St Augustine grass black spots

I have St Augustine grass in my front yard. I have several small patches about 4 inches in circumference that are black. When I put my hand on the black spots, it comes off on my fingers. It makes a stain on my fingers but I can wash it off. I am trying to figure out if it is a fungus. To complicate this, a company just sprayed new asphalt on my street. I am not sure if this is a fungus. The asphalt company claims that it did not come from their trucks. The black spots go up about 20 feet in my yard. What do you think that it is?

Did the black happen all of a sudden the day the asphalt was put down, or did it develop at a different time or has it spread or changed at all? If it came on the same day as the asphalt and the spots haven't changed in size/shape at all then I think that's what it is, but if it had started before that or the spots have been changing size/shape then it's most likely fungus. You might also try smelling your hands after you've touched the black stuff--I'm not sure what it would smell like if it's fungus, but if it's ashpalt then it'll probably smell like tar/oil, definitely not a "natural" sort of smell.

I am not sure if the black spots which were 4" in diameter (not cirmcumference as I mistakenly wrote last time) came up in a day but they did come up very quickly - probably in less than a week. I was too busy to look at the yard much on the week of July 4th. This afternoon, it appears that it is spreading and even came up on the bahia grass. It just that it is hard to tell how much that it is getting worse. Some fungus on St Augustine grass make the grass yellow or brown (brown patch) but this is black and it comes off on my fingers when I touch it - much like ink from a toner cartridge when you replace it in a copy machine. I put a fungacide on it tonight. I have something similar in the back yard but it is about 5 feet by 5 feet and I have never noticed it come off on my hand. (please note that I also have some yellowing in my grass in the front yard. I thought that it was from lack of water in the spring but it may be a fungus as well). I will ask again if anyone has experience with a fungus that is black going mainly on St Augustine grass.

Well, if it's spreading then it sounds to me like it's probably a fungus of some sort rather than the asphalt guys messing up. You might try taking some to your county extension office and see if they can help you if nobody here has any ideas. I don't have a lawn and don't live in a climate that even remotely resembles yours so unfortunately I don't have any ideas on what it could be.

Riles,

Does this sound like the problem you have?

http://www.plantanswers.com/root_rot_fungus.htm

Thanks. Actually I had already that site after doing a search on this. It does sound somewhat similar. It's just that I have not seen a comparable photo to what I have and I have not read anywhere of the residue coming off like having ink on one's hand....What's also odd is that I had just put down chinch bug killer a few weeks ago but the chinch bugs seem to be coming back in one portion of my front yard. We are sort of out in the country and a neighbor a few houses down had almost his entire front yard wiped out by chinch bugs. Anyone know of a natural chinch bug killer that would work down in Florida on St Augustine grass?

This message was edited Jul 11, 2007 9:23 PM

I knew it didn't answer the question of the black stuff, but I couldn't find anywhere that black-ink condition was mentioned in connection with St. Augustine or any other grass. Weird. So, if that TARR stuff is not it, I'm out of suggestions. Can you take a sample in and ask your county agent or your local ag college?

I grew up in So. CA with St. Augustine grass. It was known to be totally pest-free in those days -- 1950s-1970s -- I'm older than I look. LOL. Of course, it was the old-fashioned St. Augustine. There was no such thing then as different types or cultivars -- just St. Augustine. I'm wondering if the development of these new-fangled types is the reason for the problems now. Hmmm.

I did find this info on getting rid of chinch bugs:
Chinch bugs like hot, dry, sunny lawns, so regular watering will reduce if not completely eliminate the chinch bug population. A heavy infestation can be controlled by spraying your lawn with insecticidal soap every 2 or 3 days for a week or two. Pyrethrum or sabadilla dust are also effective, as is Neem®. If you decide to go the inorganic route, Dursban® is the pesticide of choice.

At least they list some non-lethal things to try first. I hate to use commerical pesticides. So far, the few times I've broken down and actually tried them, they haven't worked anyway.

Good luck. I wish I could help more.

Karen