Preventative Methods To Save Your Trees From Over Wintering Insects

By: albertaarb - April 24, 2014

A tree that is about to head into winter will sense the light and temperature changes. It will obey the inactivity controls that are built into the leaves.  Senescence are mechanisms that instruct the trees to close down for the upcoming winter.  

Trees may appear dormant as they head into winter, but they continue regulating their metabolism. Only some physiological activities are slowed down.  The decrease in transpiration and photosynthesis ushers in the dormant phase in the life of a tree.  In this phase, roots continue to grow slowly, respire and absorb nutrients and water. 

Trees have a difficult time during the winter.  Dormant trees still need protection to remain free from diseases and over wintering insects.  Unfortunately, winter encourages the snuggling of pests that await springtime to restart their destructive life cycles.  However, there are protective measures that can safeguard trees against over wintering insects. 

Mulching and Aerating

Fluctuations in moisture and temperature are especially damaging to young trees. They require mulching protection.  Mulch is good for evenly managing both conditions during drought and cold. It is actually good for both full-growing, vegetative trees and the dormant ones.

Use composted organic mulch to form a thin layer, covering the depth of the soil by several inches.   Along with safeguarding feeder roots, mulch directly recycles nutrients to these roots.

Aerating is essential to compacted mulch and soils, if they are poorly drained and become water-logged.  Dense and saturated soil can choke roots. It is vital not to cause damage to tree roots while aerating, so only work on the few inches at the crust of the surface.


Late fall is the ideal time for pruning overlapping and diseased branches. 

Pruning will:

  1. Form and strengthen trees
  2. Safeguard against over wintering insects and diseases
  3. Minimize future storm damage
  4. Encourage new strong growth during the springtime

Additionally, pruning is easier to do during the dormancy of winter than in the springtime. 

Structurally weak limbs and branches should be removed and all visible deadwood should be removed.  Branches that touch the ground when weighed down by snow or rain should also be properly pruned.  Branches and foliage that touch the soil invite other problems like undesirable pests.  Remove declining and damaged bark, branches and twigs or new sprouts at the base of the tree or along the branches and stems.

Dormant Oil

A dormant oil is great for deciduous trees, shrubs, fruit trees and ornamentals.  However, bear in mind that pruning should be done prior to spraying.  Obviously, much expense and effort will be lost if treated limbs are cut off .

Chemical choice is essential.  Dormant sprays typically include sulfur, copper and lime combinations to eliminate overwintering microorganisms.  Both insects and eggs are controlled by dormant oils.  Spraying should not take place in the hot sun since dormant buds could be damaged.

Fertilizing and Watering

If essential elements are lacking in the soil, use fertilizer to top dress over the mulch.  Ensure that nitrogen is lightly used, particularly around newly planted and  large/mature trees.  This will prevent a vegetative growth flush during late fall. 

Hot daytime temperatures or winter dry spells will very quickly dry out a tree. Watering could be required where soils are not frozen but cool and little precipitation has occurred.  Water remedies winter droughts just as it does with summer droughts, except over-watering is much easier during the winter months.

There are several pests that lie in wait to nestle into trees during the winter and them embark on a path of destruction in the springtime.  Thankfully, there are protective methods that can be applied to prevent this.

Hours of Operation 8am - 4:30pm Monday - Friday, After Hours Emergency call (780)448-0584
Website by Aaron Mumby Design & Monolith Digital
Home | Our Company | Services | News | FAQ | Testimonials | Resources | Free Estimate & Contact | Privacy Policy
Follow Alberta Arborists on:
We accept:
Please visit our affiliations:
Click for the BBB Business Review of this Tree Service in Edmonton AB