Geographic variation in susceptibility of the spruce budworm,Choristoneura fumiferana(Lepidoptera: Tortricidae), toBacillus thuringiensisssp. kurstaki is limited

1996 ◽  
Vol 74 (10) ◽  
pp. 1943-1946
Author(s):  
Kees van Frankenhuyzen ◽  
Debbie Gauthier ◽  
John Dedes
Keyword(s):  
Geographic Variation ◽  
Prince Edward Island ◽  
Choristoneura Fumiferana ◽  
Internal Standard ◽  
Spruce Budworm ◽  
Instar Larva ◽  
Probit Regression ◽  
Forest Protection ◽  
Susceptible Population ◽  
Laboratory Colony

Geographic variation in susceptibility to the pathogen Bacillus thuringiensis Berliner ssp. kurstaki was assessed among five populations of the spruce budworm, Choristoneura fumiferana (Clemens), across Canada. Larvae or pupae were collected from Prince Edward Island, northern New Brunswick, central Ontario, northeastern Alberta, and northeastern British Columbia. The response of field populations to the 1980 industrial standard of the HD-1 strain of the pathogen was compared with the concurrent response of a laboratory colony as an internal standard. Equal slopes of the probit regression lines indicated homogeneity of variation in susceptibility among populations. LC50values ranged from 2.6 international units (IU) per sixth-instar larva for the most susceptible population to 8.3 IU per larva for the least susceptible. Although significant, the variation in population susceptibility was within the range of variation that is commonly observed among repeated bioassays against cohorts of a single population. We conclude that variation in susceptibility to B. thuringiensis among spruce budworm populations is low. The data provide a basis for monitoring changes in susceptibility of spruce budworm populations in response to increased use of this pathogen in forest-protection programs.

Evidence of DDT Resistance in Populations of Spruce Budworm, Choristoneura fumiferana (Clem.), From DDT-sprayed Areas of New Brunswick

1965 ◽  
Vol 97 (12) ◽  
pp. 1281-1293 ◽  
Author(s):  
A. P. Randall
Keyword(s):  
New Brunswick ◽  
Large Scale ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Data Interpretation ◽  
Fuel Oil ◽  
Susceptible Population ◽  
Mortality Curve ◽  
Progressive Development ◽  
Ddt Resistance

AbstractA series of laboratory toxicological experiments using various concentrations of oil formulated DDT solutions (AR-50/fuel oil (2:7 V/V)) was carried out on 5th and 6th instar spruce budworm larvae collected in the field from DDT-sprayed and untreated areas of New Brunswick, Canada, and Maine, U.S.A.Results obtained in 1959, 1961, and 1962 with larvae collected from isolated, unsprayed areas in New Brunswick showed a consistent, straight log-dosage probit mortality curve. Larvae collected in 1962 and 1963 from infestation centres previously subjected to three, four, and five applications of non-consecutive large-scale aerial sprays of DDT showed a significant departure from the straight log-dosage probit curve previously obtained. The departure occurs as a change in the shape of the curve as well as a shift to the higher concentration range of DDT. The magnitude of change appears to be correlated with the number of sprays to which the population was exposed. Results obtained in 1962 and 1963, from untreated control and inter-spray areas, bounded by DDT-sprayed forest lands, showed a small but significant departure from the normal straight probit line of a susceptible population. These changes are indicative of a progressive development of DDT resistance in wild populations of spruce budworm.Studies on the effect of the tolerance of spruce budworm larvae within instar classes to the action of DDT showed that the early phase of instar development immediately after moulting is more susceptible to the action of DDT, whereas the latter phase of instar development immediately prior to moulting is more tolerant to topical application of DDT than the average for the instar. This effect is evident in both susceptible and resistant populations.The data interpretation assumes that a deviation from the straight line probit dosage – mortality curve is indicative of a difference in the DDT-susceptibility factor of the budworm population and that in the course of the tests, the amount of toxicant causing mortality was not proportional to the dosage.

A SIMPLE TECHNIQUE FOR INDEXING THE MATING STATUS OF MALE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1986 ◽  
Vol 118 (1) ◽  
pp. 37-41 ◽  
Author(s):  
J.C. Bergh ◽  
W.D. Seabrook
Keyword(s):  
Simple Technique ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Reliable Index ◽  
Mating Status ◽  
Yellow Substance ◽  
Laboratory Colony ◽  
Unmated Male

AbstractSection 7 of the primary simplex of the ductus ejaculatorius of unmated male spruce bud worm moths, Choristoneura fumiferana, contains a yellow substance that is not present in recently mated males. The yellow substance occurs in laboratory-colony males reared on diet and in feral males reared on foliage. It is shown that the presence/absence of this material is a reliable index of copulation during the previous 24 h. Although the yellow substance regenerates over a period of several days, males 0–72 h post-copulation may be indexed when compared with unmated males of similar age.

The susceptibility of the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae), to Heterorhabditis heliothidis (Nematoda: Heterorhabditidae) in the laboratory

1982 ◽  
Vol 60 (5) ◽  
pp. 958-961 ◽  
Author(s):  
Jean R. Finney ◽  
K. P. Lim ◽  
Gordon F. Bennett
Keyword(s):  
Biological Control ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Instar Larva ◽  
Balsam Fir ◽  
Blue Spruce ◽  
Higher Temperature

Exposure of 4th, 5th, and 6th instar Choristoneura fumiferana to Heterorhabditis heliothidis (120 nemas per larva) resulted in 100% mortality within 48 h at 24 ± 1 °C. At 17 °C, 100% mortality was achieved within 120 h. Reduction of the dose to 15 nemas per 5th–6th instar larva caused 70% mortality at 24 ± 1 °C and 15% mortality at 17 °C within 120 h. At the higher temperature, mortalities of 80 and 73% were recorded for pupae exposed to 150 and 60 nemas per pupa, respectively. When 6th instar larvae on foliage of balsam fir or blue spruce were treated with the nematode suspension (120 nemas per larva) 100% mortality was obtained within 72 h at 24 ± 1 °C. The potential of using this nematode in biological control of spruce budworm is discussed.

Re-examining wood supply in light of future spruce budworm outbreaks: A case study in New Brunswick

2013 ◽  
Vol 89 (01) ◽  
pp. 42-53 ◽  
Author(s):  
C.R. Hennigar ◽  
T.A. Erdle ◽  
J.J. Gullison ◽  
D.A. MacLean
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Forest Protection ◽  
Wood Supply ◽  
Long Run ◽  
Biological Insecticide ◽  
Salvage Harvesting

Forest protection (spraying of biological insecticide), salvage harvesting, and strategic re-planning are typical mitigation options to reduce wood supply impacts caused by spruce budworm (Choristoneura fumiferana [Clem.]) defoliation. However, all such measures are expensive and difficult to implement, and decisions about if and to what extent such measures should be applied hinge on the magnitude of benefits and associated costs. We used an integrated forest estate pest-impact planning model to quantify harvest impacts for three plausible outbreak scenarios, and the effect of these typical mitigation strategies for 3.0 million ha in New Brunswick. Cumulative harvest reductions, relative to the no defoliation case, reached 18% and 25% by 2052 under moderate and severe defoliation patterns, respectively. We demonstrate that up to 30% to 50% of these projected reductions could be avoided through foliage protection treatments, depending on the outbreak scenario. Salvage and re-planning mitigated harvest losses by up to 20% in the short term (20 to 25 years), but had little benefit over the long run (40+ years). Even with aggressive implementation of all mitigation measures, significant harvest impacts (10% reduction from 2017 to 2042) were unavoidable, regardless of outbreak scenario.

scholarly journals Efficacy of Insecticide Aerial Spraying Programs to Reduce Tree Mortality During a Spruce Budworm Outbreak (1967‒1992) in the Quebec Province.

2021 ◽  
Author(s):  
Alvaro Fuentealba ◽  
Alain Dupont ◽  
Roberto Quezada-Garcia ◽  
Éric Bauce
Keyword(s):  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Stand Age ◽  
Similar Reduction ◽  
Forest Protection ◽  
Protection Goal ◽  
Aerial Spraying ◽  
Stand Characteristics

Abstract Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in Eastern North America. The main approach to protect Quebec forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial spraying of insecticides in the global forest protection strategy, little is known about its real impact on tree mortality reduction or the stand characteristics that may affect its long-term efficacy. We evaluate the efficacy of the protection program implemented between 1967 and 1992 in reducing tree mortality during the previous outbreak in Quebec and how its efficacy is affected by stand characteristics such as drainage quality and stand age. We established 422 plots in Eastern Quebec based on the following parameters: insecticide application (0-13 years), stand composition, drainage quality, and stand age at the beginning of the previous outbreak. Our results show that unprotected plots exhibited in average between 18 and 32.6% higher mortality than protected plots. Insecticide efficacy was affected by drainage quality. For example, protected plots established on sites with bad drainage quality exhibited 49% less balsam fir mortality than unprotected plots. Furthermore, immature and mature protected stands exhibited a similar reduction in balsam fir mortality (32.2 and 32.1% less mortality respectively) compare to unprotected stands. Our results may be useful for decision-makers not only to decide where and when apply insecticides during a spruce budworm outbreak but also, they may help to determine the pertinence of continuous protection during longer than usual outbreaks depending on protection goal.

Potential wood supply losses to spruce budworm in New Brunswick estimated using the Spruce Budworm Decision Support System

2002 ◽  
Vol 78 (5) ◽  
pp. 739-750 ◽  
Author(s):  
D A MacLean ◽  
K P Beaton ◽  
K B Porter ◽  
W E MacKinnon ◽  
M G Budd
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
New Brunswick ◽  
Support System ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Timber Harvesting ◽  
Management Plan ◽  
Forest Protection

The Spruce Budworm Decision Support System (SBW DSS) was used to estimate potential volume losses to a future spruce budworm (Choristoneura fumiferana (Clem.)) outbreak in New Brunswick. The SBW DSS was implemented separately on each of the ten Crown Timber Licenses, using data from forest industry management plan timber yields and harvest schedules; values were then compiled for all of New Brunswick. Potential volume losses on privately owned forest (industrial freehold and private woodlots) were estimated by matching stand types with those for Crown land. Total potential volume losses of 83 million and 195 million m3 of spruce–fir (Picea spp. – Abies balsamea (L.) Mill.) were predicted for "normal" and "severe" budworm outbreak scenarios, defined based on past outbreaks in New Brunswick and Nova Scotia and assumed to start in 2000. Simulated timber supply losses were 42 million, 40 mil-lion, and 1 million m3 on Crown, freehold, and federal land, respectively, under a normal outbreak scenario, versus 99 million, 92 million, and 3 million m3 under a severe outbreak scenario. On Crown land, 33% of the predicted loss in a severe outbreak occurred in stands scheduled for harvest over the next 30 years, 26% occurred in stands not scheduled for harvest for at least 30 years, and 41% was in the non-timber harvesting landbase (11% in Old Softwood Forest Habitat, 12% in Deer Wintering Areas, 14% in riparian buffers, and 3% in inaccessible areas). Harvest levels 11–20 years in the future were very sensitive to reduction in yields caused by defoliation. Under a severe outbreak scenario, if 40% of the landbase was not protected for 2, 5, or 8 years to limit defoliation (simulating spraying the insecticide Bacillus thuringiensis, B.t.), 2007–2011 harvest level reductions of 4.0, 6.0, and 8.4 million m3 , respectively, would be necessary. We conclude that the only way that planned harvest levels for New Brunswick can be maintained, under a future spruce budworm outbreak, is with effective targeted use of insecticides for forest protection. Key words: defoliation, growth reduction, mortality, protection planning

scholarly journals Influence of a Foliar Endophyte and Budburst Phenology on Survival of Wild and Laboratory-Reared Eastern Spruce Budworm, Choristoneura fumiferana on White Spruce (Picea glauca)

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 503 ◽  
Author(s):  
Dan Quiring ◽  
Greg Adams ◽  
Leah Flaherty ◽  
Andrew McCartney ◽  
J. David Miller ◽  
...  
Keyword(s):  
Field Study ◽  
Wild Population ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Intervention Strategy ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
White Spruce ◽  
Eastern Spruce Budworm ◽  
Laboratory Colony

A manipulative field study was carried out to determine whether the foliar endophyte fungus, Phialocephala scopiformis DAOM 229536, decreased the performance of eastern spruce budworm, Choristoneura fumiferana larvae developing on white spruce trees. Overwintered second-instar budworm larvae from a laboratory colony or from a wild population were placed on endophyte positive or negative trees one or two weeks before budburst. The presence of the endophyte in the needles reduced the survival of C. fumiferana from both a wild population and a laboratory colony. Survival for budworm juveniles up to pupation and to adult emergence was 13% and 17% lower, respectively, on endophyte positive trees. The endophyte did not influence the size or sex of survivors and budworm survival was not influenced by any two- or three-way interactions. Budworm survival was higher for wild than for laboratory-reared budworm and for budworm placed on trees a week before budburst. This may be the first field study to demonstrate the efficacy of an endophytic fungus against wild individuals of a major forest insect pest. The efficacy of the endophyte at low larval densities suggests that it could be a useful tactic to limit spruce budworm population growth in the context of an early intervention strategy.

Ultrastructural Effects of a Non-Steroidal Ecdysone Agonist, RH-5992, on the Sixth Instar Larva of the Spruce Budworm, Choristoneura fumiferana

1997 ◽  
Vol 43 (1) ◽  
pp. 55-68 ◽  
Author(s):  
A Retnakaran ◽  
A MacDonald ◽  
W.L Tomkins ◽  
C.N Davis ◽  
A.J Brownwright ◽  
...  
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Instar Larva ◽  
Ecdysone Agonist

PATHOGENICITY OF NOSEMA FUMIFERANAE (THOMSON) (MICROSPORIDA) IN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEMENS), AND IMPLICATIONS OF DIAPAUSE CONDITIONS

1988 ◽  
Vol 120 (3) ◽  
pp. 221-229 ◽  
Author(s):  
Leah S. Bauer ◽  
Gerald L. Nordin
Keyword(s):  
Development Time ◽  
Linear Models ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Instar Larva ◽  
Developmental Time ◽  
Pupal Weight ◽  
Adult Longevity ◽  
Time Duration ◽  
Eastern Spruce Budworm

AbstractA standardized bioassay procedure was used to determine median lethal doses (LD50) of the microsporidium, Nosema fumiferanae (Thom.), on newly molted fourth- and fifth-instar eastern spruce budworm larvae (Choristoneura fumiferana (Clem.)). The LD50 for fifth-instar larva was 1.23 × 106 ± 2.82 × 105 spores. The fourth-instar LD50 was 2.23 × 104 ± 4.30 × 103 spores per larva for populations experiencing prolonged post-diapause cold storage or an elevated temperature during diapause and 2.00 × 105 ± 6.66 × 104 spores per larva for populations not experiencing stressful conditions during and after diapause. Median lethal times (LT50) ranged from 6 to 19 days, depending on instar and dose level. Sublethal responses of fourth- and fifth-instar larvae inoculated with serial dilutions of spores were estimated by significant linear models. These regressions were negative for pupal weight and adult longevity and positive for development time (duration of instar VI). Inoculations of newly molted sixth-instar larvae produced similar models, although development time was not significantly affected. Insects reared following stress during and after diapause had consistently longer developmental times. The importance of prolonged developmental time on disease expression and insect susceptibility is discussed.

CARPENTER ANTS AS PREDATORS OF SPRUCE BUDWORM IN THE BOREAL FOREST OF NORTHWESTERN ONTARIO

1992 ◽  
Vol 124 (6) ◽  
pp. 1093-1100 ◽  
Author(s):  
C.J. Sanders ◽  
A. Pang
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Western North America ◽  
Tree Crown ◽  
Carpenter Ants ◽  
Northwestern Ontario ◽  
Large Numbers ◽  
Laboratory Colony

AbstractIn the boreal forest of northwestern Ontario, where carpenter ants (Camponotus spp.) construct extensive underground tunnels, few worker ants were seen on the aerial portions of trees containing colonies of the ants or on neighboring trees, even though the trees were infested by large numbers of spruce budworm [Choristoneura fumiferana (Clem.)] larvae. Immunochemical techniques detected less spruce budworm soluble protein in worker ants from this area than in a laboratory colony that had been fed budworm larvae, or in a colony located in a spruce tree that was surrounded by gravel where the ants were unable to build underground tunnels and instead foraged extensively in the tree crown. This suggests that, in contrast to evidence from western North America, carpenter ants in the boreal forests of northwestern Ontario, and perhaps elsewhere throughout the range of the spruce budworm, are of limited importance as predators of the spruce budworm.

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