Other Insects
Emerald Ash Borer, dutch elm disease, maple wilt, disease control, tree treatments
This page is dedicated to some of the non-fatal insects that affect trees.  These include but are not limited to aphids, weevils, moths, wood boring insects and many other seconday pests of trees.  Many of the insects that we will outline have many host trees.  The insects themselves tend to be nuisance pests and are controled in some cases.
Box Elder Bug
Trees Affected: Box Elder

Best control method: Spraying

Timing: Spring to Summer

Why are these pests bad?
These pests gather in the house to mostly just be annoying.  They feed on the box elder tree and nest within the tree.  Not harmful to trees but a house nuisance pest.
Trees Affected: Broad range pest

Best control method: Spraying

Timing: Spring to Summer

Why are these pests bad?
Known to be a pest of trees and the home these insects get there name for an obvious reason. 

Brown mamorated stinkbug
Honey Locust Plant Bug
Trees Affected: Honey Locust

Best control method: Spraying or trunk injections

Timing: Summer

Why are these pests bad?
These pests are very similar to aphids except they go for one kind of tree.  This puts very high populations of them on a tree at once.  Can easily defoliate a tree.
Gypsy Moth
Trees Affected: Many varieties of deciduous trees

Best control method: Spraying

Timing: Spring to Summer

Why are these pests bad?
The caterpillars are the issue and they eat in groups.  Known to defoliate trees in a hurry.  This pest is one that Minnesota will have to deal with very shortly.
Leaf Hopper
Trees Affected: Deciduous trees

Best control method: Spraying or injections

Timing: Spring to Summer

Why are these pests bad?
These pests are vector disease carrying insects.  Can easily carry fungi and bacteria from tree to tree.  The pest itself is relatively harmless.
Wholly Aphid
Trees Affected: Ash

Best control method: Spraying or injections

Timing: June-July

Why are these pests bad?
Showing up almost at random these pests feed on trees and create honeydew that makes a mess out of your landscape.  The bug does minor damage when in mass.
Aphids
Trees Affected: Deciduous

Best control method: Spraying

Timing: Spring to Summer

Why are these pests bad?
The ultimate vector pest.  This insect feeds on a variety of trees and easily carries disease from tree to tree.  The bug itself is harmless.
Red Oak Borer
Trees Affected: Northern Red Oak

Best control method:Trunk injection only

Timing: Summer

Why are these pests bad?
This long horned  beetle makes large galleries and can destroy a health red oak in a quick manner.  Very similar to flat headed boring pests with the exception that they are also wood boring pests.
Common Tent Caterpillars
Trees Affected: Crab apple and apple

Best control method: Spraying

Timing: Summer

Why are these pests bad?
Another leaf eater except the nests tend to be disgusting looking.  The damage looks far worse than it really is in most cases.
Cottonwood Borer
Trees Affected: Cottonwood, poplar

Best control method: Injection

Timing: Spring

Why are these pests bad? 
Although the trees are not valuable and cause a mess some are very expensive to remove.  This tree causes major dieback in areas they affect.

Weeping willow borer
Trees Affected: Weeping willow

Best control method: Trunk injection

Timing: Spring

Why are these pests bad? 
The larvae of this insect eat the living layer of the host tree.  This causes eventual death of the tree.

More to come soon!
Trees Affected:

Best control method:

Timing:

Why are these pests bad?

Source for photo:
Robin Rosetta
oregonstate.edu