Insects Affecting Bark

IMPORTANT AND COMMON INSECTS AFFECTING BARK

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Lepidoptera

*Sequoia pitch moth,
Synanthedon sequoiae
*Douglas-fir pitch moth
Synanthedon novaroensis
(Lepidoptera: Sesiidae)
Pitch mass on Lp
Synanthedon novaroensis
Larvae Stage
Host: Boles of pines and spruce
Host: Boles of pines, spruce Douglas-fir
The white, cream-coloured, or pinkish larvae of these insects feed on phloem of live trees, causing resin exudation
Damage: These moths are called clearwing moths because of a lack of scales on much of the wings. Very large pitch masses, often associated with injury, Cronartium rust cankers, or Endocronartium galls on bole. Larvae tend to mine horizontally. Repeated attack can lead to breakage. Not a severe problem in natural stands, but can be significant in ornamental and high value situations, e.g., seed orchards and provenance trials.

Western pine moth,
Dioryctria cambiicola
(Lepidoptera: Pyralidae)
WPM Adult
WPM Attack rust canker
Host: Lodgepole and ponderosa pine. Damage: Causes pitch masses on the bole at Cronartium cankers. See also Twig and Branch Insects.

Coleoptera

Bark Beetles

(Coleoptera:Scolytidae)

This group includes some of the most serious forest pests. Adult beetles bore into the phloem, where they construct a tunnel, or gallery. Eggs are laid along the sides of the tunnel, and the larvae mine in the phloem. Many species have symbiotic fungi. Some species are also associated with root pathogens.

The Bark Beetle Management Guidebook is an additional information source.

Mountain pine beetle, Dendroctonus ponderosae* Mortality of Lp MB gallery Beetle proofing	Host:Primarily lodgepole pine, other pines.	Damage: Causes widespread mortality in mature and overmature stands throughout the range of lodgepole pine. Natural agent of lodgepole pine mortality in the absence of fire. Management: Sanitation logging, baiting and cutting, single tree removal or lethal trap trees, reducing stand susceptibility by partial cutting.
Spruce beetle, Dendroctonus rufipennis* Mortality of Sx SB gallery	Host: Spruce	Damage: Causes widespread mortality in mature spruce stands continent wide. Normally confined to dead or dying trees, preferably down trees. Population buildup occurs following blowdown and logging. Outbreaks can be severe. Management: Sanitation logging, lethal and conventional trap trees, baiting and cutting.
Douglas-fir beetle, Dendroctonus pseudotsugae* Mortality of D-fir Douglas-fir bettle attack on a felled tree	Host: Douglas-fir, rarely western larch	Damage: Causes locally severe mortality in overmature and stressed Douglas-fir in the dry interior, and occasionally in wetter areas. This bark beetle prefers dead trees. Often two flights in the interior, one in early spring, one in mid- to late summer. Outbreaks in British Columbia tend to be patchy and of short duration, but are significant because of the value of the trees. Management: Conventional trap trees, sanitation harvesting, partial cutting. Note: The distribution map in the guidebook is incorrect. Douglas-fir beetles occur throughout the range of its host.
Western pine beetle, Dendroctonus brevicomis*	Host: Ponderosa pine	Damage: Causes occasional mortality to ponderosa pine in B.C. Major pest in western United States, where it can have multiple, overlapping generations (3 or more). Management: Sanitation harvesting.
Red turpentine beetle, Dendroctonus valens Pitch tube	Host: Pines.	Damage: Widely distributed. Our largest Dendroctonus species. Rarely causes mortality, but commonly associated with other species on ponderosa pine and other pines. Large reddish pitch tubes at base of trees characteristic.
Lodgepole pine beetle, Dendroctonus murrayanae	Host: Lodgepole pine.	Damage: Large pitch tubes low on bole of injured or stressed trees, e.g., at cutblock edges. Also common on stumps and sometimes on felled or windthrown trees. Not important pest.

*Pine engraver
Ips pini
Host: Pines Damage: Transcontinental, normally secondary species. Usually associated with mountain pine beetle, occupying the upper bole. May kill trees near slash piles, or when trees are stressed. Significant problem in intermountain region of the U.S. after thinning operations.
Note: Several other Ips species may be abundant on pine. E.g. Ips mexicanus and Ips latidens.
Management: Reduce breeding material, e.g., slash.

*Northern spruce engraver,
Ips perturbatus
Host: Spruce Damage: Normally secondary species, found on spruce in association with the spruce beetle. It has caused widespread mortality of spruce in Alaska.
Note: Several other Ips species may be found on spruce as well. E.g. Ips tridens and Ips borealis.

Fir engraver,
Scolytus ventralis
Host: Abies spp. Damage: Occasionally serious on grand fir in dryer locations, e.g., Kootenays and locally in dry coastal areas. Severe pest in parts of U.S., particularly on off-site planted firs.

*Smaller European elm bark beetle,
Scolytus multistriatus
Host: Elms Damage: Introduced species vectoring Dutch elm disease. Spreading west, but has yet to be introduced to B.C. In areas where it is established, American elms have virtually been eliminated.
Links: Colorado State National Parks / University of Toronto

*Western balsam bark beetle,
Dryocoetes confusus
WBBB Mortality
WBBB Galleries
Host: Subalpine fir Damage: Causes scattered mortality of subalpine fir over large areas. Has not been given much attention due to low utilization of host tree, but becoming an increasing concern.
Management: Sanitation harvesting, baiting and cutting.

Four-eyed spruce beetle,
Polygraphus rufipennis
Host: Spruce Damage: Small bark beetle often associated with the spruce beetle. Can cause mortality.

*Pityogenes plagiatus knechteli Host: Pines Damage: Small bark beetle that can cause mortality in thinned or stressed immature lodgepole pine. Normally associated with Ips pini.

*Larger European pine shoot beetle,
Tomicus piniperda
Host: Pines Damage: Recently introduced around the Great Lakes. Breeds in dead or dying pine. Flies extremely early, thereby displacing native pine bark beetles like Ips pini. Causes damage by maturation feeding in pine shoots. Also concern that it may become a primary species on new hosts.

Silver fir beetle,
Pseudohylesinus sericeus
Host: Abies spp Damage: Rarely serious, but have been known to cause widespread mortality of Abies spp. along with the Fir root bark beetle, Pseudohylesinus granulatus. The silver fir beetle is also found on western hemlock and Douglas-fir, often in association with root pathogens.

*Hylastes & Hylurgops

Bark Beetles

** The following three beetles are often vectors of disease organisms, e.g. black stain root disease.

The following beetles are also included in the Root Insects pathonotes

Hylastes nigrinus	Hosts: conifers	Damage: Adults feed on fine roots of large, dead trees, and on roots of small weakened trees, occasionally killing trees through girdling. Eggs are laid on roots.
Hylurgops porosus	Hosts: Conifers	Damage: Common throughout the west. Breeds in lower bole and root collar.
Hylurgops subcostulatus	Hosts: Conifers	Damage: Attacks pines throughout the west. Called "sour sap beetles", due to their habit of breeding under the bark of wet, fermenting conifers, e.g. roots or tree boles in contact with the ground.

Homoptera

Insects with sucking mouthparts. They feed on the juices of plant cells

*Balsam woolly adelgid,

Adelges piceae

Host: Abies spp.

Damage: Introduced from Europe. Causes mortality in Abies species by triggering a wide spread hypersensitive response in the host. Currently spreading north and east in British Columbia. Strict quarantines apply.

Smaller European elm bark beetle, Scolytus multistriatus*	Host: Elms	Damage: Introduced species vectoring Dutch elm disease. Spreading west, but has yet to be introduced to B.C. In areas where it is established, American elms have virtually been eliminated. Links: Colorado State National Parks / University of Toronto
Western balsam bark beetle, Dryocoetes confusus* WBBB Mortality WBBB Galleries	Host: Subalpine fir	Damage: Causes scattered mortality of subalpine fir over large areas. Has not been given much attention due to low utilization of host tree, but becoming an increasing concern. Management: Sanitation harvesting, baiting and cutting.
Four-eyed spruce beetle, Polygraphus rufipennis	Host: Spruce	Damage: Small bark beetle often associated with the spruce beetle. Can cause mortality.
*Pityogenes plagiatus knechteli	Host: Pines	Damage: Small bark beetle that can cause mortality in thinned or stressed immature lodgepole pine. Normally associated with Ips pini.
Larger European pine shoot beetle, Tomicus piniperda*	Host: Pines	Damage: Recently introduced around the Great Lakes. Breeds in dead or dying pine. Flies extremely early, thereby displacing native pine bark beetles like Ips pini. Causes damage by maturation feeding in pine shoots. Also concern that it may become a primary species on new hosts.
Silver fir beetle, Pseudohylesinus sericeus	Host: Abies spp	Damage: Rarely serious, but have been known to cause widespread mortality of Abies spp. along with the Fir root bark beetle, Pseudohylesinus granulatus. The silver fir beetle is also found on western hemlock and Douglas-fir, often in association with root pathogens.