Aphid infestations and aphid control
Aphids are tiny soft-bodied insects that suck the juices from plant leaves.
They rarely threaten tree health, but can become a nuisance due to the sticky honeydew which drips from infested leaves.
You may also notice ants on aphid-infested trees. Ants feed on the sugary honeydew and do not cause any damage to the tree.
Most aphids can only feed on one species of plant or shrub. Because of this, aphids infesting trees on City boulevards and streets will not infest other types of plants on your property.
The City is concerned about aphid problems and is implementing the use of biological controls to reduce aphid infestations.
The biological controles include using predatory insects, such as ladybeetles, to control aphids.
Many predators already do a very good job of controlling aphids on street trees.
There is usually a time lag of between 1 and 3 weeks before predator populations catch up with aphid populations. Predators can then become so numerous on leaves that many people mistake them for pests themselves.
What you can do about aphids infesting your trees
For small trees, it may be helpful to blast badly affected leaves and branches with a jet of water in the evening.
This physically dislodges and kills the delicate aphids but should not harm predators.