Powdery mildew is a fungal disease that results in a powdery gray or white coating on the leaves and stems of infected plants. It starts out as a few spores on the leaves, and quickly spreads, eventually yellowing the leaves and causing premature leaf drop.
Damage to Plants:
Besides being unattractive, powdery mildew results in leaf yellowing and droppage, stunted plant growth, distortion of buds, blooms, and fruit, and eventual overall weakening of the plant.
Disease Life Cycle:
Spores overwinter on diseased plant parts, and begin asexual production of new spores once the weather warms. New spores are carried on the wind to other parts of the plant, or to other nearby plants. Spores never stop producing more spores, so if infected leaves are not destroyed, the problem will only get worse.
Treatment and Prevention:
Powdery mildew thrives in temperatures between 60 and 80 degrees. Dry, shady conditions are ideal, as are areas with poor air circulation. Planting disease resistant cultivars and making sure you allow for good air flow are two ways to guard against powdery mildew. Inspect plants regularly during warm, dry conditions, and remove any leaves that show signs of infection. Destroy (do not compost!) infected plant parts. A spray made with baking soda, if applied weekly at the first signs of infection, can protect plants against further damage. Plants that are badly infected should be ripped out and destroyed to prevent the disease from spreading further.
A commercially available organic option is Neem oil, which both treats existing powdery mildew and protects the plant against further infection.
Interestingly enough, the most effective measure in preventing and treating powdery mildew is to spray the foliage of your plants daily with plain water from the hose. Powdery mildew hates water! The only caveat with this method is to be sure you do it early in the day so that the foliage completely dries before cooler evening temperatures arrive, otherwise you may invite other fungal diseases, such as black spot, into your garden.
Powdery mildew is a fungal disease that appears as a dusty gray or white coating on plants. Vegetables such as cucumber, pumpkins, squash and melons; houseplants such as African violet and begonia; and outdoor plants such as phlox, lilac and rose are all susceptible to powdery mildew. Not only is the disease unattractive, but it can distort and stunt a plant’s leaves, buds, tips and fruit. If enough leaves or tissue are affected, the plant may die.
How Powdery Mildew Forms
Wind carries powdery mildew spores. The disease can appear at any time, but it’s more likely to grow rapidly in shady areas, if there is slow or nonexistent air circulation or when the humidity is high. Powdery mildew can reproduce both sexually and asexually.
If you’re planting a susceptible specimen, choose an area with as much sun as the plant can handle. Don’t crowd the plant; make sure there is enough room for air to circulate. Use a slow-release fertilizer; avoid liquid fertilizers that may splash spores back onto the leaves. Water the plants at the root level, not from above. Plant varieties resistant to powdery mildew.
There are major advancements in natural plant oil extract technologies. There is one that has shown tremendously great results., its called No Powdery Mildew™. No Powdery Mildew™ goes to work immediately and on contact with a dual lysis action that attacks powdery mildew spores on contact, while penetrating your plants cell walls giving them added strength and vigor. No Powdery Mildew™ can be used from germination to day of harvest. It can be sprayed under any lights as often as you like. There is no harmful aroma’ or aftertaste to your valuable fruits and vegetables because the natural plant oils inNo Powdery Mildew™ leave a fresh, clean aroma that is safe for humans and pets.
Powdery Mildew starts out as whitish spots that spread quickly until the entire leaf is covered. The white powdery growth is a fungus that with time becomes gray to tan/brown felt like patches. Leaves may become stunted, curled, chlorotic and eventually wither and dry up.
Moderate temperatures and high humidity help develop the disease. The pathogen also favors hot days, cool nights, high humid (85%) conditions and the change of season. Each mildew pathogens is specific to its host, the mildew that attacks gerbera daisy will not spread to cucumbers.
Depending on the severity, spraying it with a baking soda formula is effective as a preventative when applied regularily. For active infections spray daily for a week.
1. Mix 1 TBsp each of baking soda and horticultural oil (dormant oil/vegetable oil) or a few drops of liquid soap to 1 gallon of water. Spray weekly making a new mix each time. It will not elliminate the disease but help control it.
2. Mix 1 tsp baking soda with a few drops of vegetable oil in 1 quart of water. Spray or paint on the leaves. Works on houseplants, cucurbits & roses (balck spot).
Another suggestion is a solution of 1/3 milk and 2/3 water and spray on plants. Use every other day.
I also heard of mixing 1 tbsp of pine sol to 1 gal of water as a mildew spray. Neem Oil is also affectective in controling infections. Use 1 oz.(2 Tbsp) of Neem oil and 1/ 1/2 tsp of dishwashing detergent to one gallon of water. Spray once a week for two weeks.
Use chemical sprays such as Benomyl (systemic fungicide), sulfur/fungicidal soap early in the growing season as a preventative or as soon as symptoms appear. A new organic fungicide that has been making waves is No Powdery Mildew™ which is a natural plant extract formulation that cures, treats and controls powdery mildew outbreaks. Always follow label directions, to make sure the product is approved for specific plants. The combination of Neem and baking soda is the safest control method. Once the disease takes hold, it is difficult to control.
Some cultural preventatives that can be done are to remove the infected leaves, do not crowd the plants, provide good air circulation and keep plants well watered and stress free. Grow resistant plants when available.
Powdery mildew is a common problem in areas that have high humidity. It can affect almost any type of plant, appearing on leaves, flowers, fruits and vegetables. A white or gray powder coats the surface of the plant. If left untreated, it can turn more severe, causing leaves to turn yellow or brown. Many people look to a homemade cure for powdery mildew before turning to fungacides. However, finding a powdery mildew homemade preventer is preferable.
Prevention of powdery mildew
The best way to take care of powdery mildew is by prevention. Be sure to start with healthy plants. One powdery mildew homemade preventer is to simply prune back any dead plant material during the normal pruning time. Do not plant things too close together, to allow ample air circulation around the plants. It is important to not plant in damp shady areas, as that is a prime location for powdery mildew. Another powdery mildew homemade preventer is to avoid using the sprinklers in the evening, so the water doesn’t stand on the leaves too long. The water itself doesn’t cause more mildew, but it allows it to be transported to the other leaves on the plant easier.
Organic removal of powdery mildew
But, when prevention fails, it is a good idea to try organic removal of powdery mildew first. If you have a case of powdery mildew, be sure not to compost the infected plant parts. There are a few options to try when trying a homemade cure for powdery mildew.
One powdery mildew organic remedy is to use dilute solutions of hydrogen peroxide. Spray it on the plants thoroughly about once a week. Organic removal of powdery mildew is always preferable to using harsh chemicals on your plants.
There are even some plants, such as the lilac, that can have the powdery mildew on it and it doesn’t hurt the plant that much. So using a homemade cure for powdery mildew on the hardier plants isn’t necessary.
Another thing to remember is that if one type of plant gets it, that particular strain of powdery mildew won’t transfer to the other types of plants. For example, it won’t go from the roses to the lilacs, just to the other roses.
The best powdery mildew homemade preventer is maintain the proper moisture level, without raising the humidity around the plants too high. This, along with careful annual pruning will go a long way toward keeping your plants healthy and beautiful.
A fungus which appears as a dry powdery bloom on the upper sides of leaves, usually in hot dry conditions. Ornamental Malus and fruiting apple trees are most susceptible to the above species. Other species of powdery mildew effect roses, peas, gooseberries, vines, strawberries, turnips, cucumbers and cereals. Ornamental plants like Chrysanthemums, Michaelmas dasies and Phlox are susceptible.
It survives the winter as mycelia in the buds, affected buds and smaller twigs have a silvery appearance. At bud break in the spring the mycelium emerges and grows on the surface of the young leaves (primary mildew) producing asexual spores which are carried in the air, landing on other leaves and developing into secondary mildew. This growth withdraws moisture and nutrients causing premature leaf drop and if young fruit are affected they develop a rough skin – russeting. Sexual spores may be produced in the autumn, but are not important for over-wintering on apple trees as it survives in the buds. The species which infect herbaceous perennial or annual plants spend the winter as sexual spores, ready to attack the new growth.
The white mycelium of Powdery Mildew on the leaf of a rose.
Cultural control in apples is by winter pruning to remove infected buds and open up the tree for good air flow. Other hygeine considerations are important with strawberries and vegetables, ie. removing leaf debris which could overwinter the spores, and good separation of plants. During dry weather keep plants well watered especially roses growing near walls and containerised fruit trees.