Tuesday, October 21, 2025

Large Patch Fungus

 

                                            Halloween and Large Patch

                                                      Large Large Patch


                                                      Large Patch
                                                      Controls Large Patch

            

Horticulture Hotline 10/21/25

By Bill Lamson-Scribner

 

Wow, we are getting weather that is making it really hard to deal with some of our perennial worst situations this time of year. The rain we had about ten days ago was a perfect slow rainfall that penetrated our landscapes instead of running off into stormwater drains and out into the harbor. Unfortunately, Large Patch loves this moisture too.

 

Rain and nighttime temperatures in the 60’s are perfect weather for Large Patch (Brown Patch) disease in turf. Unless you cover your grass with a tarp, like a baseball diamond, it is hard to turn off the rain. Hopefully, you are managing your irrigation system. It seems like when the skeletons and other Halloween decorations appear in the lawn, so does the Large Patch. With a disease, you want to treat when the conditions are favorable, before you see the damage.

 

All fungus diseases must have three factors line up for there to be an active problem. This is referred to as the disease triangle. There must be a susceptible host (your grass), a favorable environment (in this case cool nights, water, grass is going into dormancy….), and the disease must be present (in the soil in this case). When all these conditions are met, the disease strikes your grass.

 

The quick fix would be to apply Strobe G or T-Methyl throughout the yard. Strobe G and T-Methyl are systemic fungicides that get into the plant (grass) and protect the grass plant from the disease. Getting a flu shot would be a human equivalent. Depending on the weather, rotating chemistries is always a good idea to prevent resistance to the disease. Applying the product before you get the disease when you notice conditions are right, will save you money and time applying the product. You wouldn’t get a flu shot after you had the flu. Unlike the flu shot, Strobe G and T-Methyl do have curative rates.

 

Rats, mice and roaches like to move inside for the winter and the rain just seems to accelerate that migration. The Lowcountry is such a hospitable place, I guess we welcome rats, mice and roaches too! I was looking over some figures the other day preparing for our 2026 season at Possum’s and I was amazed at the amount of products we sell to control these pest. Granted, many of them are sold to professionals; however, they are still used in this area.

 

Do irrigate your yard in the winter because the dry, cold low humidity air can desiccate your lawn, trees and shrubs, similar to the way your lips get chapped. The grass loses water through the runners even though it is dormant and the trees and shrubs lose water through the bark and leaves (if it is an evergreen).

 

Mole crickets and fire ants have been particularly active. With Halloween just around the corner, be sure to manage your fire ants. You would not want that little Princess or Vampire to get bit!

 

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