Monday, October 21, 2019

Disease and Winter Kill

Horticulture Hotline 10/21/19
By Bill Lamson-Scribner

Preparing your lawn to avoid winter kill will also help with large patch / brown patch disease. Many of the cultural practices are the same. The rain, the shorter daylight hours and the cooler temperatures have large patch / brown patch exploding in yards of all types. Winter kill temperatures are not in the forecast; however, it is best to be proactive, so if and when the time comes, you are ready.

Have you ever had winter kill? Now is the time to prepare your grass for the wide variations in temperatures we have. If you had winter kill in the past, you need to be sure to correct low and poorly drained areas, reduce thatch in the yard, increase air movement in low areas, keep your lawn hydrated and feed (with the right food for the winter). These same cultural practices will help with large patch / brown patch disease as well.

Mow your grass lower than normal (centipede 1.0 to 1.5 inches, St. Augustine 2.5 to 3.0 inches). By mowing your grass lower, you will increase the air movement around the crown of the plant, so cold air will not settle at the crown of the plant and damage the grass. In Florida helicopters fly low over citrus groves that are in valleys to get the cold air out. Tall grass or thatch will insulate the crown of the plant like a goose down jacket, keeping the cold air near the crown where it can cause winter kill. Centipede lawns usually get winter kill the worst if temperatures plummet quickly. Tall grass will also stay wet longer. Wet grass favors the development of disease.

Fine blade Zoysia grass can grow very dense and get thatch. De-thatching, verticutting, using Bio Grounds Keeper, and regular topdressing with cotton burr compost should be part of your maintenance schedule.  

With the conditions so favorable for large patch / brown patch disease, an application of a systemic fungicide (Fame, T-Methyl) is a good idea. This application is like us getting a flu shot. You want to get the flu shot or the fungicide out before you or your lawn get the disease.

Moles? Rats? Roaches? Fire ants? Putting in winter annual color? Preemergent herbicides? Transplanting shrubs or trees? A lot goes on this time of year in the landscape.

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