Forest Insect

& Disease

Leaflet 2

Revised May 2009

U.S. Department of Agriculture • Forest Service

Mountain Pine Beetle

Ken Gibson1, Sandy Kegley2, and Barbara Bentz3

Introduction

The mountain pine beetle, 

Dendroctonus ponderosae Hopkins 

(Coleoptera: Curculionidae, 

Scolytinae) is a member of a group 

of insects known as bark beetles. 

Its entire life cycle is spent beneath 

the bark of host trees, except when 

adults emerge from brood trees and 

fly in search of new host trees.

Mountain pine beetles can 

reproduce in all species of pine 

within their range. Outbreaks often 

develop in dense stands of largediameter (>8 inches), older (>80 

years-old) lodgepole pine and dense 

stands of mid-sized (8-12 inches 

diameter) ponderosa pine. When 

weather is favorable for several 

consecutive years, severe outbreaks 

can occur in high-elevation stands 

of whitebark and limber pine. 

Widespread outbreaks develop 

over several years and can result 

in millions of dead trees. Periodic 

losses of high-value, mature sugar and 

western white pine are less widespread, 

but also serious.

Extensive tree mortality associated 

with a mountain pine beetle outbreak 

can significantly influence successional 

pathways and forest community 

Mountain pine beetle-killed whitebark pine in Yellowstone 

National Park, 2004. 

1

USDA Forest Service, Forest Health Protection, Missoula, MT.

2

USDA Forest Service, Forest Health Protection, Coeur d’Alene, ID.

3

USDA Forest Service, Rocky Mountain Research Station, Logan, UT.
2

composition. Many ecosystems 

have become dependent on 

mountain pine beetle disturbance 

events and subsequent wildfire 

for forest renewal. However, 

outbreaks can also deplete 

commercial pine forests. Late 

successional tree species that are 

less commercially valuable, such 

as subalpine fir, often replace 

more valuable pioneer species, 

such as lodgepole pine, that have 

been killed by mountain pine 

beetle. Many wildlife species 

may benefit from mountain pine 

beetle outbreaks, including birds 

that feed on developing larvae 

and nest in dead trees. However, 

in the short-term, composition 

and distribution of others, such 

as elk and deer, may be affected 

by a reduction in hiding and 

thermal cover. Other forest 

processes such as water yield and 

wildfire extent and severity can 

also be affected in the long- and 

short-term by tree mortality 

associated with mountain pine 

beetle outbreaks. 

Range and Hosts

Mountain pine beetles are native 

to pine forests of western North 

America. They are found from 

the Pacific Coast east to the Black Hills of 

South Dakota, and from central British 

Columbia and western Alberta to northern Baja California, Mexico (Figure 1). 

Their habitat ranges from near sea level in 

British Columbia, to 11,000 feet in southern California.

Major hosts of mountain pine beetle 

include lodgepole, ponderosa, western 

white, sugar, limber and whitebark pines. 

All pine species within in their range, 

including Coulter, foxtail, pinyon, and 

bristlecone pines, can also be infested 

and killed. Scotch and Austrian pines, 

introduced into North America as ornamentals, Christmas trees and/or forest 

plantations, are also susceptible to attack. Douglas-fir, true firs, western larch, 

incense-cedar and western hemlock are 

occasionally attacked, but because they 

are not true hosts, broods rarely develop. 

Recently, mountain pine beetle has been 

found producing viable brood in spruce. 

Attacks on trees other than pines usually 

only occur when nearby pines are heavily 

infested and beetle population levels are 

high.

Evidence of Infestation 

Mountain pine beetle typically initiates attacks on the lower 15 feet of a tree 

bole, although the crown of large trees, 

particularly sugar pine, may be attacked 

Figure 1. The range of mountain pine beetle generally follows 

its major host pine species throughout western North America 

(shown in green). Current range of mountain pine beetle 

extends from northern Baja California, Mexico and southern 

Arizona, US to central British Columbia, Canada. In recent 

years, mountain pine beetle outbreak populations (shown in 

red) have been found further north into British Columbia and 

east into Alberta than had been observed in historical records, 

including an outbreak in 1985.
3

first. During outbreaks, a tree is generally 

“mass-attacked” and killed by girdling of 

the phloem (i.e., layers of cells just inside 

the bark that transport photosynthate 

within the tree) by beetles of a single generation. When population levels are low, 

partial attacks around the bole’s circumference referred to as ”strip attacks,” may result in two or more generations of beetles 

before the tree is killed. Strip–attacked 

trees may survive for many years.

Signs of a mountain pine beetle attack include “pitch tubes” which are made when 

female beetles bore into the tree’s bole. On 

successfully attacked trees, pitch tubes are 

cream to dark-red masses of resin mixed 

with phloem boring dust, and are about 

one-fourth to one-half inch in diameter. 

When beetles are not present in sufficient 

numbers to overcome a tree’s defenses, 

enough resin is produced at the attack site 

to “pitch out” beetles as they attempt to 

bore into the inner bark. Pitch tubes on 

unsuccessfully attacked trees are larger, 

three-fourths to one-inch in diameter, 

generally generally lighter in color, and 

widely scattered over the trunk (Figure 2). 

In addition to pitch tubes, successfully 

infested trees will have dry, reddish-brown 

boring dust, similar to fine sawdust, in 

bark crevices along the tree bole and 

around the tree base (Figure 3). Infested 

trees may also have boring dust but no 

apparent pitch tubes. These trees, referred 

to as “blind attacks,” are more common 

during periods of drought when trees may 

be stressed and capable of producing little 

pitch.

Needles on successfully infested trees 

begin changing color several months to a 

Figure 2: Unsuccessful mountain pine beetle 

attack—commonly called a “pitchout.” 

Figure 3: Pitch tubes and boring dust—

indicative of a successful mountain pine beetle 

attack in lodgepole pine. 

Figure 4. Fading mountain pine beetle-killed 

lodgepole pines. Trees generally fade 8-10 

months after being attacked. 
4

year after attack. In unusually dry years, 

foliage may begin to fade within a few 

weeks. Needles change from green to yellowish green, then sorrel, red, and finally 

rusty brown (Figure 4, see page 3). Fading 

often begins in the lower crown and progresses upward in lodgepole pine, but may 

vary somewhat with other hosts. In largediameter, tall sugar pines, for example, 

upper crown fading may be the first sign 

of an infestation.

Mountain pine beetle is associated with 

several fungal species including Ophiostoma montium and Grosmannia clavigera. 

Attacking beetles carry spores of the fungi 

on their bodies and in specialized structures called mycangia. Fungi are inoculated into the tree by adult beetles, and developing larvae and new adults obtain vital 

nutrients by feeding on fungal structures 

that spread throughout the phloem and 

sapwood. In addition to providing nutrients for developing brood, fungi can also 

alter patterns of water and resin flow in the 

tree, aiding in tree death. One to several 

months after the tree is infested, the sapwood discolors to a bluish tint caused by 

these “bluestaining” fungi (Figure 5). 

Woodpeckers often feed on developing 

or overwintering larvae beneath the bark, 

and in doing so can make holes in thick 

barked trees such as ponderosa pine, or 

may completely remove the bark from 

thinned bark trees such as lodgepole and 

whitebark pine. These signs, plus resulting 

piles of bark flakes around a tree base, can 

also be evidence of mountain pine beetle 

infestation.

Life History

Beetles develop through four stages: egg, 

larva, pupa, and adult. Except for a few 

days during the summer, when adults 

emerge from brood trees and fly to attack 

new host trees, all life stages are spent beneath the bark.

Temperature has a significant influence on 

mountain pine beetle development and 

survival. Populations across the beetle’s 

wide range have adapted to local temperature regimes, resulting in variability in the 

time required to complete a generation 

as well as timing of individual life-stage 

development. In low elevation stands 

and in warm years, mountain pine beetle 

require one year to complete a generation. 

At higher elevations, where summers are 

typically cooler, life cycles may vary from 

one to two years. 

Female beetles initiate attacks. During the 

process of chewing into the inner bark 

and phloem, aggregating pheromones are 

released attracting hundreds of male and 

female beetles to the same tree within a 

few days. More attacking beetles produce 

more attractant pheromones, resulting in a mass attack that overcomes the 

tree’s defenses. Male beetles also produce 

pheromones, including anti-aggregating 

pheromones that help regulate the number 

of attacks on an individual tree to prevent 

overcrowding. This dynamic combination 

of pheromones also results in attacks on 

adjacent live trees, producing groups of 

dead trees across a landscape.

Mating occurs under the bark, after which 

females construct straight, vertical egg 

galleries. Packed with boring dust, these 

galleries are mostly in the phloem, or 

inner bark, although they often slightly 

Figure 5. Blue-stained sapwood of a mountain 

pine beetle-killed tree. 
5

score the sapwood. Galleries may range 

from 4-48 inches in length, depending on 

attack density, but average about 10 inches 

(Figure 6).

Tiny, pearl-white eggs are laid in niches 

along both sides of egg galleries. Timing 

of egg laying is dependent on temperature 

and geographic location, but typically occurs from late June to late August. Eggs 

hatch in 10-14 days, although they may 

take longer in cooler weather (Figure 7).

Eggs may also be laid in late spring by 

females that survived winter. Surviving 

females and males may either re-emerge 

and attack new trees or merely extend egg 

galleries in the same tree where they overwintered. 

Larvae are legless white grubs with brown 

heads that feed in the phloem, constructing galleries that extend at right angles 

to the egg gallery. Development through 

four larval stages (instars) is temperature 

dependent and therefore highly variable 

from year to year and site to site. The 

final larval instar excavates an oval cell 

where pupation occurs and the new adult 

is formed. New, immature adults spend a 

period of time maturation feeding on fungal spores and associated tree tissue before 

emerging. When several feeding chambers 

coalesce, adults may be found in groups, 

and one or more beetles often emerge 

from the same exit hole. Within one or 

two days of emerging, adults seek out and 

attack new trees, to resume the yearly cycle 

(Figures 8, 9, 10).

Factors Affecting Outbreaks 

Mountain pine beetle populations can 

exist at low levels in pine ecosystems for 

decades infesting and killing stressed 

trees, resulting in scattered and often insignificant levels of tree 

mortality. Eruption to an 

outbreak population and 

subsequent widespread 

tree mortality are dependent on a number of factors, including favorable 

climatic and stand condiFigure 6. Mountain pine beetle egg 

and larval galleries. 

Figure 7. Mountain pine beetle 

adult and eggs in egg gallery. 

Figure 8. Mountain pine beetle 

larvae in feeding galleries. 

Figure 9. Larvae transform to 

pupae within cells constructed 

at end of feeding gallery. 

Figure 10. “Callow” or 

immature adults darken before 

emerging to complete life cycle. 
6

Figure 11. Woodpecker feeding on overwintering larvae 

typically has little effect on outbreak populations. 

tions as well as proximity to an existing 

beetle population. 

Temperature. Mountain pine beetle 

population success is influenced by temperature in several ways. Cool temperatures may retard development, resulting 

in longer lifecycles and/or a disruption 

of critical timing of summer emergence 

necessary for a coordinated and successful 

mass attack. Also, excessively warm temperatures could speed up development and 

similarly disrupt emergence timing. Cold 

temperatures can directly affect mountain 

pine beetle survival. Although mountain 

pine beetles have mechanisms that enable 

survival in sub-freezing conditions, unseasonably low temperatures for extended 

periods of time in winter can cause excessive mortality in all lifestages. In particular, dramatic temperature drops in autumn 

and spring can result in death of many 

individuals. 

Tree Resistance. To reproduce, mountain 

pine beetles must successfully locate 

and colonize suitable hosts. Colonization requires overcoming tree defenses 

and can only be accomplished by 

recruitment of a critical minimum 

number of beetles, which varies with 

changes in host vigor. When the number of mountain pine beetles emerging 

to attack new trees is low, healthy trees 

may produce sufficient resin to prevent successful attacks. Beetles either 

drown in toxic resins as they bore into 

the inner bark, or abandon the tree. 

If a large number of beetles are available to attack a tree within a short time 

period, even a relatively healthy tree 

can be overcome. Several factors can 

influence tree resistance including precipitation, temperature, stand density, 

and pathogen infections. 

Predators and Parasites. Nematodes, 

worm-like internal parasites, can hinder or prevent egg production. Other 

nematodes feed on eggs after they are 

laid.

A dolichopodid fly and two species of 

checkered beetles are common predators 

of both adults and immature beetles. Parasitic wasps are also prevalent in mountain 

pine beetle populations. All may reduce 

beetle populations substantially in individual trees, but none have been shown 

to significantly influence mountain pine 

beetle populations during outbreaks.

Many species of woodpeckers feed heavily 

on developing or overwintering larvae. In 

their search for larvae, woodpeckers make 

holes or large openings in the bark causing 

the remaining bark to dry more quickly, 

subsequently killing additional larvae. 

Woodpeckers can significantly influence 

beetle mortality during endemic populations, but are not considered important in 

regulating outbreaks (Figure 11).

Competition. Mountain pine beetle larvae compete for food and space not only 

with each other, but with larvae of other 

insect species. For example, larvae of 
7

wood boring beetles, which are also found 

within the inner bark, can canabilize large 

numbers of mountain pine beetle brood. 

Other bark beetles with faster development time and/or attack timing can utilize 

the food resource ahead of slower developing mountain pine beetle.

Stand and Landscape Characteristics. 

Weather, host trees and community associates are important to rapid expansion 

of mountain pine beetle populations. 

Spread of a population across a landscape, 

however, is also dependent on a variety of 

stand and landscape characteristics that 

may differ by ecosystem. Stands with characteristics susceptible to mountain pine 

beetle population outbreaks are referred 

to as high “hazard.” Generally, adequate 

food (host trees), of a suitable size and age 

are required across large areas for a widespread outbreak to occur. 

Mountain pine beetle outbreaks in lodgepole pine develop and are sustained in areas with an average age >80 years, average 

tree diameter (at breast height) >8 inches, 

stand stocking between 300-600 trees per 

acre, and at an elevation/latitude combination suitable for beetle survival (Figure 

12). When the majority of larger-diameter 

lodgepole pines have been infested and 

killed, beetles tend to infest smaller and 

smaller trees. Phloem is thinner and 

dries more quickly in such trees and fewer 

offspring are produced. Once the food 

supply has been exhausted and/or weather 

becomes unfavorable, populations decline. 

In second-growth ponderosa pine stands 

in the Black Hills and Rocky Mountains, 

highly susceptible stands are generally 

those that are densely stocked (i.e., for 

average stand diameter of 10-12 inches, 

>150 square feet basal area per acre), have 

an average diameter >10 inches, and are 

even-aged and single-storied. The role of 

mountain pine beetle in ponderosa pine 

stands at some western locations may be 

secondary to that of western pine beetle 

(D. brevicomis LeConte), particularly in 

larger diameter (>12 inches in diameter) 

trees. Occasionally, mountain pine beetle 

infestations are confined to small-diameter 

(<12 inches diameter) ponderosa pines 

with single trees or small groups of trees 

being killed. In all cases, a stand may 

remain uninfested for decades until conditions are suitable for beetle population 

growth. 

Management Options

Management options for mountain pine 

beetle populations are scale and time-dependent. Options include: 1) short-term 

prevention techniques, aimed at manipulating beetle populations, 2) long-term 

prevention techniques targeted 

at the stand and 

landscape, and 3) 

restoration of affected landscapes. 

Short-term 

Prevention

Insecticides. Preventive treatments, 

applied before 

trees are infested 

Figure 12. A “high-hazard” lodgepole pine stand, very susceptible to mountain by beetles, are an 

pine beetle infestation. 
8

Figure 13. Preventive treatments can successfully 

protect susceptible hosts from mountain pine 

beetle attacks. 

effective use of insecticides to protect individual high-value trees. Useful in campgrounds, around home sites, or to protect 

valuable seed-producing trees, preventive 

sprays can effectively, efficiently, and economically protect trees from beetle attack. 

However, if stand conditions contributing 

to outbreaks are not changed, periodic 

treatments will be necessary as long as epidemics exist in the area 

(Figure 13).

Insecticides are registered and periodically 

reviewed by the U.S. Environmental Protection Agency. Persons contemplating 

the use of insecticides should contact pest 

control or forest health professionals to 

ensure proper use.

Pheromones. As noted previously, beetles 

produce both aggregative and antiaggregative pheromones that are used to 

manipulate their populations to their advantage. Many of these “message-bearing” 

chemicals have been identified, and their 

production synthesized. Forest health 

professionals and resource managers can 

use these chemicals to manipulate beetle 

populations to our advantage.

Synthesized aggregative pheromones can 

be used as tree “‘baits” and in traps to attract and contain small spot infestations, 

thus reducing probability of spread into 

nearby susceptible stands. To be effective, 

aggregative pheromones must be used 

in combination with removal of infested 

trees. Anti-aggregative pheromones, such 

as verbenone, show promise in preventing 

attacks on high-value sites. Both strategies 

may be used to manipulate beetle populations to our advantage until silvicultural 

treatments can be implemented to reduce 

stand susceptibility, or beetle populations 

naturally return to endemic levels (Figure 

14).

Synthetically produced pheromones are 

registered and periodically reviewed 

by the U.S. Environmental Protection 

Figure 14. Verbenone can be an effective 

preventive treatment in some situations. 
9

Agency. Persons contemplating the use of 

pheromones should contact a forest health 

professional to ensure proper use. Inappropriate use can result in unintended tree 

mortality. 

Long-term Prevention

Stand conditions associated with mountain pine beetle outbreaks have been 

quantified for several pine types. Several 

hazard rating models are available for 

identifying stands that are most likely to 

be infested, and to predict expected levels 

of beetle-caused tree mortality should an 

outbreak occur. Although less certain, 

models also have been developed for predicting stand risk, an estimate of when a 

stand will become infested. Risk models 

include a measure of the proximity of an 

active mountain pine beetle population. 

Resource managers can use available models to incorporate mountain pine beetle 

information into planning processes, so 

appropriate action can be taken prior to 

outbreak initiation. 

Silviculture. Silvicultural measures, 

such as thinning (Figure 15), have been 

shown to minimize mountain pine beetlecaused tree mortality in some lodgepole 

and ponderosa pine stands if performed 

prior to outbreak initiation. Opening the 

stand through thinning influences beetle 

populations by 1) changing microclimate 

and wind patterns within the stand, 2) allowing beetle-produced pheromones to 

dissipate through opened crowns, and 3) 

providing more growing space, nutrients, 

and water for remaining trees. 

Patch-cutting in lodgepole pine landscapes 

creates a mosaic of age and size classes, 

which reduces acreage of lodgepole pine 

that will be highly susceptible to mountain 

pine beetle attack at any one time. Where 

clear- or patch-cutting is not an option, 

selective harvesting can help reduce beetle-related damage. Susceptible trees can 

be removed selectively in riparian zones, 

along roads, in campgrounds, and in scenic vistas.

Salvage can retrieve timber that would 

otherwise be lost, and if infested trees are 

removed and disposed of before beetles 

emerge, some reduction in beetle populations will be realized. However, salvage 

logging of infested trees, while a large 

outbreak is underway, is generally not effective for reducing subsequent levels of 

mountain pine beetle-caused tree mortality. Additionally, beetle-infested trees and 

resultant snags and woody debris are important for many species of wildlife, nutrient recycling and tree regeneration.

Silvicultural strategies to reduce stand 

susceptibility to mountain 

pine beetle outbreaks in 

host species other than 

lodgepole and ponderosa 

pines have not been developed.

Prescribed fire is an additional option for altering 

stand density to reduce 

overall susceptibility to 

mountain pine beetle attacks. However, sublethal 

heating of critical plant 

tissue during prescribed 

burns can stress residual 

trees, which then may beFigure 15. Silvicultural treatments offer the best long-term means of 

protecting susceptible stands from mountain pine beetle infestation. 
10

come more susceptible to bark beetle attack. Care should be taken to reduce firecaused injury to desirable trees, especially 

in thin-barked species.

Restoration 

Forest landscapes comprised of diverse 

tree species, ages, and size classes may be 

less susceptible to widespread levels of 

mountain pine beetle-caused tree mortality. Restoration efforts emphasizing 

diversity, especially at landscape scales, are 

viable management strategies. Such efforts 

will require an understanding of host-site 

relationships, and may entail manipulation 

of stand density and species composition 

through silvicultural means.

Additional Information

Private landowners can get more information about mountain pine beetle ecology 

and management from local Cooperative Extension agents, State agricultural 

experiment stations, county Extension 

offices, and Forest Health Protection staffs, 

USDA Forest Service. Federal or State resource managers should contact the Forest 

Health Protection office—either Federal or 

State—in their area.

Acknowledgments

This is a revision of “Mountain Pine 

Beetle, Forest Insect & Disease Leaflet 

2” written by Gene D. Amman, Mark D. 

McGregor, and Robert E. Dolph, Jr., 1985. 

Critical reviews were provided by: Chris 

Fettig, (USDA Forest Service, PSW), Sheri 

Smith (USDA Forest Service, R-5), and 

Steve Munson (USDA Forest Service, R-4) 

Assistance with layout and publication was 

provided by: Michael Hamel, Visual Information Specialist

Photos:

Barbara Bentz (Figure 1)

Larry Stipe (USDA Forest Service, R-4)

(Figure 13)

Sandy Kegley (Figures 2, 3, 4, 11, and 14)

Ken Gibson (Cover photo, Figures 12 

and 15)

USDA Forest Service Files (Figures 5, 6, 7,

8, 9, and 10)

Suggested Reading

Amman, G.D.; McGregor, M.D.; Cahill, D.B.; 

Klein, W.H. 1977. Guidelines for reducing 
11

losses of lodgepole pine to the mountain pine 

beetle in unmanaged stands in the Rocky 

Mountains. Gen. Tech. Rept. INT-GTR-36. 

Ogden, UT: USDA Forest Service, Intermountain Forest & Range Experiment Station. 19 p. 

Amman, G.D.; Cole, W.E. 1983. Mountain pine 

beetle dynamics in lodgepole pine forests. Part 

II: Population dynamics. Gen. Tech. Rept. INTGTR-145. Ogden, UT: USDA Forest Service, 

Intermountain Forest & Range Experiment 

Station. 59 p. 

Bentz, B.J.; Logan, J.A.; Amman, G.D. 1991. 

Temperature dependent development of the 

mountain pine beetle (Coleoptera: Scolytidae), 

and simulation of its phenology. Canadian Entomologist 123:1083-1094.

Bentz, B.J.; Kegley, S.; Gibson, K.; Their, R. 

2002. A test of high-dose verbenone for standlevel protection of lodgepole and whitebark 

pine from mountain pine beetle (Coleoptera:

Curculionidae:Scolytinae) attacks. Journal of 

Economic Entomology 96:1614-1621.

Bollenbacher, B.; Gibson, K.E. 1986. Mountain 

pine beetle: A land manager’s perspective. Forest Pest Management Report 86-15. Missoula, 

MT. USDA Forest Service, Northern Region. 

5 p. 

Cole, W.E.; Amman, G.D. 1980. Mountain 

pine beetle dynamics in lodgepole pine forests. 

Part I: Course of an infestation. Gen. Tech. 

Rept. INT-GTR-89. Ogden, UT. USDA Forest 

Service, Intermountain Forest & Range Experiment Station. 56 p. 

Fettig, C.J.; Allen, K.K.; Borys, R.R.; Christopherson, J.; Dabney, C.P.; Eager, T.A.; Gibson, 

K.E.; Hebertson, E.G.; Long, D.F.; Munson, 

A,S,; Shea, P.J.; Smith, S.L.; Haverty, M.I. 2006. 

Effectiveness of bifenthrin (OnyxTM) and carbaryl (Sevin® SL) for protecting individual, 

high-value trees from bark beetle attack (Coleoptera: Curculionidae: Scolytinae) in the 

western United States. Journal of Economic 

Entomology 99:1691-1698.

Fettig, C.J.; Klepzig, K.D.; Billings, R.F.; Munson, A.S.; Nebeker, T.E.; Negrón, J.F.; Nowak, 

J.T. 2007. The effectiveness of vegetation management practices for prevention and control 

of bark beetle outbreaks in coniferous forests of 

the western and southern United States. Forest 

Ecology and Management 238:24-53.

Gibson, K.E.; Bennett, D.D. 1985. Carbaryl prevents attacks on lodgeple pine by the mountain 

pine beetle. Journal of Forestry 83:109-112. 

Gibson, K.; Skov, K.; Kegley, S.; Jorgensen, C.; 

Smith, S., Witcosky, J. 2008. Mountain pine 

beetle impacts in high-elevation five-needle 

pines: current trends and challenges. FHP Report R1-08-020. Missoula, MT. USDA Forest 

Service, Forest Health Protection, 32 p.

Kegley, S.; Gibson, K. 2009. Individual tree tests 

of verbenone and green-leaf volatiles to protect 

lodgepole, white bark, and ponderosa pines, 

2004-2007. FHP Report 09-03, Missoula, MT. 

USDA Forest Service, Forest Health Protection, 

12 p.

McGregor, M.D.; Amman, G.D.; Schmitz, R.F.; 

Oakes, R.D. 1987. Partial cutting lodgepole 

pine stands to reduce losses to the mountain 

pine beetle. Canadian Journal of Forest Research 17:1234-1239.

McGregor, M.D.; Cole, D.M. (editors). 1985. 

Integrating management strategies for the 

mountain pine beetle with multiple-resource 

management of lodgepole pine forests. Gen. 

Tech. Rept. INT-GTR-174. Ogden, UT. USDA 

Forest Service, Intermountain Forest & Range 

Experiment Station. 68 p. 

Negrón, J.F.; Allen, K.K.; Cook B.; Withrow, J.R. 

Jr. 2008. Susceptibility of ponderosa pine, Pinus ponderosa (Dougl. ex Laws.), to mountain 

pine beetle, Dendroctonus ponderosae Hopkins, 

attack in uneven-aged stands in the Black Hills 

of South Dakota and Wyoming USA. Forest 

Ecology and Management 254:327-334.

Rasmussen, L.A. 1976. Keys to common parasites and predators of the mountain pine beetle. 

Gen. Tech, Rept. INT-GTR-29. Ogden, UT. 

USDA Forest Service, Intermountain Forest & 

Range Experiment Station. 4 p.

Safranyik, L.; Wilson, B. (eds). 2006. The 

mountain pine beetle: A synthesis of biology, 

management, and impacts on lodgepole pine. 

Natural Resources Canada, Canadian Forest 

Service, Pacific Forestry Centre, Victoria, B.C. 

304 p. Available electronically (free) at: http://

bookstore.cfs.nrcan.gc.ca/

Samman. S.; Logan, J. 2000. Assessment and 

response to bark beetle outbreaks in the Rocky 

Mountain area: Report to Congress from Forest 

Health Protection, Washington Office. Gen. 

Tech. Rept. RMRS-GTR-62. Washington, D.C. 
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States have restrictions on the use of certain pesticides. Check your State and local regulations. Also, because 

registrations of pesticides are under constant review by the Federal Protection Agency, consult your county 

agricultural agent or State extension specialist to be sure the intended use is still registered.

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mountain pine beetles in the Black Hills. Res. 

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J.B. 2007. The influence of partial cutting on 

mountain pine beetle-caused mortality in Black 

Hills ponderosa pine. Res. Pap. RMRS-RP-68. 

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Schwandt, J. 2006. Whitebark pine in peril: A 

case for restoration. FHP Report, R1-06-28. 

Coeur d’Alene, ID. USDA Forest Service, Forest Health Protection. 20 p.

Six, D.L. 2003. A comparison of mycangial and 

phoretic fungi of individual mountain pine 

beetles. Canadian Journal of Forest Research. 

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Whitehead, R.J.; Safranyik, L.; Russo, G.; Shore, 

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published by:

USDA Forest Service

Pacific Northwest Region (R6)

Portland, Oregon

FS-R6-RO-FIDL#2/002-2009