A: It seems as if the plants have been attacked by powdery mildew. This is a closely related to rust fungi. Dust reproductive spores of mildew. It takes place in an acidic environment in a temperature range of 60-70 ° F (15 to 21 ° C) with humidity above 50%. The spores float in the air and there is no practical way for consideration out. Instead, try to change the environment so that conditions do not match the needs of mildew. This may require raising the temperature or decreasing the humidity.
There are also several safe and effective ways to control powdery mildew with minerals or organisms.
Most mildicides listed here are fairly new and all are much less harmful than the old chemical formulations. You will not find most of them in your local store or garden store, but are available on the Internet. Many companies that sell there. All these mildicides used in edible products or herbs. Some are naturally occurring organisms and are exempt from registration. Others are registered for use in vegetable crops and are considered the "caution" category, the category of registered mildicides least dangerous.
AQ10: AQ10 uses a completely new method for combating mildew, a bio-fungicide. The active ingredient, Ampelomyces quisqualis is a fungus that parasitizes powdery mildew body. Provides control over a long period of time.
Cinnamite: Cinnamite a cinnamon extract is used as an acaricide, which is also effective as a fungicide. It is very easy to use, effective and has a pleasant smell of cinnamon. Studies show that is not harmful to the marijuana plants.
Copper: Copper ions inactivate some fungal enzyme systems, killing mycellium. Copper has been used for over 100 years, and is effective. Some brands of copper based fungicides is Phyton 27, Dexol copper and DF Kocide Bordeaux Mix. There are many brands available.
Neem Oil: Neem oil is pressed from the nut of the neem tree of India. Protects against mildew and kills by interfering with breathing and collapse of the cell wall. Some manufacturers claim that the plants grow stronger when sprayed with neem oil diluted twice a month. There are many brands available neem oil. Many of them are listed as organic.
Shield Floor: shield containing the microorganism Trichoderma harzianum strain T-22. This organism attacks of fungi and molds. Used as a spray or dip. The organism seeks its food and forms a symbiotic relationship with plant roots, which also protects.
Potassium bicarbonate: potassium bicarbonate and dried collapses mold hyphae. Contact This is a very safe, very effective fungicide. Mold does not develop resistance to it. The potassium in the formula is absorbed by the plant. Two brands are Kaligreen (registered in California) and Armicarb100.
Serenata: The product of fermentation of a bacterium, Bacillus subtilis, which inhibits cell growth of fungi and bacteria. It is very effective and easy to spray on or use as a sauce. This is a contact fungicide that kills only areas that are contacted. A wetting agent or spreader increases the total contact.
Sodium bicarbonate (baking soda) Baking soda leaves an alkaline residue on the leaves. Sodium collapses the cell wall of mold powder in the alkaline environment discourages growth. Plants have a limited tolerance of sodium, so the residue should be washed before more is applied. Used in the rate of 1 / 2 teaspoon per quart of water with a wetting agent.
Sulfur: sulfur Elememtal interferes with cellular respiration mold. It has been used as a fungicide for over 100 years. There are little packages available in the bakery sections of supermarkets.
These new resources will make it much easier to deal with powdery mildew. They are non-toxic and eliminate the problem fairly easily.
Powdery Mildew Prevention & Erradication Products: