USDA United States 

-/- Department 

of Agriculture 

Forest Service 

Rocky Mountain 

Research Station 

Research Note 

RMRS-RN - 13 

September 2002 

Diesel Fuel Oil for Increasing 

Mountain Pine Beetle Mortality 

in Felled Logs 

SmAm Mata 

JmMm Schmid 

DmAm Leatherman 

Mata, S. A.; Schmid, J. M.; Leatherman, D. A. 2002. Diesel fuel 

oil for increasing mountain pine beetle mortality in felled logs. 

Res. Note RMRS-RN-13. Fort Collins, CO: U.S. Department of 

Agriculture, Forest Service, Rocky Mountain Research Station. 

4 P. 

Abstract-Diesel fuel oil was applied to mountain pine beetle 

(Dendroctonw ponderosne Hopkins) infested bolts of ponderosa 

pine (Pinzo ponderosa Lawson) in early June. Just prior to the 

fuel oil application and 6 weeks later, 0.5 ft2 bark samples were 

removed from each bolt and the numbers of live beetles counted. 

Beetle survival was 8.3% in bolts arranged in a single layer and 

4.8% in bolts arranged in 2 layers. 

The Authors 

S.A. Mata is a Forestry Technician, Rocky Mountain Research 

Station. J.M. Schmid is a retired Forest Entomologist. D.A. 

Leatherman is a Forest Entomologist, Colorado State Forest 

Service. 

Disclaimer 

Diesel fuel oil used improperly can be injurious to humans, animals, and 

plants. Follow thc dircctions and heed all precautions for the haudling 

and use of fucl oil. 

Kccp out of the reach of childcrn and animals. Store safely, away from 

food, fecd, and possiblc sourccs of ignition. 

Apply dicscl fuel oil so that it does not cndangcr humans, livcstock, crops, 

bcncficial insccts, fish, and wildlife. Do not apply diesel fi~cl oil in ways 

that may contaminate water; do not clean equipment or dump excess diesel 

fuel oil near ponds, strcarns, or wells. Dispose of empty diesel fuel oil 

containcrs properly. 

Avoid prolonged inhalation of dicscl fucl oil; wear protcctive clothing 

and equipment as specified by thc appropriatc matcrial data safety shcct. 

If your hands bccome contarninatcd with dicsel fuel oil, do not eat or 

drink until you havc washed. In casc diescl fuel oil is swallowcd or gcts in 

the cyes, follow thc first-aid trcatmcnt given on the labcl, and get prompt 

medical attcntion. If diesel fucl oil is spilled on your skin or clothing, 

remove clothing immediately and wash skin thoroughly. 

For additional information, visit thc wcbsite: http://www.arfarfarf.coin/ 

msdsidicsel-no2. html 

Introduction 

Populations of the mountain pine beetle (Dendroctonus 

ponderosae Hopkins) infest and kill ponderosa pine (Pinus 

ponderosa Lawson) trees in the Front Range of Colorado. 

Groups of trees may be killed each year because the mountain pine beetle (MPB) has a I -year life cycle and a new 

generation of beetles emerges annually to attack green trees. 

Tree mortality caused by the MPB becomes a concern for 

forest managers, especially private landowners who wish 

to prevent tree mortality on their property. Initial MPB infestations probably go undetected until the needles on the 

infested trees fade. Once detected, landowners seek ways to 

kill the beetles and prevent the infestation of additional trees. 

Methods of killing MPBs vary with the circumstances of 

the infestation. Sanitation logging of infested trees (McMillin 

and Allen 1999), felling and burning infested trees (Evenden 

et al. 1943, McMillin and Allen 1999), felling infested trees 

and exposing them to solar radiation (Leatherman 2001, 

Negron et al. 2001), felling and peeling off the bark (Evenden 

et al. 1943), and felling and applying lethal chemicals 

(McCambridge 1972, McCambridge et al. 1975) are methods for increasing MPB mortality. Sanitation logging may 

be useful only where the number of infested trees is large 

enough to make logging profitable. Felling and exposing to 

solar radiation may be useful for landowners with a small 

number of infested trees and the equipment to handle the 

trees. Felling and applying lethal chemicals is a simple procedure but the chemicals may be unavailable without a special permit or landowners may refrain from using it because 

the chemical(s) may cause adverse effects on other animal 

species. Further, the availability of chemicals for this purpose has declined substantially in the past decade 

(Leatherman and Cranshaw 1998). For example, Lindane, 

a chemical highly effective against the MPB, has almost 

disappeared because its registration for this particular use 

USDA Forest Service Research Note RMRS-RN-13.2002 
has expired. As the availability of suitable chemicals has 

become limited, the search for substitutes has modestly increased. Many chemicals are restricted in their use and therefore unavailable to landowners. Diesel fuel oil, a commonly 

used fuel in vehicles, is readily available to landowners. 

Because diesel fuel oil reduced spruce beetles (D. rzfipenrzis 

(Kirby)) an average of 90% when applied to spruce logs 

(Schmid 1972b), we tested its effectiveness for causing 

mortality in MPB populations. 

Met hods 

This study was conducted in ponderosa pine stands on 

the Canyon Lakes District of the Arapaho-Roosevelt National Forest in northern Colorado. More specifically, the 

location was about 45 miles northwest of Fort Collins in 

Section 20, R.73 W, T. 9 N, which lies about 3 miles north 

of the resort area known as Rustic in the Poudre Canyon. 

Four MPB-infested trees were felled on June 1 and 2, 

2000. The infested portions of the trees were cut into 4-ft 

bolts; each tree yielded about 5 bolts. The lowermost and 

uppermost portions of the trees were not used because, although 

MPB attacks were present, they lacked MPB brood. Mid-bolt 

diameters ranged from 9.9 to 15.1 inches for the 4 trees. 

Two of the trees were used in one replication of the treatments while the other two trees were used in a second replication of the treatments on an adjacent site. Bolts from each 

pair of trees were sorted into 2 piles but were intermixed 

during sorting so each treatment would have bolts from both 

trees and bolts of various diameters. 

The two treatments consisted of: 1) 5 bolts arranged in a 

single layer that were oriented north-south after fuel oil application, and 2) 5 bolts assanged in 2 layers also oriented 

north-south after application (figure 1). The physical arrangement of the bolts was similar to the design used in the 

solar treatment study by Negron et al. (2001) so that comparisons could be made between the results of the 2 studies. 

Diesel fuel oil was applied to all surfaces of each bolt 

with a sprinkling can on June 1 and 2, 2000 (figure 2). 

Initially, the oil was liberally applied on the upper surface 

so that it was thoroughly soaked and the oil began to run 

down on the lateral surfaces. If the oil began to drip off the 

bark on the lateral surface, application ceased and the bolt 

was rotated slightly so that the oil would not drip on the 

ground. After the oil had soaked into the bark on the upper 

surfaces (figure 3), each bolt was rotated 180 degrees and 

the diesel fuel oil was applied to the opposite side in the 

same manner. Bolts in the 2-layer treatment were treated 

individually and then stacked; the diesel file1 oil was not 

applied to the bolts in the stacked position. 

Prior to the cutting of the trees into bolts, the north sides 

of the trees were marked with paint. After application of the 

fuel oil, the north sides of the bolts were placed so that they 

faced the ground. This orientation was performed because: 

1) previous observations indicated that densities of MPB 

brood are usually greater on the north sides (Schmid 1972a), 

and 2) work in 1999 by Negron et al. (2001) indicated that 

Figure 2. Application of the diesel fuel oil to the bolt with a 

sprinkling can. 

Figure 1. After application of diesel fuel oil, the bolts were Figure 3. End view of a bolt showing the extent of the runoff 

arranged in single and double layers. of the diesel fuel oil on the end. 

USDA Forest Service Research Note RMRS-RN-13.2002 
MPB densities in bolt surfaces directly exposed to the sun 

would suffer substantial mortality. While increasing mortality through solar radiation is desirable, the effectiveness 

of the fuel oil treatment might have been confounded by 

solar-caused mortality. Therefore, the side of the bolt with the 

greatest potential for brood (north side) was positioned downward so mortality would not be influenced by solar radiation. 

Before the diesel fuel oil was applied, one 0.5 ft' bark 

sample was removed from the north surface of each bolt. 

By confining bark sampling to the north surfaces, the effect 

of solar radiation on brood survival is minimized. MPB 

brood (larvae, pupae, and callow adults) and the number of 

attacks were counted and recorded. On July 10- 12, 2000, 

0.5 ft%ark samples were removed from the north surfaces 

of all bolts. MPB brood were counted and recorded. Brood 

in several post-treatment samples were alive but appeared 

discolored and sluggish. Although we suspect that the inactive and discolored brood probably would not have survived, 

they were still counted as live brood. Mean brood densities 

and their standard errors were computed for each treatment 

for each sampling period. MPB brood densities were used 

in analysis of variance testing for significant differences 

between treatments and time of sampling, alpha = 0.05. 

Mean number of attacks per 0.5 ft' of bark were also 

computed for each treatment. The mean number of MPB 

brood and attacks per 0.5 ft' of bark were used to determine 

a population trend ratio (PTR) for the MPB brood (see 

Lessard and Schmid 1990). The PTR is the number of beetles 

expected to emerge (the live brood) divided by the number 

of attacking beetles. The number of attacking beetles is derived by doubling the attack density because it is assumed 

that 2 beetles (a female and a male) are needed in each attack to create the gallery and produce the brood. A PTR 

greater than 1 indicates the MPB population in the bolts 

would be increasing, while a PTR of less than 1 indicates a 

decreasing population. 

Results and Discussion 

Mean densities of MPB brood were significantly different between sampling periods but were not different between 

treatments (table I). Thus, the two-layer treatment was just 

as effective as the one-layer treatment with respect to mortality on the bottom surfaces. Because Negron et al. (2001) 

have shown that survival can be substantial on the upper 

surfaces of bolts in the lower layer in the two-layer solar 

treatment, the one-layer fuel oil treatment is probably preferable in order to gain the benefit of solar radiation on the 

upper surface and thus maximize mortality from the fuel oil 

and solar radiation on the entire circumference. 

Percent survival averaged 8.3% in the single layer treatment and 4.8% in the double layer treatment (table 1). Most 

of the samples had no surviving beetles. Because some "live" 

brood appeared discolored and sluggish, we suspected that 

some of the "live" brood would eventually die and thus result in a lower survival percentage. We also suspect that 

live brood in some samples may have occurred because 

Table 1. Mean (f std. error) numbers of mountain pine beetle brood 

per 0.5 ft2 of bark surface. Means represent combined data for 

the two sets of treatments. 

Treatment Pretreatment Posttreatment Percent survival 

Single Layer 34.8 + 5.9 2.9 f 1.4 8.3% 

Double Layer 41.3 f 5.9 2.0 f 1.4 4.8% 

portions of the bark on these bolts were not soaked as 

throughly as the bark in bolts with no survival. 

Mean attack densities for bolts in the single and double 

layer treatments were 4.1 and 3.5 per 0.5 ft' (table 2). Based 

on these numbers and assuming the mean densities of MPB 

at the last sampling period would emerge to attack live trees 

later in the summer, the PTR was 0.35 for the single layer 

treatment and 0.29 for the 2 layer treatment. Thus, both treatments resulted in a decreasing MPB population. 

In a solar treatment study conducted simultaneously in 

the same area, survival averaged 47.2% in the bottom surfaces of bolts in a single layer (Negron et al. 2001). Survival in the bottom surfaces of bolts in a 2 layer treatment 

averaged 53.9% for bolts in the upper layer and 56% for 

Table 2. Population trend ratios (PTR) for the single layer and double 

layer diesel fuel oil treatments based on attack and brood 

densities per ft2. 

Attack Attacking Emerging 

Treatment densities MPB MPB PTR 

Single Layer 4.1 8.2 2.9 .35 

Double Layer 3.5 7.0 2.0 .29 

bolts in the lower layer (Negron et al. 2001). Thus, the diesel fuel oil treatments were much more effective than solar 

radiation treatments in reducing beetle survival on the bottom surfaces of the bolts. 

Because the number of sample trees (4) sprayed with 

diesel oil is low, the reader might question whether the diesel oil would be effective under different brood densities. 

Our pretreatment brood densities were comparable to the 

1999 and 2000 pretreatment brood densities of Negron et 

al. (2001) wherein about 50 trees were felled and sampled. 

Although our sample is small, it appears to be representative of existing conditions at the time so that the fuel oil 

would be effective against the brood densities we observed 

as well as those observed by Negron et al. (2001). 

Application Procedure 

Fuel oil can be easily applied with a sprinkling can. Liberally apply the fuel oil to the upper surface of a bolt so that 

it flows onto the lateral surfaces without dripping onto the 

ground or splashing on adjacent vegetation. Allow the f~~el 

oil to soak in before rotating the bolt and applying more 

fuel oil. Repeat the sequence until the bark surface area has 

been well soaked. After all bolts have been treated, 

USDA Forest Service Research Note RMRS-RN-13. 2002 3 
thoroughly clean the sprinkling can before it is to be used 

for other purposes like watering flowers or garden vegetables. 

Application Costs 

Approximately 5 gallons of diesel fuel oil were used to 

treat the 10 bolts for each replication of the 2 treatments. 

Diesel fuel oil at a local gas station at the time of this study 

cost about $1.20 per gallon. Based on this price, treatment 

of the MPB-infested portion would cost about $3 per tree. 

Additional costs would be incurred for felling and cutting 

the tree into treatable-length bolts. 

Environmental Concerns 

If forest managers use diesel fuel oil when treating MPBinfested bolts, they should observe all precautions because 

the treatment can be injurious to humans, animals, and plants. 

However, judicious application of the diesel fuel oil can 

essentially eliminate the detrimental effects of the treatment 

to everything outside the MPB-infested bolt. 

Fuel oil is a flammable substance that burns readily. While 

fuel oil-soaked bolts will burn more readily than dry bolts, 

we do not believe that they will spontaneously combust and 

start a fire. 

Benefits for the Private Forest Managers 

Private landowners should consider using diesel fuel oil 

for treatment of MPB-infested trees because: 

1. Diesel fuel oil will effectively lower MPB brood survival. 

2. Diesel fuel oil is effective on all surfaces of the bolts and the 

bolts do not have to be rotated or handled after application. 

3. Diesel fuel oil is relatively cheap and may be more cost 

effective than solar radiation because the bolts have to 

be handled only once. 

4. Diesel fuel oil can be just as effective as some insecticides but does not require the special applicator's licenses 

or permits needed for purchase and application of some 

insecticides. 

References 

Evenden, J.C.; Bedard, W.D.; Struble, G.R. 1943. The mountain 

pine beetle, an important enemy of western pines. U.S. 

Department of Agriculture Circular No. 664. 25 p. 

Leatherman, D.A. 2001. Solar treatment of mountain pine beetle 

trees. Colorado State Forest Service Insect Information Series 

MPB: No. 1. 2p. 

Leatherman, D.A. and W.S. Cranshaw. 1998. Mountain pine beetle. 

Colorado State University Cooperative Extension Bulletin, 

Insect Series. No. 5.528. 4 p. 

Lessard, E.D., and J.M. Schmid. 1990. Emergence, attack densities, 

and host relationships for the Douglas-fir beetle (Dend~octonus 

pseudotsugae Hopkins) in northern Colorado. Great Basin 

Naturalist 50: 333-338. 

McCambridge, W.F. 1972. Treatment height for mountain pine 

beetles in Front Range ponderosa pine. Res. Note RM-218. 

Fort Collins, CO: U.S. Department ofAgriculture, Forest Service, 

Rocky Mountain Forest & Range Experiment Station. 2 p. 

McCambridge, W.F.; Laut, J; Gosnell, R. 1975. Fumigate firewood 

infested with mountain pine beetle. Res. Note RM-289. U.S. 

Department of Agriculture, Forest Service, Rocky Mountain 

Forest & Range Experiment Station. 2 p. 

McMillin, J.D. and K.K. Allen. 1999. Evaluation of mountain pine 

beetle activity in the Black Hills National Forest. Biological 

Evaluation R2-00-03. Golden, CO: U.S. Department of 

Agriculture, Forest Service, Rocky Mountain Region, Forest 

Health Management. 18 p. 

Negron, J.; Shepperd, W.D.; Mata, S.A.; Popp, J.B.; Asherin, L.A.; 

Schoettle, A.W.; Schmid, J.M.; Leatherman, D.A. 2001. Solar 

treatment for reducing survival of mountain pine beetle in 

infested ponderosa and lodgepole pine logs. RMRS-RP-30. Fort 

Collins, CO: U.S. Department of Agriculture, Forest Service, 

Rocky Mountain Research Station. 11 p. 

Schmid, J.M. 1972a. Emergence, attack densities, and seasonal 

trends of mountain pine beetle (De~zdroctonus porzderosae) in 

the Black Hills. Res. Note RM-211. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain 

Forest & Range Experiinent Station. 7 p. 

Schmid, J.M. 1972b. Reduced ethylene dibromide concentrations 

or fuel oil alone kills spruce beetles. Journal of Economic 

Entomology 65: 1520-1 521. 

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USDA Forest Service Research Note RMRS-RN-13.2002 

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