Horticulture Hotline 10/31/22
By Bill Lamson-Scribner
Well, I’m starting to get back soil test that people took after Ian’s rains, and I can tell a big difference! Some tests with high CEC’s (the ability for the soil to hold nutrients) have little to no nutrients. Potassium, a nutrient that leaches and is very important for the winter months, is coming back with very low values (as would be expected). Take a soil test now and be ready for 2023.
My Milkweed, the Monarch butterflies preferred food source, is putting on it’s seeds for next year. If you grow Milkweed, do not use a preemergent product near them or your seeds will not turn into plants. I usually collect mine once you can see the silk coming out of the seed pod and leave them in the garage for the winter. In the spring you can grow the seeds out in pots or just throw them on the ground. If you like, give some seeds to a friend. The Monarch butterflies and your friend will enjoy. The Milkweed’s habitat is getting lost to construction, and the Monarch butterfly’s numbers are suffering too.
While walking and driving around, it seems that brown patch/ large patch/ Zoysia patch (I will use these names interchangeable) has invaded the Lowcountry in a big way. As the cooler weather comes and the grass growth rate slows down, large patch / brown patch / zoysia patch fungus began to show up in our lawns. Does it seem to you that right when we got the army worms and sod web worms under control, here comes the large patch? Proving once again, the Lowcountry is the hardest place in the world to grow grass and why it is so important to have a program for your lawn. Do you see areas of your grass that are brown when other parts are green?
Large patch disease is always present in the lawn, it just manifests itself when the environmental conditions are right and your grass cannot outgrow the damage. Without any sustained cold temperatures, this disease is slowly spreading across lawns as the temperatures that favor its growth keep coming into play. This prolonged fall is great for outdoor activities like visiting local plantations, fishing, boating, golfing, shopping and working in the yard; however, the temperatures are also perfect for these diseases to develop. The grass is not fully actively growing (not mowing as much) and it is not fully dormant (brown), so these are perfect conditions for the disease to attack.
As your grass is going into dormancy and the temperatures begin to cool at night, large patch is ready to attack your grass. Large patch will go inactive when the temperatures get very cold; however, it will become active again when the temperatures favor the disease. If you have discolored areas in your yard that appear to be a disease, check with someone that knows. Even if it is during a cold phase and the disease does not appear to be active, you can still put out a systemic fungicide for protection. Our soils do not get so cold that the plant will not absorb the fungicide with its roots. Remember treating a fungus with a systemic fungicide is like getting a flu shot – you do it preventatively before you have the disease. If it is too late to use it preventively, when you want the disease to stop spreading, you can use the fungicide curatively.
A good granular one-two punch control strategy is T-Methyl and Strobe Pro G (all systemic fungicides that get into the plant). Use these products in areas where you have had Large Patch previously at the preventive rates and intervals recommended on the labels. Be sure to use T-Methyl with Strobe Pro G, so you are switching chemistry classes and modes of action. Good control early on can help avoid flare ups in the spring also.
Large patch usually 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 (at Possum’s we have a great organic granular product for controlling thatch), maintaining proper fertility levels, and aerating to alleviate compaction, will also help control large patch. A healthy turf (following soil test derived feeding schedule) with a soil with a lot of bio-diversity (use of cotton burr compost, SeaHume and other organics) has shown to help manage this disease.
Mosquitoes are still out there and biting me!
Always read, understand and follow product label. The product label is a Federal Law.
