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Powdery Mildew—Organic Control

June 30, 2011 - GrowOrganic
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Welcome to the Powdery Mildew edition of Stump the Gardening Stars. See how much you know about one of our least favorite fungi. True or false? 1.  Overhead watering increases powdery mildew. 2.  Powdery mildew is worst in humid climates. 3.  Shade is the happiest home for powdery mildew. 4.  The powdery mildew on your cucumbers is the same as the one on your tomatoes. 5.  Powdery mildew always shows up as white powder on plant leaves or fruit. Answers: 1.  False 2. …
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Video Transcript
Hi I'm Tricia a California organic gardener. It's officially summer and I'm starting to see some really good results from all the work I've put in this spring and then uh oh out pops the powdery mildew.

Powdery mildew effects every type of plant from roses and lawns to forest trees and vineyards. It is most prevalent in more mediterranean climates like California. All it needs to grow is temperatures between sixty five and eighty degrees and high relative humidity. The first line of defense is a healthy plant I'm going to give my plants some compost tea to help them stay healthy. The second line of defense is to plant varieties that are resistant to powdery mildew like these contender beans or the sumpter cucumber. Avoid planting in too much shade and don't overcrowd your plants that'll really contribute to powdery mildew. Sometimes resistant varieties do not exist or they don't fit your needs for example grape vines are often effected by powdery mildew. My grape vines are at risk of getting powdery mildew if they don't get their summer pruning soon. The summer pruning will increase airflow and help prevent the mildew. There are a variety of organic fungicides and oils that can help prevent or treat powdery mildew for example sulfurs are an inexpensive and effective way to control the disease. They need to be sprayed before symptoms of powdery mildew appear. Be sure and read the label really carefully because sulfurs can actually harm some plants for example apricots. Serenade is a biological fungicide that will treat powdery mildew. Serenade contains a bacteria that attacks the powdery mildew fungus. Oils are another great option to control powdery mildew because most of them will eradicate it and prevent it from happening. Neem oil and other horticultural oils are good non-toxic choices. Read the labels carefully though generally speaking oils shouldn't be sprayed for at least two weeks after sulfur applications. I hope you never have to deal with powdery mildew but if your concerned that you might have it on some of your plants these pest ID cards are great because it'll help you ID powdery mildew as well as other diseases. So thanks for joining and grow organic for life

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Solutions: Powdery Mildew

Categories: Grape Vines, Wine Grape Vine, Table Grape Vine, Organic Pest Control, Horticultural Oil, Organic Fungicide

Krystal Frost Says:
Jul 1st, 2011 at 12:22 pm

As an organic grower on the west coast of the Pacific coast of Mexico, powdery miildew is a constant problem regardless of the season due to the average temp 80 degrees and humidity from the jungles. Those of us planting out of the U.S. do not have access to your recommended products,  However, we use 1 part raw milk to 9 parts water, sprayed every 6-8 days not only gets rid of the white mildew, it also prevents further development.  We spray for a 4 week term, twice a year.

Rich Ever Says:
Jul 5th, 2011 at 7:00 pm

I spray an organic oil on my apple trees in the dormant season as well as summer to protect against powerdy mildew.
Although I purchase some from you, I was wondering if purchasing gallons of either vegetable, corn, canola, or soybean oil purchased locally would do the same as the Stylet or other OMRI listed oils I currently purchase?

Charlotte from Peaceful Valley Says:
Jul 7th, 2011 at 11:19 am

Krystal, Thanks for sharing your tip!

Charlotte from Peaceful Valley Says:
Jul 7th, 2011 at 11:47 am

Rich, Stylet contains parafinnic oil, Saf T Side has petroleum oil, and Organocide is a combination of fish and sesame oil. It’s important to use the horticultural oil products only for their labeled purposes.

uncokouida Says:
Dec 29th, 2011 at 1:25 pm

I’m sure the best for you to your friends   for more detail

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