Joshua Gehman said: During the course of this past July, I lost a lot of grass on my greens for the first time. Nice experience. It seems the culprit was nematodes. Two applications of Avid seemed to do the trick However... The label of
Avid clearly says to tank mix in a fungicide to be watered in with it. The targeted fungus is pythium.
I had two salesmen tell me that, in our area, nematodes are not the primary problem, root pythium is. They stated that when the roots become weakened by the fungus, THEN the nematodes go crazy.
After the first application of Avid we saw a stop in the loss of grass, except on my 8th green. That one looked like I skipped it. So, I put down some left over Nemacure (with out any fungicide) that we had and that green rebounded the nicest of all of them.
From my experience, I believe the nematodes are the primary problem. The pythium then takes advantage of the damaged roots via the feeding holes produced by the nematodes. What do you think?
First question: have you sent off an assay to determine your Nematode counts?
Florida now has the new 24C labeling for Avid requiring the application of Heritage with it. This is based on the findings that Dr. Billy Crow did at the University of Florida. The applications that had the Heritage with it had the best results. Hence the new label. Makes good sense, really.
And I would tend to agree that the pythium entered AFTER the Nematode caused damage. Pythium is always often present in the soil, but needs a susceptible host to become active. The host plant being damaged by Nematode feeding causes the susceptibility. As does the right weather, cultural stresses, mechanical damage, etc...
I have also heard of suggested applications of Interface after a Nortica application. Same theory.
I'd say applying both would cover all bases. Similar to our area with Bermudagrass Decline. Although the Gaeumannomyces graminis var. graminis may be the initial culprit, Pythium spp. is often the major damaging factor after the fact. Applying a fungicide for one without controlling the other does no good.