Optimum dosage of verbenone to reduce infestation of mountain pine beetle in lodgepole pine stands of central Idaho

10 Pages·1991·0.53 MB·English

by  Amman, Gene D

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Optimum Dosage
of
Verbenone Reduce
to
Infestation of Mountain Pine
Beetle Lodgepole Pine
in
Stands of Central Idaho
Gene Amman
D.
Ralph W. Thier
Julie C. Weatherby
Lynn A. Rasmussen
A. Steve Munson
THE AUTHORS prevention of infestation by mountain pine beetle
GENE D. AMMAN is principal entomologist and [anDneonudnrtoocftot>neuestlpeoinnfdeesrtaotsiaoneoHcocpukr.)r.edIwnh1e9r8e8,vetrhte)elneoasnte
Project Leader, Mountain Pine Beetle Population bubble capsules (released atthe rate of 5 mg per
Dynamics research work unit, Intermountain Research capsule per24 hours at 25 °C)were deployed in agrid
Station, Ogden, UT. pattern at a rate of 49 per hectare. The towest per-
RALPH W. THIER is entomologist, Forest Pest centage oftrees infested was 0.21 percent In the
Management, Intermountain Region, Forest Service, 49 capsules per hectare treatment, compared to 5.39
Boise, ID. percent in check stands. In 1989, the least infestation
JMUaLnIaEgeCm.eWntE,AITnHteErRmoBunYtaisinenRteogmioolno,giBsoti,seF,orIeDs.t Pest wtraesesowbteariene0d.7w2itpher1c0e0ntc,acposumlpeasrepedrtohe4c.t9a3rep.erIcnefnetstiend
check stands. Beetle infestation did not increase in
LYNN A. RASMUSSEN is biologicaltechnician. the immediate area surrounding treatment plots.
Mountain Pine Beetle Population Dynamics research
work unit, Intermountain Research Station, Ogden, UT. ACKNOWLEDGMENTS
AM.anSaTgEeVmeEnMt,UNInStOerNmoiusnetnationmoRleoggiiosnt,.OFgodreenst,PUeTs.t We thank the following persons inthe Forest Ser-
vice, Forest Pest Management, and Intermountain
RESEARCH SUMMARY Research Station for help in establishing plots, distrib-
uting verbenone, and making stand measurements:
Phil Mocettini, Dick Halsey, Bryan Gardner, Pat
Five dosages of verbenone, a bark beetle anti-
aggregative pheromone, were deployed in lodgepole Pinkerton, Boise, ID; Dave Holland, Valerie Kalve,
Sheri Smith, and Jim Vandygriff. Ogden, UT.
pine {Pinus contorta Dougi. var. latifolia Engelm.)
stands in Idaho to determine optimum level for
The use oftrade orfirm names in tfiispublication is forreaderinformation anddoes not
implyendorsementbythe U.S. DepartmentofAgriculture ofanyproductorsen/ice.
Intermountain Research Station
32425th Street
Ogden. UT84401
Optimum Dosage Verbenone
of to
Reduce
Infestation of l\/lountain
Pine Beetle in Lodgepole Pine
Stands of Central Idaho
Gene D. Amman
Ralph W. Thier
Julie C. Weatherby
Lynn A. Rasmussen
A. Steve Munson
INTRODUCTION needed to reduce MPB infestations? (2) Would MPB
be attracted or dispersed into areas adjacent to
Verbenone (4,6,6-trimethylbicyclo[3.1.1]-hept-3- verbenone-treated stands, resultingin increased
en-2-one) is considered the principal antiaggregative numbers ofinfested trees in adjacent stands?
pheromone component ofthe mountain pine beetle
(MPB), Dendroctonusponderosae Hopkins, and METHODS
apparently serves to space attackingbeetles, thus
preventingovercrowdingoflarvae. The presence of A study area was selected in the Sawtooth Valley
verbenone in the MPB pheromone complex was first ofthe Sawtooth National Recreation Area, ID, atan
reportedby Pitman and others (1969). average elevation of2,256 m above sea level. Lodge-
Verbenone is derived from three sources: female pole pines of15.2 cm and larger diameter atbreast
beetles, autoxidation ofalpha-pinene, and microor- height (d.b.h.) averaged 20 cm d.b.h. and 144 years
ganisms (primarilyyeasts) growingin established old. Species composition within the stands aver-
galleries (Hunt and Borden 1989). Field tests of aged 75 percent lodgepole pine, with the remainder
MPB
response in British Columbia, Canada, re- beingmostly Douglas-fir {Pseudotsuga menziesii
vealed thatverbenone, when released in funnel var.glauca [Beissn.] Franco) and a few quaking
traps at 1 or 5 mgper 24 hours in the presence of aspen {Populus tremuloides Michx.).
MPB
the attractive synthetic lure (frans-Verbenol, Verbenone capsules consisted ofa clear plastic
exo-Brevicomin, and myrcene), reduced the response bubble and a clear membrane, with a cardboard
ofmales by approximately 75 percent. Female cover to shade the capsule. Each capsule contained
response was similar, although the reduction was 0.5 gofverbenone, which wasreleased atthe rate of
not statistically significant (Borden and others 1987). 5 mgper capsule per 24 hours at 25 °C. The cap-
In Utah, the addition ofverbenone (released atthe sules were stapled to the north sides oftrees, 2 m
rate of5 mgper 24 hours at 25 °C) to funnel traps above ground. Verbenone had a chemical purity of
MPB
baited with lure resulted in a 97 percent 98.6 percentand an optical purity of(-)-72 percent.
reduction in catch ofMPB, compared with catch in In 1988, a complete block design, replicated seven
MPB
traps baited with lure alone (Schmitz 1989; times, was used to testfive densities ofverbenone
Schmitz and McGregor 1990). capsules (0, 25, 49, 100, and 169 perhectare, spaced
Synthetic verbenone deployed in clear plastic in a grid pattern within the treated plots. Plots
bubble capsules (obtained from Phero Tech Inc., were 1 ha in size and were located 100 m apart.
Delta, BC, Canada) at 100 capsules perhectare Treatments within the first replicate were ran-
was tested in both the Western United States and domly assigned. This order was followed through-
western Canada to reduce MPB infestation (Amman out the remaining replicates to avoid placingthe
and others 1989; Lindgren and others 1989). Both same treatment in adjacent plots in areas where
tests demonstrated that verbenone reduced MPB more than one replicate was established. Three
infestations in stands baited or unbaited with the replicates were established atAlturas Lake Creek,
MPB lure. Two questions arose from these tests: two atVat Creek, and one each at Beaver Creek
(1) What is the optimum dosage ofverbenone and Pole Creek,
1
In 1989, the dosage-response portion ofthe study analysis ofvariance (ANOVA) procedure (SAS
(objective 1) was repeated, with the following 1987). We did not use a multiple-comparisons
changes: procedure, which wouldhave been inappropriate
(Warren 1986). The item ofinterest is howbeetle
1. Treatments were replicated eighttimesinstead response changes as a fimction ofverbenone level.
ofseven.
2. Anewly designed capsule was used, consisting bDeieftfleereinncfeesstiantinounmabmeorsngoftgrreeaetnmetnrtesesweavraeilaalbsloe for
ofan opaque bubble with clear plastic membrane. tested byANOVA.
Each capsule contained 0.8 g ofverbenone. To assess whether MPB infestations increased in
3. Treatments were randomized within each
stands immediately adjacentto the 1988 verbenone
block, instead offollowingthe same order in all
plots, two 20-m-wide strips were established around
replicates.
4. The Vat Creek area was discontinued from each plot (fig. 1), and all trees infested in 1987 and
1988 were counted and tallied separatelyfor each
tshtruedeynbeecwauasreeaosfwleorweleavdedleodf—beAelttlueriansfeLsatkaet,ioSn,taatned strip. Numbers of1987-infested trees show MPB
— infestation prior to verbenone treatment and ratio
land, and West Beaver Creek each containingone
ofchange followingtreatment. Numbers of1988-
replicate.
infested treesin each strip were analyzed separately
Treatments were applied June 20 and 21, 1988, byANOVA Numbers, ratherthan percentages of
andJune 19 to 21, 1989. Treatment effects were infested trees, were used in order to save inventory-
assessed August 16 to 18, 1988, and August21 to ing all survivingtrees in the strips forpercentage
23, 1989, after all beetleshad flown, as determined calculations.
by beetles emerginginto cages stapled on infested
trees. A 100 percent survey ofeach plot was made
to measure the d.b.h. ofall lodgepole pine 12.7 cm RESULTS AND DISCUSSION
and larger, and to determine tree mortalityby MPB
Treatment Plots
for 1987, 1988, and 1989. Treatment effects within
plots were evaluated by the percentage oflodgepole The percentages ofnewly infested trees in plots
pine 12.7 cm and lMarPgBer d.b.h. in each plot that was treated with verbenone capsules in 1988 were all
mass-attacked by followingverbenone treat-
significantly lower (means are 25 = 1.80 percent;
ment. The arcsin transformation was usedforper- 49 = 0.21 percent; 100 = 0.51 percent; 169 = 1.71
centages ofinfested trees that were analyzedby
percent) than the check stand (P < 0.003;x = 5.39
percent) (tables 1 and 2). In 1989, the percentages
ofnewly infested trees were also significantly
different amongtreatments (P < 0.012) and among
blocks (P < 0.001) (table 3). Differences among
blocks do not invalidate the testbut do indicate that
the precision ofthe experiment was increased by
use ofthe randomized block design, where each
100 m--
treatment appears in each block (Steel and Torrie
1960). The least amount ofinfestation occurred in
the 100 capsules perhectare treatment(x = 0.72
20 m
percent) compared to the check (x = 4.93 percent)
(table 4). In both years, the trend is for reduced
20 m infestation with increased verbenone up to 49
1 - HECTARE PLOT capsules perhectare in 1988 and 100 capsules
in 1989. Larger numbers ofverbenone capsules
resulted in increased infestation (fig. 2). Borden
and Lindgren (1988) also noted more trees were
attacked when high dosages ofverbenone were
used.
Amman and others (1989) and Lindgren and
others (1989) showed that 100 capsules perhectare
MPB
reduced infestation in stands oflodgepole
pine, either in the presence or absence ofthe
aggregative MPB lure. Our studies confirm these
Figure 1—Design of verbenonetreatment plot findings. Although 49 capsules per hectare
and surrounding strips used in the 1988tests.
2
—
Table 1 Mountain pine beetle infested and uninfested lodgepole pines per hectare in verbenone-treated plots and in
surrounding strips, Sawtooth National Recreation Area, ID, 1988
Treated plot First 20-m-wide strip Second 20-m-wlde strip
Green trees^ Rriaattiiov owif Ratio of
Treatment available Trees Trees Infested InfoQtoff Trees Infested licolcu
II
Wo
(No. of forattack iIIn1fVews&tvaUd Trees Infested II IIVv9
capsules) 1988 iIInI 11987f In 1988 1987 1988 1Qftft/1Qft7 1987 1988 11Q9a0f0tr/11a90afj
X X X Percent^ X X X X
Check 528 14.9 27.0 5.39 5.7 22.1 3.9 5.1 18.5 3.6
25 582 6.0 10.3 1.80 7.7 16.5 2.1 7.1 19.4 2.7
49 534 6.1 1.1 .21 6.6 12.6 1.9 5.7 18.6 3.3
100 587 14.4 3.0 .51 6.6 14.0 2.1 2.9 12.7 4.4
169 527 9.9 8.9 1.71 8.5 8.2 1.0 5.7 6.6 1.2
'Trees 12.7cmandlargerd.b.h. availablefort>eetiestoinfestin 1988.
^Percentageoftrees 12.7cmandlargerd.b.h. infestedbymountainpinebeetles.
— —
Table 2 Randomized block ANOVAstatisticsfor.percent- Table 3 Randomized blockANOVAstatisticsforpercent-
ages (arcSin transformation) of lodgepole pine ages (arcsin transformation) of lodgepole pine
infested by mountain pine beetle in plots treated infested by mountain pine beetle in plotstreated
with different dosagesof verbenone. Sawtooth with different dosages ofverbenone. Sawtooth
National Recreation Area, ID, 1988 National Recreation Area, ID, 1989
Mean sum Mean sum
Source df ofsquares Fratio P Source df ofsquares Fratio P
Block 6 1.149 1.23 0.324 Block 7 2.093 4.71 0.001
Treatment 4 5.207 5.59 .003 Treatment 4 1.748 3.93 .012
Error 24 .931 Error 28 .445
—
Table4 Mountain pine beetle infested and uninfested lodgepole pines per hectare
in verbenone-treated plots, Sawtooth National Recreation Area, ID. 1989
Treatment Green trees^ Trees
(No. of) available for infested
capsules) attack, 1989 In 1988 Trees Infested In 1989
X X X Percent^
Check 614 12.0 30.3 4.93
25 559 11.1 21.8 3.89
49 650 9.9 16.4 2.52
100 606 7.6 4.4 .72
169 507 6.8 8.0 1.58
'Trees 12.7cmandlargerd.b.h.availableforbeetlestoinfestin 1989.
^Percentageoftrees 12.7cmandlargerd.b.h. infestedby mountain pinebeetles.
3
CHECK 25 49 100 169
VERBENONE CAPSULES/HA
—
Figure 2 Percentage of lodgepole pinetrees 12.7cm and largerd.b.h. infested t)y
MPB in plotstreated with different numbersofverbenone bubble capsules in 1988
and 1989, Sawtooth National Recreation Area, ID.
appeared to do equally well in 1988, MPB infesta- (table 1). Bentz and others (1989) did notfind a
tion was unacceptably high in 1989, compared to significant effect due to number of uninfes-
that achieved with 100 capsulesperhectare (fig. 2). tedtreesordiameterclassintests ofverbenone
in ponderosa pine stands.
Verbenone Effect Outside
Treated Plots
No significant difference occurred in the number
MPB
oftrees perhectare killed by within the two
20-m-wide strips around verbenone-treated plots
(P > 0.58 and 0.32). Although none ofthe capsule
treatments differed significantly (table 1), thetrend
isforfewerbeetle-infested trees in strips surround-
ingplots treated with verbenone than in check plots
(fig. 3). These data show that MPB infestation is
not increasedaroundverbenone-treatedplots,but
rather that the verbenone effect may extendbeyond
boundaries ofthe treated plots, especially ata
dosage of169 capsules perhectare. We speculate
thatmost ofthebeetlesdispersedfi*omtreatedplots
flewbeyond the two 20-m-wide strips surrounding
the plotsbefore infestingtrees.
Tree Numbers
PLOT FIRST SECOND
Stand characteristics are important to MPB STRIP STRIP
infestation behavior (Cole and Amman 1980). In AREA
the 1988 and 1989 tests, no significant differences
occurred in eitherthe numbers ofinfested trees Figure3—Ratioof 1988to 1987 infested
from which beetles would have emerged to infest lodgepolepine in plotstreated with different
trees duringthe testorin numbersoflodgepole pine numbisrsofverbenone capsules and intwo
available for infestation amongthe treated stands surrounding 20-m-wide strips.
4
CONCLUSIONS Cole, W. E.; Amman, G. D. 1980. Mountain pine
These results demonstrate that MPB infestations bCeoeutrlseedoyfnaanmiicnsfeisntaltoidogne.pGoelne.piTneechf.orReestps..IPNaTr-t89I..
at densities ofsix to 14 infested lodgepole pine per Ogden, UT: U.S. Department ofAgriculture,
hectare are most effectively reducedby verbenone Forest Service, Intermountain Forest and Range
treatment at a dosage rate of100verbenone cap- Experiment Station. 56 p.
sules perhectare (release rate of5 mgper capsule Hunt, D. W. A.; Borden, J. H. 1989. Terpene alcohol
MPB
per 24 hours at 25 °C). infestation does not pheromone production byDendroctonuspon-
increase in 40-m-wide strips immediately surround- derosae and Ipsparaconfusus (Coleoptera:
ingverbenone-treated plots oflodgepole pine 1 hec- Scolytidae) in the absence ofreadily culturable
tare in size. Verbenone couldbe used operationally microorganisms. Journal ofChemical Ecology.
to preventinfestation, ifthe risk oflosingsome 15: 1433-1463.
trees is acceptable. Lindgren, B. S.; Borden, J. H.; Cushon, G. H.;
Chong, L. J.; Higgins, C. J. 1989. Reduction of
REFERENCES
mountain pine beetle (Coleoptera: Scolytidae)
attacks by verbenone in lodgepole pine stands in
Amman, G. D.;Thier, R. W.; McGregor, M. D.; British Columbia. Canadian Journal ofForest
Schmitz, R. F. 1989. Efficacy ofverbenone in Research. 19: 65-68.
reducinglodgepole pine infestation by mountain Pitman, G. B.;Vit6, J. P.; Kinzer, G. W.; Fentiman,
pine beetles in Idaho. Canadian Journal ofForest
A. F., Jr. 1969. Specificity ofpopulation-
Research. 19: 60-64. aggregating pheromone in Dendroctonus. Journal
Bentz, B.; Lister, C. K; Schmid, J. M.; Mata, S. A.; ofInsect Physiology. 15: 363-366.
Rasmussen, L. A.; Haneman, D. 1989. Does SAS Institute. 1987. SAS/STAT guide for personal
verbenone reduce mountain pine beetle attacks computers. Cary, NC: SAS Institute. 1028 p.
in susceptible stands ofponderosa pine? Res. Note Schmitz, R. F. 1989. Efficacy ofverbenone for
RM-495. Fort Collins, CO: U.S. Department of preventinginfestation ofhigh-value lodgepole
Agriculture, ForestService, Rocky Mountain pine stands by the mountain pine beetle. In:
Forest and Range Experiment Station. 4 p. Amman, G. D., compiler. Proceedings—sympo-
Borden, J. H.; Lindgren, B. S. 1988. The role of sium on the management oflodgepole pine to
semiochemicals in IPM ofthe mountain pine minimize losses to the mountain pine beetle; 1988
beetle. In: Payne, T. L.; Saarenmaa, H , eds. July 12-14; Kalispell, MT. Gen. Tech. Rep. INT-
Integrated control ofscolytid barkbeetles: 262. Ogden, UT: U.S. Department ofAgriculture,
Proceedings ofthe lUFRO Working Party £ind Forest Service, Intermountain Research Station:
XVII International Congress ofEntomology
75-80.
Symposium; 1988 July 4; Vancouver, BC. Schmitz, R. F.; McGregor, M. D. 1990. Anti-
[Blacksburg, VA: Virginia Polytechnic Institute aggregative effect ofverbenone on response
and State University, Department ofEntomology]: ofthe mountain pine beetle to baited traps. Res.
247-255.
Pap. INT-423. Ogden, UT: U.S. Department of
Borden, J. H.; Ryker, L. C; Chong, L. J.; Pierce, Agriculture, ForestService, Intermountain
H. D., Jr.;Johnston, B. D.; Oehlschlager, A. C. Research Station. 7 p.
1987. Response ofthe mountain pine beetle, Steel, R. G. D.;Torrie, J. H. 1960. Principles and
Dendroctonusponderosae Hopkins (Coleoptera: procedures ofstatistics. New York: McGraw-Hill.
Scolytidae), tofive semiochemicals in British 481
p.
Columbia lodgepole pine forests. Canadian Warren, W. G. 1986. On the presentation of
Journal ofForest Research. 17: 118-128. statistical analysis: reason or ritual. Canadian
Journal ofForest Research. 16: 1185-1191.
5
Amman, Gene D.; Thier, Ralph W.; Weatherby, Julie C; Rasmussen, Lynn A.; Munson,
A. Steve. 1991. Optimum dosageofverbenoneto reduce infestation of mountain pine
beetle in lodgepole pine stands ofcentral Idaho. Res. Pap. INT-446. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Intermountain Research Station. 5 p.
Fivedosagesof verbenone weredepbyed in bdgepole pine stands in 1988 and 1989to
determineoptimum levelforprevention of infestation by mountain pine beetle. In 1988, the
least amountof beetle infestation occurred where 49 bubble capsules per hectare were
deployed in agrid pattern. Each capsule released at a rateof 5 mg percapsule per24
hours at 25 "C. The percentageoftrees infested was 0.21 percent (49 capsules per hec-
tare) compared to5.39 percent in checkstands. In 1989, least infestation wasobtained
with 100capsules per hectare. Infestedtreeswere 0.72 percent, compared to4.93 per-
cent in check stands. Beetle infestationdid not increase in areasadjacenttoverbenone-
treated blocks.
KEYWORDS: Dendroctonusponderosae, Pinuscontorta, pheromone
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