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DALY: Answers about mushrooms, moss, and spots on tree leaves

The Extension office receives a multitude of calls from residents who have questions on a variety of issues of concern to them. Frequently, we receive multiple calls inquiring on how to solve the same or similar issues. Periodically this column will address some of the most common questions asked and provide answers to them that will help readers who may also be dealing with these issues.

Question: Recently, a large numbers of mushrooms and puffballs have appeared throughout my lawn and garden. I am concerned that they may be poisonous, and what can I do to keep them from coming back.

— Peggy in Snellville

Answer: Mushrooms and puffballs are the reproductive structures many species of fungi that inhabit the soil, which is similar to the flower and fruits on plants. They release spores from which new fungi grow in a similar manner to seeds on plants. The fungi are saprophytic meaning they feed on dead and decaying organic matter. They are not harmful to people unless eaten. Some may be edible, but many are not. Many times the good mushroom closely resembles poisonous ones, and they should never be eaten under any circumstances. There is no way to keep mushrooms from growing, and no chemicals exist that will control them. If they become bothersome, you can remove them and dispose of or mow over them in the lawn. They will disappear in a few days.

Q: In my bermudagrass lawn, I have noticed moss growing in some areas. How can I control the moss? Are there any chemicals that will get rid of the moss?

— Joe in Suwanee

A: Several environmental and cultural conditions promote the growth of moss. It prefers sites with shade, and bermudagrass suffers when it does not receive enough sunlight. In lawns that have poor drainage and stay wet for prolonged periods, conditions are favorable for moss growth. Soil compaction and acidic soils can also cause moss to flourish.

If the area of your lawn is too shady for bermudagrass, replace with a shade tolerant groundcover, such as liriope. Another option is converting the lawn to another turfgrass that is more shade tolerant such as tall fescue or zoysia. If the areas drain poorly, consider ways to improve drainage such as altering the flow of water or installing a French drain.

For residential lawns, use a hollow tine aerator every two to three years to break up compacted soils that will allow for improved air and water exchange. Have the soil tested through Gwinnett County Extension, and if too acidic, apply lime according to the recommended amounts on the soil test report.

Q: A large white oak tree, roughly 60 feet tall and a trunk that is three feet in diameter, has developed small brown spots on the leaves causing them to turn yellow and fall. What should I spray the tree to stop this problem from occurring?

— Jack in Lilburn

A: What you are observing are leaf spots caused by one of many species of fungi, and the wet conditions recently are conducive to this. The spots and leaves falling will not harm the tree. It can sustain losing some of its leaves and still continue to thrive. Spraying the tree with a fungicide is not practical or economical. Just clean up and dispose of any leaves that have fallen to the ground.

Timothy Daly is the Agricultural and Natural Resources Extension Agent with Gwinnett County Extension. He can be contacted at 678-377-4010 or tdaly@uga.edu.