When we go through a dry
period in spring or summer, I get those predictable calls about some mysterious
pest that’s playing havoc in lawns.
Without realizing it, the
caller describes dry spots thinking he/she is describing a lawn pest.
These dry spots are the
result of imperfections in an irrigation system. They’re revealed during times
of inadequate rain. During times of sufficient rainfall, rain masks the
irrigation system’s imperfections. There are many imperfect sprinkler systems.
Possible imperfections are
numerous. The homeowner may easily fix some irrigation system problems while
others may require the expertise of a licensed irrigation contractor. There may
be too few sprinkler heads for adequate coverage, insufficient pressure to
operate each zone, incorrect choice of nozzles or wrongly mixing rotors with
spray heads on the same zone. The cause for dry spots may be as simple as a
maladjusted spray head, a broken spray head, a plugged nozzle, a tree trunk or
tall shrub blocking the water, grass that has grown over a pop-up spray head,
Regardless of the cause,
there are a couple of simple tests that can help confirm if the problem areas
are to be blamed on lack of water versus some mysterious pest.
First, check affected areas
by taking a soil sample in the root zone. Take out a slice of soil to a depth
of six to eight inches with a shovel. Visually inspect and feel the soil sample
for moisture. Then do the same in an adjacent area of the lawn that looks
normal and compare the difference. It should be obvious if there’s a difference
in moisture between tested areas.
The second test involves
placing several empty straight-sided cans (such as tuna cans) in the affected
area and several in a normal area of the lawn. Then turn on the irrigation
system and let it run long enough to collect some water in the cans. Compare
amount of water collected in the two areas. It should be obvious if there’s a
difference in the amount of water applied in the areas tested.
These two tests are
cheaper, less trouble and more environmentally friendly as compared to
purchasing and applying pesticides for nonexistent pests.
Occasionally inspect your
irrigation system while it’s running for any obvious maladjusted or broken
spray heads. If these tests do not identify the problem as lack of water, you
may have a lawn pest. But don’t guess.
If you’re not sure about
your diagnosis, contact a reputable lawn care or pest control business or your
local UF/IFAS Extension Office.
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