Soil Temperatures

Soil temperatures have been steadily warming since late March at Hort Farm No. 2 (North Brunswick). Temperatures consistently ran above 50 degree Fahrenheit in early April, and between 50 and 60 degrees from 10 to 27 April.

May 1st was the fifth consecutive day of the maximum soil temperature reaching at least 65 degrees. Thus, soil temperatures are essentially entering into an ‘ideal’ period for the growth of cool-season turfgrasses.

Those experienced with managing summer patch may recall that 5 consecutive days with a soil temperature maximum of 65 degrees is the threshold for initiating a preventive summer patch control program. Isn’t it ironic that ideal growth of the fungus that causes summer patch is synchronized with ideal growth temperatures for cool-season turfgrasses.

Damage from summer patch disease, however, typically is not seen until later in the summer when heat and drought stresses make it challenging for plants with a compromised root system to survive.

summer patch disease on hard fescue

Severe summer patch disease on hard fesuce at Hort Farm No. 2 in July 2013.

Tough Year for Summer Patch Disease

I have seen as much disease damage on turf this summer as any year since I began living and working in New Jersey (1991).

summer patch disease on hard fescue

Severe summer patch disease on hard fesuce at Hort Farm No. 2 in July 2013.

The hot humid weather has been ideal for summer patch and brown patch diseases.

Summer patch disease is caused by a root infecting pathogen, Magnaporthe poae. Wet weather combined with high air (soil) temperatures are thought to be very conducive to the development of summer patch disease.

I have observed more damage from summer patch disease on hard fescue turf than Kentucky bluegrass this year. This is likely due to the fact that more people are growing varieties of Kentucky bluegrass with better tolerance to this disease than was the case 20 or more years ago.

The Rutgers turfgrass breeding program is working on improving the tolerance of hard fescue to summer patch disease.

There are some cultural techniques that [Read more…]