Use fungicide as chemical treatment for lawn circles
Q : Last year in midJune, I started to notice circular dead areas in my lawn. I thought they were grubs, so I put on grub killer and they seemed to not spread. This year at the same time, more dead circles appeared in the lawn.
I called a company and they say it is a fungus and that they can put on an expensive treatment that isn’t guaranteed to help the spots that are already dead, but should prevent it from spreading. They have mentioned that I would need this expensive treatment yearly to prevent the spreading of the fungus. Is there anything I can do to fix the spots that are already dead? What can be done to prevent the fungus from spreading without doing yearly $250 treatments?
A : First, grubs are not organized enough to make circular spots in the lawn. By making a better diagnosis last year the spots may not be as large or numerous this year.
The infection from a fungus starts at a single location and often spreads in all directions from there to form the circles. As the weather conditions change to being less hospitable to the disease organism, the infection will stop spreading.
Sometimes, just the leaves are infected and as the infection spreads, the center area regrows forming a circular donut ring of dead grass. At other times, the fungus kills the whole area.
A fungicide is the proper chemical treatment, but the number of necessary sprays can make it costly. Other treatments also may help prevent the fungus from growing and spreading that are less costly.
If the affected areas are completely dead, you will need to replace the grass with sod or seed. Seeding the entire lawn with disease-resistant grass varieties could help reduce or maybe prevent future outbreaks. Find out what resistant grass varieties are recommended for your area by checking with your local state extension service people.
Most lawn disease fungi need high humidity for several hours before they can infect a grass plant. You can’t prevent rain at night, but you can apply irrigation water starting in the early morning, so it can dry off as the sun comes up rather than in the evening. Evening watering keeps the grass wet overnight, allowing the fungi to grow.
Can any shrubs or trees be pruned to allow more air circulation? This also will dry out the lawn faster. You may notice large fans near golf greens in wooded areas. The fan helps dry the grass after irrigation water is applied.
In northern states, don’t apply fertilizer too late in the spring or early summer. It causes grass to continue growing when the weather is too hot and the grass should be going dormant in the heat. Q : My prized hosta has holes all over the leaves. I think snails or slugs are doing it, because I have found a few. Is it trashed until next year? I’ve had this plant for five years and it’s been doing beautifully until now.
A : Unfortunately, there is nothing you can do about the old leaves that are damaged. You might get some new growth from the plant because it might drop old leaves that are very damaged. You can help the plant by giving it some fertilizer with a higher first number (nitrogen), but of course, don’t overdo it, just follow the label directions. Don’t wait too much longer in the season to fertilize, because promoting late season leaves might just get frosted off before they mature.