Over 400 species of aphids feed on numerous hosts.

Aphids are one of the most common insects found on trees and shrubs. There are over 400 species of that feed on numerous hosts. Aphids use their piercing sucking mouthparts to extract sap from the tender, new growth of plants. While aphid feeding does not look good, it usually doesn’t cause serious damage to established plants. The exception is on conifers such as spruce or pines, where they can kill large numbers of needles. Aphids excrete a sticky substance called honeydew (a nice name for aphid poo) that can be a nuisance; it gets all over sidewalks, vehicles, and other structures.

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Treatment Strategy

Soil applied systemic insecticides such as Optrol™ are very effective and work from the inside of the plant.

Optrol are applied to the soil at the base of the tree where it is taken up by the root system. A contact insecticide such as Tengard® can be sprayed and is very effective as long as even coverage of the foliage is achieved.

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Aphids Treatment Option 1

Optrol™ is applied to the soil for controlling aphids and has a long residual (1 year), however it usually will take 30 – 60 days for the product to reach the leaves. Professional arborists often apply Optrol in the fall of the year for control the next season. Early spring application is also very effective.

Application Type Soil drench

DIY Product/Equipment Needed:

• Optrol

• Measuring or diameter tape

For soil drench: bucket, watering can, or soil drench kit

Aphids Treatment Option 2

Spray products such as Tengard®  are not used very often anymore for larger trees as there are issues with drift and contact with beneficial insects. They are, however, still used for controlling aphids  on smaller plants that can be easily treated with a hand sprayer. These products typically have a residual of 10 – 14 days, so begin treatment when insects are present.

Application Type Foliar spray

DIY Product/Equipment Needed:

• Tengard®

• Hand pump sprayer with wand

• Gloves

• Safety glasses

Aphids DIY Kit

For Aphids Treatment Option 1

Application Type – Soil drench

DIY Product/Equipment Needed:


• Measuring or diameter tape

For soil drench: bucket, watering can, or soil drench kit

For Aphids Treatment Option 2

Application Type – Foliar spray

DIY Product/Equipment Needed:

• Tengard®

• Hand pump sprayer with wand

• Gloves

• Safety glasses

How Is It Spread?

• Aphids overwinter as eggs on hosts bark or needles.

• In spring the eggs hatch and aphids migrate into summer hosts.

• Aphids reproduce quickly and can have many generations per year.

• In late summer eggs are laid again.

Susceptible Trees

All tree species can become infested with aphids.


• Curled discolored leaves.

• Plant sap excreted as honeydew making the plant sticky.

• A black fungus called sooty mold may be growing on the honeydew.

• Spots of sap on cars, sidewalks, houses, etc.



Related/Similar Problems

Ants and bees are often found around trees infested with aphids. They are attracted to the sticky sweet honeydew that aphids excrete.


Spring or Fall



Risk of Spreading


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