June 4, 2013

The wet weather has resulted in an increase in slime mold showing up on lawns.  This problem is caused by primitive fungi that exist primarily as saprophytes (organisms that live on dead organic material) and use living grass plants for support.  Fungi in the genera Muctlaga and Physarium are usually the causal agents.  They can take on a wide variety forms.  Sometimes people describe it as something that looks like the dog threw up on the lawn.  Other times it looks like gray slime on the leaves.  Then, it can take on some truly strange appearances that you would not associate with a fungi.

The fungi can be washed off with a hose.  It will usually go away after the wet dreary weather changes.   We generally do not recommend fungicides for this problem.

Larry Ginger of American Lawn Care sent in the first picture earlier this week.  This is typical of the way slime molds generally appear in wet weather.

Slime Mold

 Here is a close up of some slime mold from the research station.


Here is one from my own lawn that looks like the dog threw up.



Here is the most unusual one that I have seen.  This came from a lawn in Iowa.



Nick Christians Professor

Nick Christians, Ph.D. – University professor of turfgrass management, Iowa State University, Department of Horticulture, Ames, IA, and adjunct faculty, Department of Agronomy, Iowa State University, Ames, IA. Dr. Christians received his B.S. from the Colorado State University ...