Despite the layer of spring snow last weekend, the growing season will be in full swing in just a few weeks. As you inspect the buds breaking on each plant, take a close look at the foliage, too. Fungi and bacteria could be hiding there. Here are some problems to watch for, along with some suggestions on how to fight them.
●Anthracnose: Irregular tan or brown spots on leaves, especially along major veins, could be Anthracnose blight. It usually shows up in the spring when there is a lot of moisture on plants. Anthracnose will deform and twist the leaves as they grow. (Twisted leaves can also be caused by frost or herbicides.) What to do: Prune heavily affected branches and thin the plants to allow for more air circulation. That will help the foliage dry out and curb growth of the fungus. Rake up affected leaves and burn them. Keep the plant fertilized so it will grow fresh, healthy leaves. Fungicides are available, but usually good housekeeping around affected plants will get rid of anthracnose.
●Powdery mildew: This nonlethal white or gray powdery fungus is found on plants including lilacs, oaks, zinnias, chrysanthemums, roses, flowering dogwood trees, and crabapple trees. Ohio State University scientists say new shoots could be stunted and leaves may twist. What to do: Keep affected plants in a sunny spot with lots of air circulation to deter fungus growth. Good housekeeping practices around the base of the tree will keep powdery mildew from returning.
●Underground problems: Sometimes when a plant is stressed out, its foliage turns yellow, indicating a problem in the root system. Commonly known as root and crown disease, its symptoms may include smaller-than-normal leaves or yellowing between major veins of leaves. (Sometimes spider mites will also cause leaves to discolor because they feed on the moisture from the foliage.) What to do: Because it is an underground problem, it may be linked to soil nutrition. Test the soil around the affected plant and have a soil scientist guide you on what the soil is missing. Sometimes affected plants are too wet. If that's the case, look for ways to improve drainage. Another possibility is from underground pests. Dig down around the roots and check for insect or larval damage.
●Verticillium wilt: Some bacteria and fungi are just part of gardening. Healthy plants can easily shrug them off and will survive. But other types can be more aggressive and should be taken seriously. Verticillium wilt, caused by a fungus, is one of those. Wilting foliage may start on just one limb, and within a season, an entire side of a tree could turn yellow, then wilt away. The soil has been infected with this fungus and any plants in that soil could be affected. What to do: If you suspect a plant has been infected with wilt, call a local arborist or extension office to help diagnose the problem and give the best solution.
A free Plant Healthcare Workshop takes place from noon to 4 p.m. Saturday at Ottawa Park, 2201 Kenwood Blvd., between Douglas Road and Upton Avenue, across from Toledo Hospital. Get information on identifying and felling trees, pruning plants, and identifying invasive weeds and pests. Special sessions for children also are planned. The workshop is sponsored by the Lucas County Extension office, area Soil and Water Conservation districts, the Ohio Department of Natural Resources, and the city of Toledo's Urban Forestry Commission. Information and to register: 419-578-6783.
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