Powdery mildew is a plant disease that is one of the easiest to identify and is the most common. If you have a plant afflicted with powdery mildew, you’ll know about the white or gray powder-like coating that will be on the plant in spots or patches. It is worse in areas that are warm and dry.
Basic Powdery Mildew Facts
- It is a fungus that goes from white spots and patches to yellow-brown and then to black.
- While most common on the tops of the leaves, it can also be found on the fruit, buds, flowers, and stems.
- Powdery mildew can be worse if the plant is older and in poorer health.
- It is the worst when there is 90 percent humidity and poor air circulation.
- There are some plants that have been grown to be resistant to the fungi.
How to Rid a Plant of Powdery Mildew
Chemically, this can be as easy as the fungicides that have potassium bicarbonate, neem oil, sulfur, or triforine in them. They will need to be put on the plants in seven to fourteen day intervals. Naturally, you can use baking soda and a lightweight horticultural oil together. Try a tablespoon of baking soda mixed in with 2.5 tablespoons of Sunspray oil. Mix that into a gallon of water. While experimental, some are reporting good results with this type of mixture.
Tips and Tricks for Powdery Mildew
- Always remember not to compost any plant materials that have powdery mildew on them. The temperature in a compost pile does not get high enough to kill the fungus, and you will just pass the disease on to whatever plants you use the compost on.
- Pruning your plants well can increase the amount of air circulation they receive. This can help reduce the chances of infection.
- When you water your plants, water from underneath the plant instead of overhead. Overhead watering can lead to higher humidity and increase the likelihood of powdery mildew.
- Don’t use nitrogen fertilizer after mid-summer. Using this type in the later months can increase the chances of new growth, which is more prone to infection from the powdery mildew fungi.
- Try some of the more resistant varieties of plants to lessen the chances of getting the infection in your garden or flower bed. Some of these include the Adirondack crabapple, the Blue Stocking bee balm, The Cherokee Brave dogwood, the Hopi crape myrtle, The Prairie fire crab apple, the Natchez crape myrtle, and the Miss Kim lilac plants.
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