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david52_gw

Intermountain west lawn issues

david52 Zone 6
15 years ago

Hi, I'm in a similar climate to the Wasatch front, Colorado Front Range, with minimal rainfall, low humidity, cool nights, and warm days, where we water lawns - in fact, with a ridiculous amount of irrigation water, I have 2 acres. This is planted with a blend of grasses, largely KBG cultivators, from the seed company up the road and targeted to the climate. In an area that specializes in growing hay, we grow some nice lawns.

Anywho, for years this worked fine, but beginning last summer, I began to see base-ball sized dead spots in certain areas. I tried to find the cause - dug up around the clumps, magnifying glass, couldn't find anything. I called out the county extension agent, he finds spider mites, tells me to water more. Since I keep the place about as wet as a Mekong Delta rice paddy, that seemed odd, although the problems occurred where the slope, exposure, and poor soil underneath the lawn meant it dried out pretty quickly. Not dry out to brown, but not soppy.

This year, its far worse, and the problem has spread all over the 2 acres. The only areas it doesn't affect are those where I have clover growing, and so I over-seeded with 20 lbs of Dutch White clover seed, which is sprouting pretty well in the empty, dead spots.

Now, when I mow, I see at any given moment a dozen or so very light colored, 3/4 inch long moths that seem to be living in the grass.

Also, as I was trying to germinate the clover seed, I was keeping the lawn extra soggy, and it does seem to stop it. But if it dries out even a few days, back it comes again.

So, I'm kinda stuck. Any ideas?

Comments (9)

  • bpgreen
    15 years ago

    Do the moths look like

    ?

    If so, they're sod webworms. I don't know how to treat them, although insecticidal soap may work. Actually, you could probably use just about any soap (but you probably don't want anti bacterial soap).

    I think if I were you, I'd continue with the clover and consider transitioning to wheatgrass from the KBG. Don't you have some of that growing on part of your land already?

  • david52 Zone 6
    Original Author
    15 years ago

    If those things are 3/4 " long, then them's the critters. I've got some of the wheat grass growing, but thats mostly around the pond and away from where all this is happening. They do leave that alone. Actually, I got some wheat grass popping up in the driest places where this activity is going on.

    I'll go look into getting them with soap. That I can do.

  • bpgreen
    15 years ago

    Keep us posted.

  • david52 Zone 6
    Original Author
    15 years ago

    Well, now that I know what to look for, I can assure you that there is many an internet source on the control of the sod web worm. It looks like a multi-pronged approach here is the ticket, some species of grass have some species of fungus that web worms don't like, (found that here) and pretty obviously, here at ground zero, that includes western wheat grass, and that they're susceptible to Bt - mow short, spray, and leave as long as possible before mowing again.

    There are contradictory management ideas on dryness / moisture.

    Re the soap thing, there is a way, they say, to use some diluted stuff to make the little guys come out of their silken tunnels as a verification tool, but if it's too strong, then it kills them. I think my first trial with this was too strong.
    I now have some very clean thatch, though.

  • bpgreen
    15 years ago

    "I now have some very clean thatch, though. "

    And at least temporarily, when you water it should penetrate a little better since soap is a surfactant.

  • david52 Zone 6
    Original Author
    15 years ago

    Ok, a little help here. I'm familiar with surfactants, and use them in some sprays where certain herbicides (in the fight against common, lethal, over-powering invasive species on millions of acres, mine but an infinitesimal amount in the overall scheme of things) so I use automatic dishwasher rinse stuff.

    But, that might whack the Bt, of which I ordered a gallon of the stuff.

    So, I would surely appreciate some suggestions on organic-style surfactants that will help Bt scoot down the top of the lawn towards where sod web worms dwell, w/o killing Bt. Note serious, thick-remaining-turf issues.

  • bpgreen
    15 years ago

    If you're worried about the anti bacterial actions of some soaps, you can use a baby shampoo.

  • david52 Zone 6
    Original Author
    15 years ago

    I got the stuff yesterday. Fooled around a bit with the nozzle settings on the sprayer, and *thinking profoundly* as I wandered around the 2 acres in the 94ºF heat, that what needed to be done was to twist the nozzle into a strong jet, and walk slowly along the uphill parts, shooting a concentrated stream down into the roots and soil, where the irrigation water will spread it out.

    We'll see how it works. Clouds and clouds of the moths.

  • david52 Zone 6
    Original Author
    15 years ago

    It didn't work. Positively cumulonimbus clouds of moths yesterday.

    OTOH, more and more of the over-seeded clover has germinated and grown, and where thats established, the grub holes have rapidly disappeared.

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