Every time we have an extended 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 extended dry weather. During times of adequate rainfall, rain masks the irrigation system’s imperfections. This is a common problem. There are many imperfect sprinkler systems out there.
The possible imperfections are many. 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, not enough zones, 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, etc.
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 vs. 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 the areas tested.
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. Again, 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