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Necrotic Ring Spot is getting me down.

Discussion in 'Pesticide & Herbicide Application' started by kevinsky, Oct 2, 2005.

  1. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Posts: 75

    This disease is becoming more and more common each year. The rings seem to start to appear in late August and are pronounce by mid October. I have been treating the lawns that have this disease each year in May. One year with Rubigan and the next with Heritage. On some lawn I am getting fairly good control. On others, very poor control. Some lawns I treated twice (again in July) and still poor control. My plan now is to try treating in late July rather than May and perhaps inter-seed this fall with a resistant grass species. All my lawns with this problem are predominantly Bluegrass lawns. Any help ?
  2. lawn king

    lawn king LawnSite Silver Member
    Posts: 2,279

    How much N do you apply ?
  3. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Posts: 75

    About 6 lbs per thousand square feet per year. Keep in mind we bag all our clippings.
  4. cenlo

    cenlo LawnSite Senior Member
    from Ontario
    Posts: 322

    We have the same problem! I guess about 50-75% of all our properties have the fungi. Last year maybe 20%.............................. :dizzy:
  5. Pilgrims' Pride

    Pilgrims' Pride LawnSite Senior Member
    from MA.
    Posts: 481

    As well as a fungicide program you can try organic fertilizers, aeration, changing watering habits.
    The organics will improve microbial activity.
    Aeration (as often as your customer will allow) has obvious benefits and water more frequently but for shorter periods.

    Good luck
  6. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Posts: 75

    What time of the year do your lawns exhibit symptoms? I'm going to try my applications closer to that time next year. We also de-thatch and aerate every fall along with an organic fert app at the same time.
  7. GreenUtah

    GreenUtah LawnSite Senior Member
    from SLC, UT
    Posts: 866

    Nevada, along with Utah, has one very distinct advantage wehn it comes to turf diseases, our low humidity. What that means for you is that you should take a long, hard look at the watering schedules you are using or recommending to your clients. In any turf at any given time, there are likely to be millions of spores of all sorts, everywhere. The key is to not create the conditions that favor "bloom". In other areas, nature leaves no choice, but in arid and semi arid areas, these conditions are usually of our own making. Aeration should help, resistant varieties will also help, but a couple of minor changes to watering may yeild the largest results of all. BTW, the N needs of most varieties of KB fall in the 2.5-3.25 lbs of actual N per season, depending on soil type, leaching, etc. I wouldn't want to mow lawns running at 6 lbs in a 28 week growing season! lol
  8. kcchiefs58

    kcchiefs58 LawnSite Member
    Posts: 54

    In my area we are seeing nrs but it mostly is up on the higher elevations which happen to be newer lawns(5 to 13 years old), we very rarley see it in the valleys. We were doing two apps of rubigan may and june and was controlling the spreading of the disease but rings with the sunken center were still there. We found aeration did really nothing. We have even seen a client rip up the grass, remove six inches of soil, bring new soil in and guess what nrs two years later. This year we are trying two apps but one in may and one in sept, a chemical rep told us that this should give better control. It doesn't look any different than two apps in may and june right now. Good Cultural practices is a must also just like what has been said, We also found that if you seed the areas that are inffected with a resistant variety that really helps.
  9. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Posts: 75

    I'm wondering now if what we're dealing with is Summer Patch as Necrotic Ring Spot should show up closer to Spring rather than Fall. If so, later applications should work better. Is there a Bluegrass that is resistant to this fungus?
  10. GreenUtah

    GreenUtah LawnSite Senior Member
    from SLC, UT
    Posts: 866

    here's some more info, including resistant varieties Kev. KC, we've done tens of thousands of apps all over the Front and in summit and wasatch. Anytime we've encountered disease of any sort, it's been cultural related and once those adjustments were made, problem went away permanently. One site is all that we've treated with a fungicide in the past decade and ironically enough, there was no fungus present, they were just insistant on having it done as a preventative( a PM group manager).

    (I'd say Oregon and Washington would be pretty good bets on disease info)
    (and one from the neighborhood)

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