- Aphids are small sap-sucking insects, about 1/8 inches (3 mm) long.
- They vary in color from green, peach, brown, black, and sometimes colorless.
- These garden pests have a pair of antennae on the tip of the head region and short legs.
- Most species have a pair of tubes emerging from their abdomen.
- Aphids have long slender sap-sucking mouthparts.
- Most of them live on the undersides of the leaves or on the top part of the plant’s stems.
Aphids have incredible reproductive capabilities. In spring, females hatch from overwintering eggs and soon give birth to nymphs. The reason aphids can reproduce so quickly is because female aphids give birth to live young who are already pregnant. In just a couple of weeks, the young reach maturity and gives birth to other pregnant nymphs. Most aphids do not even have to mate to reproduce, and they produce live nymphs rather than eggs. This process is repeated several times. A short cycle of reproduction results in exponential population growth. There are many overlapping generations per year.
These insects are wingless. However, as the population increases, some females develop wings and fly out to colonize other plants. At the end of the summer, males and females develop, mate and lay overwintering eggs. These will be the following years’ generation.
Damage They Cause
Aphids feed in clusters on new plant growth or the undersides of leaves, resulting in the stem’s curling, distorting, or discoloring. Well-established plants can tolerate some damage, but young growth may be stunted. Aphids excrete a sticky, glossy liquid called honeydew that discolors leaves and causes an unsightly black sooty mold to grow.
In small numbers, aphids do minor damage. Still, they can reproduce rapidly and quickly become a more severe problem.
Plants They Attack
As there are a lot of species of aphids, each species can attack different types of plants. However, garden plants most susceptible to their attack are:
Live Biological Control
A lot of predatory insects will feed on aphids. Attract beneficial insects to control them:
- Aphidius Wasp
- Assassin Bugs
- Big-eyed Bugs
- Damsel Bugs
- Hoverfly Larvae
- Minute Pirate Bugs
- Parasitic Wasps
- Praying Mantis.
- Soap and Water
- Neem Oil
- Garlic Extract
- Horticultural Oil
- Insecticidal Soap
- Remove. Keep monitoring your plants regularly and remove infested plant growths.
- Dislodge. Use a fine jet stream of water to blast the aphids off.
- Trap. Plant various plants that will trap aphids, preventing the important crops from being damaged.
- Select plant varieties for your garden that can withstand pest damage.
- Cover susceptible plants with lightweight floating row cover to block the access. Ensure to remove the cover when your plants begin to flower.
More About Aphids
If you see aphid cream in color and motionless, do not remove it. It means that it was infected by an aphidius wasp. The wasp will hatch from this aphid and will further control the aphid population.
Sometimes you will see ants walking among aphids. Aphids secrete a sugar-rich fluid called honeydew which the ants harvest to feed on. Ants also protect aphids from predators by either driving away enemies or killing them.
The relationship between aphids and ants is an example of symbiosis, where two different species live together in a way that benefits both parties. This is called mutualism because the two species depend on each other for survival.
Also, watch this fun video about aphids, presented by TED-Ed.
What to Do Next
Check out our other Garden Pests Guides. Read and learn more about how to identify and control garden pests.
Check out our Beneficial Insects Guides. Read and learn about their benefit and how to attract them.
Also, check out our Gardening Guides to learn easy step-by-step tutorials on how to grow plants.
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