Pearl Scale

Some Bermuda grass roots offer shelter and food for an insidious little critter whose existence challenges our efforts of control. Pearl Scale is the insect and its biology make it dificult to combat it.

This scale insect attaches to roots and extracts energy from the plant. When thier numbers get large the damage gets more noticeable. As they multiply the damaged spot begins to enlarge outwardly over the years.

Waiting until the area is large makes the fight against them tougher. By then they have been active for years and their numbers huge.

The insect is sedintary for all but a few weeks of the year. They spend most of the time on the roots sucking out energy and protecting themselves from the elements with a hard waxy shell. This shell is a wonderful protection device and is seemingly impervious to most insecticides; at least the ones that are available.

For only about a month each year they are vulnerable. During this period the mature scales produce youngt immatures called crawlers. These tiny ones crawl from under the mother's shell and find sites to stop and begin to feed. This month or so is the time when the use of controls is somewhat effective.

Controls are not 100% under any settings so multiple years are needed to reduce the total numbers to a manageable level.

How to control: 1. Make sure you have the scales. Inspect roots found near the edge of the sopt for small (1/8th inch) cream colored 'pearls' attached to the roots.

2. During a period from mid-May to July treatments are most effective.

3. Sulfur or a sulfur bearing product gives some control by itself. Couple it with an insecticide designed for soil applications on lawns and the control may go up to 60 to 70%. Not that great but as good as can be expected.

4. Applications must be made and watered in throroughly.

5. If the spots are small try digging out the grass down a foot and out from the spot 8 inches. Pile it all on a tarp and remove all the soil and roots. Replace with clean soil and either buy some more turf or cut plugs from the remaining lawn to replant.

Pearl Scale is tough to control. Make sure its in the lawn and if it is get on it now and mark calendars for repeated treatments for the next few years..

Don't forget the Sweet Onion Festival this weekend at Rock Springs Cafe on the rad to Flagstaff. I will be there at a booth answering questions and look forward to meeting any one show stops by.

Written by Terry Mikel, College of Agriculture and Life Sciences, the University of Arizona, 602-470-8086.
Material originally appeared in Arizona Republic
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