Managing Downy Mildew & Powdery Mildew

2016 Summer
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Printable PDF (1.2M)

Downy Mildew on cantaloupes and winter squash (butter-nuts and acorn) has been confirmed throughout much of the Northern United States.  In addition, we are now in the typical summer weather cycle of thunderstorms followed by high humidity that encourages Powdery Mildew on cucurbits and eventually field and tunnel peppers and tomatoes.  Managing these two very different diseases requires careful attention and timely applications of fungicides.

One new tool that ISP Technologies has brought to growers are silicon heavy specialty nutrinets.  Silicon is not considered a necessary plant nutrient like nitrogen, phosphorus, potassium, copper, iron, calcium, magnesium…, but is highly important in creating strong plants that resist lodging.  In addition, research done at Rutgers University indicates that increasing plant available silicon directly improves the management of plant diseases such as Powdery Mildew.  Silicon in the nutrient stream makes its way to plant cell walls where it makes them better able to resist germinating fungal spores ability to penetrate into plant tissue and cause disease.  Si has also been noted to assist plants in resisting insect damage and cope with environmental stresses such as high salts.

ISP Technologies has two products that make the application just another part of plant nutrition and pest management.  SiMag58 is ideal when dealing with magnesium deficiencies which are very common in fruiting plants such as tomatoes, peppers, cantaloupes, and watermelons.  It’s got highly available EDTA chelated magnesium along with the maximum dose of potassium silicate.  The rate for this material is 1-2 teaspoons per gallon foliarly every 7-10 days or 8-16oz per acre per week through the drip.  SiGuard is 84% available silicon so it is primary designed to boost pest management.  Apply SiGuard at 1tsp. per gallon foliarly.

Both materials should be compatible with your current spray program and can be tank mixed with other pest management materials.  Always do a jar test prior to using any new tank mix.

Basic Downy Mildew (DM) management program:

Either regalia, or chlorothalonil (Bravo), or Mancozeb, plus a DM specific material such as: Ranman, Previcur Flex, Zampro, Tanos, Curzate, Zing (already has chlorothalonil), Forum, Gavel, Presidio or Ariston, plus SiGuard or SiMag58.

Basic Powdery Mildew (PM) management program:

Either Regalia, or chlorothalonil, plus a PM specific material such as: Quintec, Torino, Proline, Procure, Rally, tebuconazole, Inspire Super, or Aprovia Top, plus SiGuard or SiMag58.

Important note: With all of the recommendations above, read the label thoroughly before making any application.  Specific varieties may be sensitive to certain fungicides and any new tank mix should be both jar tested and applied to a small portion of the field prior to complete crop application.

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