Weeds, disease, and mosquito spray dead spot

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.  

After mentioning something a couple weeks ago about how the turf might quickly show signs of stress this summer when the weather dried out, I decided to take last week off from writing as my turf crystal ball gazing seems to be a little cloudy from all the rain! With respect to home lawns, 2009 is turning out to be one of the all time best that I’ve experienced in Michigan for having a great looking lawn. The constant rainfall and cool temperatures are ideal for growing our cool season lawns. The biggest challenges in maintaining lawns this year is keeping up on mowing, providing adequate fertilizer amounts and dealing with weeds. Just as the turf is favored by the weather, so are numerous weeds. If you combine the abundant turf growth with less than adequate fertilization, there are several weeds that you might find giving you extra fits of frustration this summer. White clover and black medic are two weeds that are often identified with thin or under-fertilized turf areas. In addition to using a broadleaf herbicide to knock them back now while they are flowering, check your fertilizer program to ensure that you’re giving the turf an adequate chance to compete.

Also related to the abundant turf growth and depletion of fertilizer applications, red thread is a disease that you are probably seeing in turf areas. Red thread is often found in areas dominated by fine fescues or perennial ryegrass. Red thread is easily identified by the pinkish-red mycelium that is threadlike and surrounds the leaf blade. In some extreme cases, it might remind you of miniature balls of pink cotton candy. The areas infected by red thread will die and the turf may appear wilted. Fungicide applications are usually not necessary in dealing with red thread; a fertilizer application will often help the turf outgrow the damage.


Whether working in the yard, walking in the park, or playing some golf, the mosquitoes are certainly quite pesky this year. Once the mosquitoes emerge, we start to see mosquito spray dead spot on turfgrass, especially on golf courses where the turf is mowed short. When drenching your legs in your favorite aroma of repellant make sure to do it on pavement not on the turf. Mosquito repellant has a way of killing the turf just like Roundup and leaves some interesting death patterns on turf.

Did you find this article useful?