Summer Patch

Summer patch is a disease caused through root infection by the fungus Magnaporthe poae. Of great affection in Poa AnnuaPoa Pratensis and Festucas Finas.

The conditions of occurrence are:

-Night temperatures above 21 degrees Celsius

-High irrigation rates

These are parameters frequently reached in summer. It tends to be more prevalent in mature areas than in more recently sown areas.

Summer is the worst time of the year for the Summer Patch.

Symptoms are patches varying in size from a few to several centimetres in diameter. Initially the affected plants wilt, turning greyish-green with white foliar bands. These plants eventually die and leave patches in the form of brown rings and arches. Roots and crowns rot and become necrotic.

Agronomic management involves improving the root system, through aeration, proper irrigation management (avoiding excessive moisture or hydric stress) and proper management of the thatchas well as increasing cutting height during periods of stress. Reseeding with more resistant cultivars such as Agrostis can also help management.

Chemical control involves DMI fungicides such as propiconazole, triadimefon, myclobutanil and fenarimol, as well as strobirulins such as azoxystrobin. Methylthiophanate is also recommended. Broth doses should be high enough to incorporate the active matter into the soil profile.

The time of implementation should be when the soil temperature remains above 20 degrees Celsius, in the first few centimetres of the soil profile, for more than 3 days in a row.