Hi Gerry,

 Earlier this week Phil came out to treat my lawn for grub prevention.  I had the opportunity to talk to him about some dead spots in my lawn.  I thought it was due to the drought even though I had been watering.  He told me that the grass circles with dead rings around them were indicative of a fungus. Phil suggested overseeding using a black loam and a disease resistant (ie. endophyte enhanced grass seed) with a high rye concentration. He said I could not get rid of the fungus but this would mask it.

 I went to a Garden centre to see if they had this grass seed and the horticulturist questioned why I would want to mask the problem rather than get rid of the fungus with a sulfur compound.  They also did not have a endophyte enhanced grass seed.

 I have two questions for you.

 1. Why did Phil tell me to mask the problem rather than use sulfur?

2. Where do I get endophyte enhanced grass seed?

I also bought some bags of black top soil when I will overseed. Is this fine instead of black loam?

 I would appreciate your opinion before I start to treat the lawn.

Thank you, Andy

Hi Andy

The circle dead spots are caused by Necrotic Ring Spot (NRS) Disease. 

Fungicides are rarely of value in treating this disease. Sulphur is used on many fungus diseases. It has not been shown to be very effective in treatment of NRS. It usually is not expensive at the garden centre, so no harm in trying.

Phil is right about the perennial rye grass - in that perennial ryes are much more resistant to the disease than Kentucky blue grass.

Phil was momentarily mixed up about the endophyte. Endophytic perennial rye is used to reduce chinch bug damage.

While using endophytic perennial ryes will help with chinch bugs, it doesn't make a difference with NRS.

 The grass seed we use contains perennial rye varieties that are endophytic. If you prefer to use that type let me know and we will be happy to sell you some.

Gerry