Horticulture Hotline 08/07/23
Bill Lamson-Scribner
A scientist working for Syngenta noticed that certain weeds did not grow near his bottlebrush. He isolated a chemical (Mesotrione) in the soil that was released from the bottlebrush plant that prevents and kills weeds. Syngenta has developed this into a new product, which originally only had EPA registrations for sod farms and golf courses. The product now a wide range of use sites. Mesotrione is sold under the name Meso 4 SC and Tenacity.
From the Meso label:
Approved Use Sites Meso 4 SC Select can be applied to commercial and residential turfgrasses. Non-crop area use sites include golf courses, sod farms, athletic fields, parks, residential and commercial properties, cemeteries, airports, and lawns
Interesting enough Meso has been found to be safe under trial conditions for Centipede and St. Augustine grass. Zoysia, Seashore Paspalum, and Bermudagrass all showed damage under trial conditions. Again, from the label: • DO NOT apply this product on Bentgrass, Poa annua, kikuyugrass, zoysiagrass, seashore paspalum, and bermudagrass; if plant injury is unacceptable.
Meso has a unique mode of action that blocks the production of chlorophyll, so the weeds turn white. Also from the label: Post-emergent control is obtained by absorption into the soil and contact with foliage. Growth ceases post-application, weeds turn white from chlorophyll loss, and will die within three weeks. Make a repeat application after 2-3 weeks to improve post-emergence weed control. Add a non-ionic surfactant when making post-emergence applications.
The neatest part about Meso is the weeds it controls. Barnyard grass, creeping bent grass, buckhorn plantain, buttercup, carpet weed, chickweed, clover, large crabgrass, smooth crabgrass, and southern crabgrass, dandelions, Florida Betony, goose grass, lawn Burrweed, yellow nutsedge and oxalis are just a few examples of the weeds Meso controls. As you can see, many of our hard to control broadleaf weeds and grassy weeds on this list. Meso also has some preemergent qualities as well.
As the grass is going into dormancy, watch out for Large Patch (Brown Patch) fungus. If your grass is not greening up uniformly in the spring, this is a good indication that you have this fungus. The disease gets its start in the fall then re-appears in the spring. An application of T-Methyl or Strobe over the entire yard will help prevent this disease. Minimizing wet areas (turn off your irrigation system), managing thatch, correcting drainage problems, and reducing compaction will help lower the disease pressure from Large Patch. We also have people report to us that they get good control by using Neptune Harvest Crab Shell product (increases chitin eating bacteria), Cotton Burr Compost, and SeaHume.
Preemergent time is upon us once again. Ryegrass this year? If you are seeding with any seed, be aware of herbicides you are using and how they might affect the seeds. Always read, understand, and follow product label. Labels have a lot of information that will help you be successful!
