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Michael Wheeler: Scale insects attack plants early in the season
Tea scales attach to the underside of plant leaves.

This year has been a year for scales.

No, not the scales that some of you are thinking about. I am talking about scale insects that suck the life out of landscape plants. These tiny insects attach themselves on the underside of the leaf or side of a branch to finish its life cycle.

Some types of scales, called armored scale, do not produce honeydew on the leaves. These larger turtle-shell-shaped scales will attach to leaves and twigs.

But soft scales attach themselves to plants producing honeydew, which can be advantageous when looking for an infestation on plants. Honeydew makes the surface of the leaf black and is easily scraped off with a fingernail.

The prime reason a plant becomes infested with scales is poor health. This can be because of a number of things, including a lack of light or low soil fertility.

Gardeners can do a handful things to combat an infestation. Keeping plants as healthy and thriving as possible is the first real step in fighting off scale insects.

Consider testing your soil and do it now. Matching the soil fertility needs of your plants is critical for basic plant health.

Water is another nutrient that needs to be satisfied to keep plants happy and healthy.

During the summer, if it doesn’t rain in a couple of weeks, water the top 8-10 inches of soil thoroughly once a week. Many plants don’t like wet feet. So water only once, but do it well. Lots of small applications of water will do more harm than good.

Know about insects and animals that prey on scales. You can use this information to help fight off scales. However, many times scales outnumber the predators and they cannot keep up with the population.

Insecticides are not very effective in fighting scales. The hard or waxy covering protects the insects.

However, you can kill a few scales in the crawler stage. This usually is timed in the spring with new growth.

Use a horticultural oil to kill all stages of scale. It’s safer on the environment and beneficial to insects.

During the growing season, use a 1 percent to 2 percent concentration (2.5 to 5 tablespoons per gallon of water). Keep in mind you might have to do this treatment a couple of times to get the scale population down to acceptable levels. And remember during periods of heat and humidity, some new foliage maybe sensitive and become damaged by the application.

If you have any questions, call the Extension office. I will be glad to help.

Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, His column appears weekly and on