree-day benchmarks indicate discrete biological events in the development of insect pests. For the Sparganothis fruitworm, recent studies conducted by Dr. Shawn Steffan (USDA-ARS/University of Wisconsin-Madison), Annie Deutsch (University of Wisconsin-Madison), and Cesar Rodriguez-Saona (Rutgers University) have isolated the key development events and linked them to degree-day (DD) accumulations. These degree-day accumulations can improve treatment timings for cranberry IPM programs in spring and summer.

Sparganothis adult

Sparganothis adult

Sparganothis larva

Sparganothis larva

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Filed Under: Cranberry
May 4, 2015

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

Infections can often start in production operations and come in on infected bare root transplants or cuttings. Symptoms on leaves include initial small, irregular water-soaked lesions (Fig. 1).
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Filed Under: Organic Production, Vegetable Crops Tagged With: ,
May 4, 2015

Strawberry Fruit Rots 2015

Anthracnose fruit rot of strawberry

Anthracnose Fruit Rot of Strawberry

Fruit rots in strawberry can cause significant losses if not recognized early and controlled. The use of good cultural practices such as: keeping fields weed-free and promoting good drainage; long crop rotations, and preventative fungicide applications are critical.

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.

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Filed Under: Organic Production, Vegetable Crops Tagged With:
May 3, 2015

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.

Filed Under: Vegetable Crops
May 3, 2015

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…]

Filed Under: Vegetable Crops
May 2, 2015

Fire Blight Alert

The Cougar Blight model over at NEWA is predicting a high risk of fire blight for this coming week, due to the coming hot weather and high humidity along with a chance of showers.

Currently May 5-9 looks like a high risk period for infection. Growers should apply antibiotic to any apple or pear blocks with open blossoms prior to any risk of infection. Streptomycin and oxytetracycline formulations are generally thought to provide 1-2 days protection and possible 24 hours back action. A predication of high risk over a 4 day period may require 2 applications 2 days apart, especially if there is rainfall, and/or the orchard is not yet at full bloom. Follow the label rates. 24 ozs. of strep/acre should suffice. Check your local conditions using NEWA and check back daily as the prediction may change.

Filed Under: Tree Fruit