Aphids are very small soft bodied insects found on many trees and shrubs in the Oklahoma landscape which can sometimes cause damage to plants. Some are wingless and others with wings, in colors from green, to red, brown, and black. Damage to plants is caused by their piercing-sucking mouthparts that piece the leaves of plants to suck the sap out of them, causing curling, dis-coloration, and even death. The aphids produce a sticky substance called honeydew, with then coats leaves and stems. This in turn serves as a food source for ants, and can cause black sooty mold to form on leaves and stems. So plants can basically become a sticky, moldy mess sometimes form aphid infestations, which may not kill them, but does stunt them or dis-color them and cause them to look bad. There are several generations of aphids per season, so check every few weeks for high populations. They tend to from dense clumps on susceptible shrubs, such as crape myrtle, rose, fruit trees, hackberry, conifers, and others.
Natural predators such as ladybugs do help keep them in check. Just washing plants with a high pressure stream of water can help somewhat. Application of horticulture oils help smother the eggs during winter, and some can be applied during the season to smother the small adults. Systemic insecticicdes such as imidacloprid do a great job of preventing aphids from feeding during the season. Our T1 Early Spring Tree Shrub Dormant oil treatment in fact is a combination of both dormant oil and a systemic insecticide. And for existing populations, many common insecticides are labelled for control. Since they tend to prefer the underneath side of leaves, spray so that the insecticides are reaching those underneath areas. Always read the label and follow directions when applying insecticides for control.