Aphids are small, soft-bodied, pear-shaped insects that have long antennae and a characteristic pair of cornicles (short tubes extending on either side of abdomen). Their translucent bodies are most commonly green, brown, yellow or white.
Over-wintered eggs hatch into females during the spring that give birth to live young, again all female (up to 10 or more per day). In the fall, males are produced and the fertilized females produce eggs for over-wintering outdoors. Shiny black eggs are tucked into the crevices of bud scales and bark. Winged adults are produced only when it is necessary for the colony to migrate.
- Repair screens and weather-stripping around doors and windows to keep out winged adults.
- Inspect new houseplants before bringing them into your home. If necessary, isolate and treat them.
- Nourish houseplants with slow-release fertilizers containing moderate amounts of nitrogen to prevent aphids from thriving.
- Monitor house and garden plants frequently during the growing season.
- Prune and destroy infested leaves or plant sections. This will help prevent the spread of plant disease and the development of new colonies.
- Spray dormant oil on fruit trees in the spring (while trees are still dormant) to kill overwintering aphid eggs.
- Spray the underside of plants with strong jets of water to reduce aphid populations; repeat weekly. This may be enough to control infestations in the home garden.
- Soap sprays may also be effective. Use commercial insecticidal soaps or make your own by mixing 10-25 ml on non-detergent soap in 4 litres of water. (Soaps may burn foliage so try a small area and wait two days to see how well the plant tolerates the soap. Do not use more than three times in a row.
- Infestations may be treated with insecticide products with active ingredients such as allethrin, pyrethrin, malathion, dimethoate and many others.