The first rule of garden pests is not to spray until you know what’s causing the damage. Here are some tips to follow to identify damage and determine what types of insect pests are responsible.
If a plant seems to be struggling, consider non-insect causes first. When a plant is wilted, lack of water or a disease could be to blame. It’s easy to mistake nutrient deficiency symptoms with symptoms of pest damage. If you see yellowing leaves, stunted or weak growth or poor production, test your soil nutrients and pH levels before breaking out the pesticides. (Read about more Gardening Mistakes>>>)
Entomologists (insect specialists) often categorize insects by the way they feed.
Chewing insects eat leaves. Symptoms include holes, jagged edges exposed leaf veins. The culprits include grasshoppers, weevils, caterpillars, flea beetles, and Japanese beetles. Look for the telltale frass (excrement) of the larger of these pests.
Sucking insects pierce holes in plant tissue and suck out fluids. Signs include a sticky substance left behind from their feeding, and a magnifying glass may let you see the tiny insects on stems and undersides of leaves. Culprits include spider mites, aphids and thrips.
Once you know which type of insect is responsible for the damage, take an appropriate course of action to target them. Always keep in mind the extent of damage before resorting to drastic pest control measures.