Insect Pests

In southwestern Ontario, there are 5 main categories of insect pests that affect our trees:

1. Defoliators
   a. Leaf Chewers
   b. Leaf Skeletonizers
   c. Leaf Miners
2. Borers
3. Sucking Insects
4. Gall-makers
5. Root Feeders

 

1. Defoliators

These pests feed on tree foliage – leaves of deciduous trees and needles of conifers. Because their effects are not systemic, the damage done by defoliators can usually be overcome by healthy, established trees. However, loss of foliage is still mild to moderately stressful on all trees, and if enough foliage is lost in one season, particularly in the new growth, it can spell disaster. The tree will have to use up significant amounts of reserve (stored) energy to make up for the loss of energy-producing foliage, and this loss of reserves can leave a tree vulnerable to many other stressors, both biotic and abiotic, especially if defoliation occurs several years in a row.

Defoliators are most commonly the larval (caterpillar or grub) forms of various moths, beetles, and sawflies. Because they are only feeding on foliage in the larval stage, their ability to damage trees is usually limited to a short time period in any growing season (2-6 weeks average). They are commonly broken down into 3 categories based on how they feed on foliage:

 

a. Leaf Chewers

The leaf chewing pests have the largest mouth-parts of defoliator larvae which allow them to eat large sections of leaf, sometimes devouring the entire leaf.

Common leaf chewers in southwestern Ontario include:

– Fall Webworm
– Gypsy Moth

  Fall Webworm Damage

 

b. Leaf Skeletonizers

The leaf skeletonizer pests are able to eat the soft outer tissues of foliage while leaving a skeletal network of veins behind, producing a very distinct visual effect.

Common leaf skeletonizers in southwestern Ontario include:

– Oak leaf skeletonizer
– Japanese beetle

  Japanese Beetle

 

c. Leaf Miners

The leaf miner pests are very small, tunnelling unseen between the upper and lower surfaces of leaves, feeding upon the succulent interior tissues, again producing a distinct visual effect.

Common leaf miners in southwestern Ontario include:

– Birch leafminer
– Cedar leafminer

  Cedar leafminer damage

 

2. Borers

The boring pests attack mainly the inner bark and wood, although all parts of the tree from roots to buds are affected. The main effects of boring insects are deformity and weakening of tissues, as well as serious damage to the transport tissues that allow trees to move water, nutrients, and sugars (cambium). If the transport tissues are sufficiently compromised, decline and death will occur quickly.

Common borers in southwestern Ontario include:

– Emerald Ash borer
– Bronze Birch borer

  Emerald Ash borer damage

 

3. Sucking Insects

These pests have leaching mouthparts which they use to extract cell sap either from foliage or directly from transport tissue (cambium). Their effects are usually lack of vitality, wilting, or discolouration, but in extreme cases they are capable of causing serious stress, decline, and even death of plant tissues.

Common sucking insects in southwestern Ontario include:

– Aphids
– Oystershell scale

  Aphid damage

 

4. Gall Makers

These pests cause trees to produce distinct, abnormal growths which usually envelope the insect. Despite their conspicuous appearance, most gall makers affect the aesthetic value of trees as opposed to their actual health. Once the gall has formed around the insect, it is quite protected, making control or treatment very difficult.

Common gall makers in southwestern Ontario include:

– Ash flower gall
– Oak & Hackberry gall

  Hackberry gall

 

5. Root Feeders

These pests live in the ground and feed on the succulent, non-woody portions of plant roots. They are seldom noticed and rarely cause the death of well-established trees. Seedlings or recently transplanted specimens with limited root systems are more susceptible to this type of injury.

Common root feeders in southwestern Ontario include:

– Black Vine weevil
– White Grubs

  White grub

 

 

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Tree Diseases and Disorders

Tree diseases may be defined as abnormal disruptions in the basic life processes of the plant, which may or may not be fatal. These disruptions are caused by parasitic agents (principally fungi but also bacterial or viral) or non-parasitic agents (nutrient imbalances, toxic chemicals, etc).

The presence of disease in trees is shown by the development of visible signs and symptoms. Signs are structures produced by parasitic agents (e.g. mushrooms, conks, fruiting bodies, etc). Symptoms are changes that occur as a result of injury (e.g. wilting leaves, discolouration, deformities, etc). Note that signs can only be produced by parasitic agents, while symptoms can be produced by both parasitic and non-parasitic agents.

Parasitic Diseases

The parasitic diseases of trees, of which most are caused by fungi, can be grouped into 2 main categories:

a. Foliar

Foliar diseases attack the foliage of the plant and are rarely transported inside the plant to other tissues. Their effect is similar to the defoliator pests in that the damage is rarely serious and trees can usually recover.

Common foliar diseases in southwestern Ontario include:

– Powdery mildew
– Anthracnose

  Powdery mildew

 

b. Systemic

Systemic diseases are able to move within the plant, affecting not only the foliage, but also the cambium and roots. Because of their ability to attack the entire plant, systemic diseases are the most difficult to treat. Due to a lack of systemic fungicides that are approved for commercial use, pruning is often the only treatment available to help combat these diseases. Pruning of affected tissues can help slow the progression of disease but is often not enough to stop it.

The effects of systemic disease are often quite severe and can leave trees stressed and susceptible to attack by other organisms or lead to the outright death of the plant.

Common systemic diseases in southwestern Ontario include:

– White Pine blister rust
– Dutch Elm disease

  Dutch Elm disease

 

Non-parasitic Diseases/Conditions

In addition to pest and disease issues, trees can also be negatively affected by a host of other interacting biological and climatic factors. These include: air and water pollution, flooding, drought, soil compaction, grade changes, nutrient imbalances, adverse weather, temperature extremes, and mechanical damage, such as cutting of roots for construction projects.

When a tree is in decline it is rarely the result of one single issue. Quite often, a stressed tree has been assailed by many negative factors, both biotic and abiotic, that have left it with an energy deficiency from which it is too weak to recover. For example, a tree growing in poor, compacted soil with inadequate drainage will have difficulty overcoming defoliation by insect pests. In attempting to regrow its leafy crown, the tree will have to use up a significant amount of its energy reserves which will leave it vulnerable to attack by a countless number of fungal agents. The end result of all this stress is usually dieback of stems or branches. Trees in advanced stages of dieback rarely recover, typically succumbing to invasion by secondary pests and diseases.

Because of this spiraling effect of stress and decline, the best prescription for landscape trees is prevention, through efforts to maximize the health and vitality of the plant. A healthy tree is far less likely to be attacked by pests and diseases and if it is attacked, generous amounts of stored energy will help ensure the best chance of recovery.

Common non-parasitic diseases/conditions in southwestern Ontario include:

– Chlorosis
– Dessication (Winter Browning)
– Road Salt damage
– Dieback of Hardwoods

  Chlorosis

  Road salt damage

 

 

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Climb High, Work Smart, Read More.
– TreeMuggs

 

I would love to hear from you. Please send all comments/questions/hatemail to patrick@educatedclimber.com

 

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This is the Tree ID book that I made for the first part of apprenticeship school years ago. It is by no means all of the trees that you will need to know, but it is a good starting point. This covers 48 common trees in this area. This book does not do justice to either bark or buds, so it may not be all that useful for winter identification.

The only way to properly learn your trees is out in the field. You will not learn that much from a book, regardless of how good the book is.

Tree ID Book - Southwestern Ontario- PDF
Download as PDF

 

For a comprehensive treatment of all the trees that grow in this area, please refer to “Trees In Canada” by John Laird Farrar. This book must be considered required reading.

 

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Climb High, Work Smart, Read More.
– TreeMuggs

 

I would love to hear from you. Please send all comments/questions/hatemail to patrick@educatedclimber.com

If you are just starting out, you are going to need to know a lot of basic terminology. This will be a good starting point, and I will continue to update it as need be.

 

General

a. Rigging – use of ropes to lower and control sections of tree to the ground.

b. Rigging System – interaction of all elements used for rigging including points in the tree, slings, hardware, rope, force angles, etc.

c. Piece – the section of tree being rigged.

d. Small Rigging – piece can be carried or dragged by one or two people once on the ground.

e. Big Rigging – pieces that are too heavy for two people to carry, must be cut up once on the ground.

f. Positive/Overhead Rigging – rigging point is above the piece, used whenever possible.

g. Negative Rigging – rigging point is below the piece, used in the absence of other options, always involves shock loading.

h. Shock Loading – mass coming to a short, sudden stop. Can multiply peak forces by 10X or more.

i. Tension wood – fibers are being pulled apart.

j. Compression wood – fibers are being squeezed together.

k. Leverage – bending force being exerted at a distance from a fulcrum.

 

Hardware

a. Tensile strength / Minimum Breaking Strength (MBS): the average breaking strength of a piece of equipment when pulled to failure under controlled conditions. Tensile strength is usually quoted in kN.

b. Kilonewton (kN): approximately 225 lb.

c. Minimum strength: as defined by safety legislation and regulations, life safety gear is required to have a tensile strength of at least 5000 lb (usually rounded up to 23 kN).

d. Working Load Limit (WLL): expressed as a fraction of the tensile strength, this is the maximum load that the equipment is rated for over a large number of cycles. Standards are rigging gear 5:1, climbing gear 10:1. For example, if a rigging line is rated for 5000 lb and the working load limit is 5:1, that means you can consistently load it with 1/5 of its tensile strength (i.e. 1000 lb). For a climbing line rated at 5000 lb, you can consistently load it with 1/10 of its tensile strength (i.e. 500 lb).

e. Cycles to Failure: Ropes and slings can only be exposed to heavy loads so many times before they eventually fail. Adherence to WLL guidelines will ensure long life for your equipment, this is why it is so important to know the history of your gear.

f. Static Rope: very low stretch (0.5-1.5% range). Rarely used in rigging.

g. Semi-static Rope: low stretch (1.5-4% range). This is standard arborist rope used for climbing and rigging.

h. Dynamic Rope: very high stretch (5-20% range). Used in mountain climbing to catch a lead climber during a fall to minimize injury.

 

_____________________________________________

Climb High, Work Smart, Read More.
– TreeMuggs

 

I would love to hear from you. Please send all comments/questions/hatemail to patrick@educatedclimber.com