With fall rapidly approaching and the sunlight hours getting
less, the grass will begin to transition into a dormant state. As the cooler
weather comes and the grass growth rate slows down, large patch / brown patch
fungus will begin to show up in our lawns. This disease is always present in
the lawn, it just manifests itself when the environmental conditions are right
and your grass cannot out- grow the damage.
Since this disease is a big problem in the Lowcountry,
knowing that it is a soil borne disease can help you with control
strategies. Being a soil borne disease,
you know that it will reoccur in the same areas year after year. If a leaf blade with large patch is moved
from one part of the yard to another (lawn mower), this can begin a new
infection area (although not very common); 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 have to treat the entire yard because air
borne fungus spreads a lot quicker than soil borne fungus.
As your grass is going into dormancy and the temperatures begin
to cool at night, large patch will be ready to attack your grass. A good granular one-two punch control
strategy is Disarm or Dual Action Disease Killer and Cleary’s 3336 (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
Cleary’s with one of the other two so you are switching chemistry classes and
mode 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 (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.
Does the West Nile Virus out-break in Dallas scare you? Kill
mosquitoes now with Cyonara. Also look around your yard for any areas that
collect water that mosquitoes could breed in. Usually I recommend organic
repellents that do not kill mosquitoes just keep them away from you; however,
with 10 dead in Dallas it is time to say, “Cyonara!”
