Aphids

Description:
There are many types of aphids and they come in many different colors. Aphids may be green, yellow, brown, red, or black depending on the species and the plants they feed on. All of them are small, pear-shaped insects with long legs and antennae. Most species have a pair of tube-like structures called cornicles projecting out of the hind end of their bodies. These cornicles distinguish aphids from all other insects. Adults of some species are winged, especially when populations are high or during spring and fall. Winged adults are produced to provide the pest with a way to disperse to other plants. Aphids usually feed in groups on the new growth of leaves, stems, or buds. Unlike other insects similar in appearance, most aphids do not move rapidly when disturbed.

Damage:
Aphids pierce and suck sap from leaves, stems, and flowers; especially on fleshy new growth. This can cause the growth to be stunted, discolored, and contorted. It can also reduce blooming and prevent buds from opening.
Side Effects:
Aphids cannot digest all the sugars from the sap they ingest. The excess sugars are excreted in the form of a stick honeydew. Sooty mold will usually form on the honeydew and ants absolutely love honeydew. In fact, ants will farm aphids, protecting them from would be predators, in order to harvest the honeydew! So, if you notice ants traveling up and down your plants, you most-likely have an aphid infestation. When aphids are high up in a tree tale tale signs will be ants climbing the tree, and the honeydew will drip down soiling anything in its path, from cars to other plants.

Prevention:
First of all, if you have them, get rid of those ants! Without the ants to protect the aphids, aphid predators (such as ladybugs, lacewings, parasitoid wasps, and syrphid flies) will usually bring the population back under control. Check for these natural enemies before treating with insecticides. During the growing season, spray aphids off plants with a forceful stream of water. This prevents populations from establishing. Also, rose aphids seem to be deterred by pungent underplantings of marigolds and/or garlic.

Management:
Mild Infestations: Lightly sprinkle diatomaceous earth or spray insecticidal soap on the foliage of edible plants. For other plants, use an insecticide containing azadirachtin (Neem). Always follow label directions.

Severe Infestations: When populations are high aphids will hide in flower buds and the tight crevices of new growth making them difficult to control with contact insecticides. Acephate (Orthene) is an effective systemic, but it is toxic to bees and fish.