Sap-Sucking Insectst that are Difficult to Control

Scale insects are some of the hardest to control. These pesky little critters appear on many plants as somewhat flattened bumps. They are usually on leaves, stems, twigs, and bark. Underneath the shells are small, immobile, soft-bodied insects (the shells are made of wax and cast skins). The shells are not attached to the insects, if you remove them the insects will remain attached to the plant.

Females lay their eggs underneath the shells and young scales, called crawlers, are active and mobile—usually moving from their mother’s shells to find suitable feeding sites. The crawlers will usually settle down in one spot where they will construct their own shells and remain for the rest of their lives—feeding on plant sap.

Sometimes you can tell if you have an infected plant because it will feel sticky. The sticky substance is called honeydew, which consists of the sugary waste of scale digestion. Some species have both male and female, the male being more mobile, but other species are only females—capable of reproducing without fertilization. There can be multiple generations each growing season.

The shell makes control difficult. If there aren’t too many, you may want to physically remove the shell and apply rubbing alcohol to the exposed insects. Try to control the immature crawlers with insecticidal soap (Natural Guard). Master Nursery Pest Fighter Oil is useful for smothering over-wintered scales in the early spring. We also suggest Imidacloprid (Fertilome Systemic Insect Drench). It’s best to apply in the spring. It creates poisonous sap on non-edible plants for up to 12 months.

Don’t forget to follow the label directions, as they are always the most up to date. If you have a scale infestation and would like to speak with one of our expert gardeners, feel free to stop by any Western Garden Center—we’re happy to help.

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Becky

Becky is a wife, mother, avid cook and novice gardener. She loves growing organic, wholesome food right in her backyard that she can transform into a delicious creation in her kitchen. When she's not growing or cooking food, she enjoys running half marathons, reading, and watching her children pull weeds in the garden.

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