Monday, April 24, 2017

Large Patch or Brown Patch Fungus - Conditions Are Right

Horticulture Hotline 04/24/17
By Bill Lamson-Scribner

With the cool nights and recent rains, turf fungus seems to be thriving in the Lowcountry.

Large Patch or Brown Patch fungus loves these weather conditions. Temperatures in the high 50’s to low 60’s at night and moisture make conditions real favorable for Large Patch or Brown Patch fungus. We have had plenty of these conditions making the fungus environment perfect for the spread of this disease.

Since it is very difficult to control night time temperatures, you can put your efforts into doing other cultural things to help minimize the disease. Large Patch or Brown Patch fungus likes wet, heavy thatch, improper nutrition, and/or compacted soils.   Culturally you need to manage your irrigation system, raise any low areas, and correct drainage problems.  Reducing thatch, maintaining proper fertility levels, and aerating to alleviate compaction, will also help control Large Patch or Brown Patch fungus.

Certain organic products have shown to increase microorganisms in the soil that compete with plant pathogenic fungus in the soil. At Possum’s we get good feedback from Nature’s Blend, SeaHume, Crab Shell, Corn Gluten, and Cotton Burr Compost. These products are not fungicides; however, people that use them (homeowners and commercial applicators) report back to us that they notice less fungus in the yards that they apply these products.

Since the grass is coming out of dormancy so slow, a systemic control product like T-Methyl and Fame in rotation might be a good idea to get you through the next month or so as long as conditions are favorable for the disease.

Being a soil borne disease, the disease will reoccur in the same areas year after year.  If the base of a leaf blade with Large Patch is moved from one part of the yard to another (lawn mower and not very likely), this can begin a new infection area; however, these are not spores flying through the air.  As a soil borne fungus, if you map the areas that you have the disease, you can concentrate your control efforts (dollars) into a smaller area, putting less control products into the environment.  If your yard is 5,000 sq ft usually you might have a few infected areas which might total approx. 500 ft.  Instead of buying control products to treat 5,000 sq ft, you can concentrate your efforts into the 500 ft (i.e. 10% of your total yard).  If Large Patch was an air borne fungus with spores, you would want to treat the entire yard because air borne fungus spreads a lot quicker than this soil borne fungus.

Always read, understand and follow product label. The product label is a Federal Law.