Metro-East Living

Spot anthracnose can kill dogwood trees

By Charles Giedeman

These dogwood leaves show the results of dogwood spot anthracnose disease.
These dogwood leaves show the results of dogwood spot anthracnose disease.

Q: Any ideas what is going on with my dogwood tree? It is about 20 years old, had beautiful blooms this spring, but now the leaves are withering.

E.B. of Caseyville

A: Your tree is suffering from dogwood spot anthracnose (Elsinoe corni or Botryttis cinerea) disease. Your dogwood bloomed beautifully this spring and the flower petals picked up the disease. As the petals fell, they spread the disease to the leaves of your dogwood. These little purple areas on the leaf later fall apart and leave holes. There easily can be more 100 infections on the leaf at one time. The spores produced can linger until next spring, then infect the floral buds on the tree.

The rain that fell when the tree was in flower gave the perfect condition for this disease to attack. Try to remove all faded flowers and infected leaves as possible. Next spring, if the weather is extremely wet or humid, you will need to spray with a fungicide containing benomyl, zineb, maneb or mancozeb as the active ingredient. Spray when the dogwood’s flowers are early in the bloom stage or just opening. Over time, this disease can kill your tree because the disease moves through the leaves into the stems, then into larger branches. If it enters the trunk, your tree could die.

Q: I want to encourage predator insects to my garden but how do I do this without using insecticides?

K. L. of Collinsville

A: In a nearby bed plant species that will attract predator insects such as parasitic wasps and ladybugs. These include plants in the mint family, Queen Anne’s lace, catmint and yarrow. Most gardeners consider these plants weeds, but they can serve as host plants, keeping the predator insects around and developing throughout the growing season.

Q: We have a strawberry bed and the birds are there at daybreak to feed on the berries. How do we keep the birds away?

M. D. of Okawville

A: Start by hanging some monofilament fishing line over the strawberry plants, then attach aluminum pie pans, aluminum-colored ribbon and some seashells together to make noise in the wind to keep them away. Later you may need to cover the rows of strawberry plants with 3/4-inch plastic mesh placed over hoops or branches that are anchored to the ground with stones or bricks. Remove the netting when you are picking the strawberries and cover up the rows again when you are finished picking for that day. If one bird gets tangled in the netting, the rest of the birds will stay away for some time without any problems.

Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Editor Maureen Houston, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to mhouston@bnd.com.

Do it now

  • Keep the weeds under control in the garden and flower beds. With all the rain we have experienced these past few weeks, weed seeds have germinated very well. Remember every time you disturb the soil by hoeing or pulling the weeds, you actually help more weed seeds germinate. A mulch will do a better job preventing weeds from getting started.
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