There's Powder on My Flower: Dealing with Powdery Mildew by Carrie P. Williams
Have you ever come home from work only to wonder why in the world your plants look as if someone had dumped talcum powder all over them? After interrogating your spouse and kids to no avail, you go back out to your plants only to realize the mysterious isn't powder at all. Instead, it seems more like a growth on the leaves themselves, kind of like . . . mildew. Yes, your plants have run into a battle with powdery mildew. What can you do to help your plants win the war?
First, we must know exactly what powdery mildew is. Though there are different types of mildews out there, all are a fungus that resemble a dust of light grey to white powder on plant leaves and stems. It will form especially on younger leaves which are more tender and less immune to infection.
At first, powdery mildew only damages the plant aesthetically; that is, your plant just won't look as good. But if you leave the fungus to it's own devices, it will soon cause stunting and distortion of leaves, buds, growing tips, and fruits; leaves will yellow and then drop; and you will see a general decline of growth and vigor of the plant. Powdery mildew is a fungus that should be taken care of when spotted.
Though caused by a fungus, the formation of powdery mildew can be aided by the surrounding environment. This fungus prefers times of the year where cool nights come after warm days. It also forms where there is insufficient light for a plant to thrive. Plants that are stressed by environmental conditions have less energy to ward off offending pests. Powdery mildew also will grow in an area with poor air circulation and increased humidity. Does this remind you of another area where mildew will form?
When given the right conditions, powdery mildew can form on most plants. However, there are some plant varieties that contract the fungus more than others. Some plants to watch out for are crape myrtles, euonymous, roses, zinnias, grapes, tomatoes, apple trees, maples, peach trees, sycamores, clematis, and hydrangea. But wait, don't go pulling these plants out of your garden yet! There are numerous things you can do to help prevent and control the spread of powdery mildew.
Prevention almost always is easier than control of an existing problem. There are many things you can do to prevent the introduction of powdery mildew into your landscape. In the landscape planning stage, you can opt to plant only resistant varieties of ornamental plants, which are less likely to contract the fungus. When watering your plants, take care to keep most of the water off of the leaves to prevent humidity around the plant. Also, make frequent inspections of your plants. When caught early, removing powdery mildew from your garden can be done rather easily.
Once spotted, the sooner you begin to control your powdery mildew outbreak, the easier it will be. First, reduce the amount of nitrogen in your fertilizer applications. This will keep the plant from producing too much new green tissue which is like a delicacy to the fungus. Also, pick off and destroy any plant part that is infested with the mildew. You don't want to compost this material or you could spread the fungus to your other plants. Lastly, look into some horticultural or fungicide sprays for your plant. Look at the labels to find if it will be right for your plant; some fungicides are more target-specific than others. Don't forget to read the entire label, including warnings, before applying any pesticide.
By correctly identifying, preventing, and controlling powdery mildew in your landscape, you can spend less time fretting about the lagging health of your plants and more time enjoying the beauty of your landscape. Instead of that dull, whitish cast among your plants, they will be shining with a healthy, bright green luster. Lastly, not only will your family also appreciate the lovely greenery, they will be relieved they will never again be the accused parties of a conspired talcum powder plot.
Carrie P. Williams is a professional landscape designer with Turf Tamer, Inc. She has written many informative landscaping articles for Turf Tamer's Tip of the Week program. Want to learn more landscaping tips and tricks? Go to http://www.turftamerinc.com to find more tips.