Several scale species are pests of houseplants. There are two types of scale insects: armoured scales and soft scales. A waxy covering is secreted by an armoured scale that is not an integral part of its body. The covering can be scraped away to reveal the insect that lives beneath it. A soft scale's waxy covering, on the other hand, is an integral part of its body.
Insects with scales have an unusual appearance. Adults are small, immobile, and have no visible legs. The appearance of scales varies according to age, gender, and species. Some are flat, resembling fish scales stuck to a plant. Others resemble waxy, coloured masses. They range in diameter from 1/16– to 12–inch. They are most commonly found on stems and the undersides of leaves, but they can also be found on upper surfaces. Scales get their food by sucking plant sap.
Their immature forms, known as crawlers, are mobile and feed by sucking plant sap. Honeydew is excreted by soft scale insects in the same way that mealybugs do (which results in black sooty mould problems on foliage and stems). Honeydew is not excreted by armoured scales.
DEALING WITH SCALE INSETCS.
Scale infestations can be removed early by scraping with a fingernail. The waxy covering of adult scales protects them from insecticides. Sprays containing neem oil extract or canola oil, on the other hand, help control adult scale insects by smothering them on houseplants outside. Many insecticides are effective against their crawlers, including insecticidal soap, neem oil extract, canola oil, pyrethrins, acetamiprid, imidacloprid, cyfluthrin, deltamethrin, and lambda cyhalothrin. To ensure safe use, follow the directions on the label.