Aphids are an extremely successful group of insects, attacking nearly every species of green plant. In this article, aspects of aphid identification, types of damage, life histories and control will be reviewed. Aphids are small (generally less than 1/8 inch long), soft-bodied, pear-shaped insects that are usually found in large colonies on new growth, on the under surface of leaves, and/or on buds. Aphids come in many colors, and may be winged or wingless as adults. Winged aphids at rest generally hold their wings vertically over their body (Figure 1). True aphids may be easily recognized by the presence of a pair of "exhaust-pipe"-like structures known as cornicles on the posterior end of their body.
Source: • Connecticut Greenhouse Newsletter #92