Pest Identification: Aphids
Most Common Types
There are around 4,400 species of aphids, of which 250 are considered serious pests for agriculture and forestry. Aphids are also known as plant lice, greenflies, blackflies, or whiteflies.
What They Look Like
Aphids are green, red, yellow, black, or grey and nearly invisible to the naked eye. They have soft, pear-shaped bodies and are very tiny, from 1/32 to 1/8 inch long. Aphids have long antennae and two short tubes (called cornicles) which project from the abdomen. Adults are usually wingless but some grow transparent wings, longer than the body, which they use to travel when populations grow too large in one place.
Where They Live
Aphids are found in gardens and farm fields the world over but tend to thrive in temperate climates. They can migrate long distances by riding the winds and are also transported in infested plant material.
Where They Nest
Aphids are sap suckers—they feed on plant juices and attack leaves, stems, buds, flowers, fruits, and roots. The insects are extremely prolific and females can reproduce without mating, giving birth constantly to live nymphs. Nymphs mature in a week or two when they too begin producing offspring.
Steps to Prevent
Aphids move slow and are relatively easy to control by drenching plants with strong sprays of water, the bugs will drown easily. Aphids can be controlled with insecticidal soap, which can be purchased from a hardware store. According to Oregon State University, a recommended home remedy can be made from 1 gallon water mixed with 3 teaspoons of mild dishwashing liquid. Isopropyl alcohol will also kill aphids while leaving plants intact. Ladybugs love to eat aphids and can be purchased at garden stores or online.
Are They Harmful?
Aphids are not harmful to humans but they are hated by gardeners and farmers. The insects cause distorted leaves, buds, branches, and flowers. When they feed, aphids secrete a sticky substance called honeydew which allows sooty mold to grow, blocking light from leaves and killing plants. Some aphids also spread plant viruses as they feed. Aphid-transmitted viruses are harmful to squash, cucumber, pumpkin, melon, bean, potato, lettuce, beet, and chard crops.