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How to get rid of aphids on plants and trees

Aphids on a leaf

If there’s a sticky substance on your sidewalk, car or patio and you see little green bugs on your plants, you probably have an aphid infestation. What are aphids? Aphids are small, sap-sucking insects and one of the most common pests in gardens and yards in Western Canada. They have a voracious appetite, reproduce quickly and can rapidly overtake your garden. Here’s how to identify aphids on trees and plants, plus some tips for treatment.

What do aphids look like?

You can find aphids on a plant, usually on the undersides of leaves. These tiny, pear-shaped insects can be green, yellow, black, brown, pink or almost colourless. They have soft bodies and, usually, no wings. However, during an infestation, some insects grow wings to fly to another plant for food. They have two antennae at the head and two tubes called cornicles that extend from their hind end.

Why are aphids harmful?

Aphids suck sap from the soft tissue of leaves, stems, buds, flowers or fruit. They can be found on trees, roses or even houseplants. They severely weaken the plant they are eating, leaving them vulnerable to disease. After gaining nutrients from the plant, they ejecta substance called honeydew. This thick, sugary liquid coats the leaves and drips on anything underneath the plant. Homeowners find the substance difficult to clean from vehicles, patio furniture and decks.

What does aphid damage look like?

Plants weakened due to an infestation will have curled, stunted or yellowing leaves. The honeydew makes leaves look shiny and can attract sooty mould, a fungal growth that turns leaves and stems black. Aphids can also cause deformed fruit.

How do you treat and prevent aphids?

Female aphids don’t need males to reproduce. Moreover, they give birth to live nymphs that are often pregnant themselves. It means aphid populations can get out of control quickly, making them challenging to control.

To try to remove your infestation, spray the tree with a strong stream of water. The aphids that get washed away will have difficulty making it back up the tree. Water mixed with dish soap or cayenne pepper is even better.

Insecticidal soaps and horticultural oils are also effective, but they need to touch the aphids to work, so they’ll rarely eradicate the problem with one application. The best method is to apply these products several times throughout the year to keep colonies under control.

Aphids treatment in Calgary and Edmonton

A healthy tree is your best defence against pests like aphids. At ArborCare®, our plant management program will keep your trees healthy with regular fertilizing, pruning and treatment with environmentally friendly insecticides. Contact us today to schedule an appointment or learn more about our services.

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