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Massasauga rattlesnake | The wild thing for the week of 8/18/08
The orange aphids on this plant better watch out--a pair of black-and-orange-striped ladybug larvae are on the hunt.
Aphids are common pests that feed on the juices of a variety of plants. The sap-sucking pests typically cluster on succulent young shoots and leaves, although some species occur on flowers, twigs, branches and roots.
Aphids are small, usually 1/8 inch or less, soft-bodied, pear-shaped with long legs and antennae; their color can vary from green, yellow, black, gray or red. They may have a pair of transparent wings held rooflike over the body, but wingless forms are more common. Aphids can be recognized by their cornicles, a pair of tubelike structures projecting from the rear of their bodies.
Aphids have needlelike piercing-sucking mouthparts to puncture plant tissue and remove sap or cell contents. Typical plant damage includes wilted leaves or stems, dying branches and reduced growth.
Beans, cabbage, cucumber, melons, squash and tomato are common aphid targets. Examples of trees and shrubs often infested with aphids are ash, birch, hydrangea, maple, and many others.
Aphids seldom kill a plant, but when abundant they remove large quantities of sap, which reduces plant vigor and can stunt growth. Leaves often become curled, puckered and yellowed. Some species produce galls on stems and roots. Others transmit viruses or inject toxins into the plant.
Many aphid species take in more sap than they can use. The excess is excreted as a clear, sweet, sticky substance known as honeydew. A black, sooty mold (fungi) often grows on honeydew. It disfigures the plant and may also restrict photosynthesis.
The aphid's life cycle can be as short as one to two weeks. Females usually reproduce without mating and give birth to live young - usually more females.
Under many conditions, beneficial predators and parasitic wasps provide effective control of aphids, especially as the season progresses. Before applying insecticide, check plants for natural aphid enemies and see if they are already reducing aphid numbers. If pesticide treatments are warranted, confine the applications to only those plants most seriously infested.
Strong, durable plants can be sprayed with a forceful stream of water to dislodge aphids. Most aphids will not be able to return, and the water will remove recently deposited honeydew. This tactic can be used as often as needed.
Another option is pruning aphid-infested new growth. Some aphid populations grow large in the dense inner canopy of large trees, and thinning out the tree will make the habitat less suitable. Aphids on house and other small plants can be removed by gently rubbing the infested plant part with a damp cloth. In addition, vegetable and weed plants that were badly infested during the season should be destroyed in the fall.