A variety of factors can influence how a plant performs – especially insects. Plants show different and sometimes similar biotic (biological) or abiotic signs and symptoms, but the biotic are usually easier to determine. Common insects that I frequently see customers having problems with are aphids, mealybugs and scale.
Aphids occur on houseplants and outdoor plants. They can be hard to identify as they vary in color depending on their food source, but they don’t move when they are disturbed. They feed through a proboscis (piercing sucking mouthpart) that pierces the food-conducting tissues and starves the plant. They attack in colonies, focusing on the concentrated areas of sugars such as the terminal buds on the undersides of leaves or stem. When attacked, the plant will begin symptoms of yellowing, new growth will become distorted such as leaf curl, and growth will be stunted.
Common mealybug species are distinct in appearance due to their looking more like a microscopic fungus than an insect. Mealybugs are a small, round to oval shape with a white, waxy covering that acts as a protective layer, looking somewhat like bird droppings. Plants will show symptoms of leaf yellowing, stunted growth, and sometimes small brown dots sprayed throughout infected leaves. Mealybugs hide in protective areas and can be very unnoticeable until symptoms finally show, or upon regular examination of the plant.
Scale is the next culprit. It doesn’t appear to look like an insect because of its hard exterior and barnacle-like appearance. Once the insect has started siphoning the sap from the plant, it remains anchored there. There are two types: the soft and the armored. The soft type produces a waxy or cottony exterior, similar to the mealybug, but remains smooth and tough. The armored type creates a hard exterior. Scale can be found throughout the…