Derivation of Pheromone-Based Larval Thresholds in Spruce Budworm Accounting for Distance to Defoliated Forest Stands

Intervention Strategy ◽

Spruce Budworm ◽

Interactive Effects ◽

The Novel ◽

Forest Stands ◽

General Guideline ◽

Number Of Males

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 > 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.

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

10.4039/ent971281-12 ◽

1965 ◽

Vol 97 (12) ◽

pp. 1281-1293 ◽

Cited By ~ 8

Author(s):

A. P. Randall

Keyword(s):

New Brunswick ◽

Large Scale ◽

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.

FIELD RESPONSE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), TO DOSAGE AND VOLUME RATES OF COMMERCIAL BACILLUS THURINGIENSIS

10.4039/ent116983-7 ◽

1984 ◽

Vol 116 (7) ◽

pp. 983-990 ◽

Cited By ~ 6

Author(s):

O. N. Morris

Keyword(s):

Bacillus Thuringiensis ◽

Abies Balsamea ◽

Spruce Budworm ◽

Balsam Fir ◽

Forest Stands ◽

Effective Application ◽

Field Response

AbstractThuricide and Dipel, formulations of Bacillus thuringiensis (B.t.), were applied aerially against the spruce budworm, Choristoneura fumiferana (Clem.), in forest stands of balsam fir, Abies balsamea L. A dosage of 30 Billion International Units (BIU) of B.t./ha applied in 2.4 to 4.7 L of spray/ha was most effective. Application of 20 BIU/ha was marginally effective against a population of 12 to 36 larvae/45 cm of branch.

RELEASE RATES AND ATTRACTION OF PVC LURES CONTAINING SYNTHETIC SEX ATTRACTANT OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

10.4039/ent113103-2 ◽

1981 ◽

Vol 113 (2) ◽

pp. 103-111 ◽

Cited By ~ 33

Author(s):

C. J. Sanders

Keyword(s):

Sex Attractant ◽

Spruce Budworm ◽

Field Trapping ◽

Direct Proportion ◽

Release Rates ◽

Time Intervals ◽

Lower Temperature ◽

Number Of Males ◽

Over Time

AbstractRelease rates of synthetic attractant of the spruce budworm, Choristoneura fumiferana (Clem.), from a PVC formulation were determined by weight loss. They varied in direct proportion to the initial concentration of the attractant and also with the size of the pellet. Release rates declined by about 50% over the time intervals of 10–40 days and 40–100 days. Initially they were two to three times lower at 10°C than at 21°C, but were far more constant over time at the lower temperature. A pellet weighing 130 mg containing 42 μg of attractant released an estimated .1–1 μg/day, or 4–40 ng/h, which is close to the rate of emission by a calling female (Silk et al. 1980), and field trapping data showed that a lure this size attracted the same number of males as a calling female.

Comparative Appraisal of Insecticidal Operations Against Spruce Budworm in Quebec During Two Outbreaks

The Forestry Chronicle ◽

10.5558/tfc53071-2 ◽

1977 ◽

Vol 53 (2) ◽

pp. 71-76

Author(s):

J. R. Blais

Keyword(s):

Large Scale ◽

Spruce Budworm ◽

Single Treatment ◽

Treatment Area ◽

Residual Properties

Large-scale aerial applications of chemical insecticides against spruce budworm (Choristoneura fumiferana (clem.)) took place in Quebec during two outbreaks, 1952-58 (Outbreak I) and 1970-75 and continuing (Outbreak II), in an effort to prevent extensive mortality of fir and spruce. During Outbreak I yearly treatment consisted of one application of DDT at 0.6 kg/ha (8 oz./ac.); during Outbreak II it consisted of two applications of organophosphates and carbamates (mostly fenitrothion) for a total of 0.3 kg/ha (4 oz./ac.). The effects of a single treatment were evident for two years in Outbreak I because of residual properties of DDT, while in Outbreak II, effects were evident only in the year of application. Reduction in budworm populations due to treatment was considerably greater during Outbreak I than during Outbreak II. Average foliage protection in the year of treatment and in the following year was 38% and 60% respectively in Outbreak I, while it was 15% and 0% in Outbreak II. Spray operations in any one treatment area were repeated after an interval of three or four years due to population build up in Outbreak I; continuously high populations necessitated yearly applications of insecticides in Outbreak II. It is suggested that the current spraying policy in Quebec should be reappraised in the light of conditions that prevail.

Insect toxins from spruce endophytes

Canadian Journal of Chemistry ◽

10.1139/v03-044 ◽

2003 ◽

Vol 81 (4) ◽

pp. 284-292 ◽

Cited By ~ 41

Author(s):

John A Findlay ◽

Guoqiang Li ◽

J David Miller ◽

Taiwo O Womiloju

Keyword(s):

Black Spruce ◽

Spruce Budworm ◽

White Spruce ◽

Fungal Endophyte ◽

The Novel ◽

Macrocyclic Antibiotic ◽

Insect Toxins ◽

Spruce Needles

Extracts of fermentation cultures of a fungal endophyte (DAOM 221611) from spruce needles have afforded the known macrocyclic antibiotic vermiculin (1), 7α,8β,11-trihydroxydrimane (2), and eight novel 13-carbon γ-lactones, namely trans-3-methyldodec-cis-6-en-4-olide (3), trans-8-hydroxy-3-methyldodec-cis-6-en-4-olide (4), trans-8-acetoxy-3-methyldodec-cis-6-en-4-olide (5), trans-9-hydroxy-3-methyl-8-oxo-dodec-trans-6-en-4-olide (6), trans-8,9-dihydroxy-3-methyldodec-cis-6-en-4-olide (7), trans-9-hydroxy-8-oxo-3-methyldodecan-4-olide (8), trans-7,9-dihydroxy-3-methyl-8-oxo-dodecan-4-olide (9), and trans-6-hydroxymethyl-3-methyl-7-oxo-undecan-4-olide (10). A known JH III metabolism product, 10,11-dihydroxyfarnesenic acid (11), was also isolated and synthesized from farnesol. Other endophyte cultures from black spruce and white spruce afforded the novel 6,7-dihydroxy-2-propyl-2,4-octadien-4-olide (16), 5,6,8-trihydroxy-4-(1'-hydroxyethyl) isocoumarin (17) plus the known sescandelin (18), sescandelin B (19), and 4-hydroxy-2-methoxyacetanilide (20). Several of the γ-lactones showed toxicity to spruce budworm (Choristoneura fumiferana Clem.) larvae and vermiculin 1 and compound 16 were toxic to spruce budworm cells.Key words: toxigenic endophytes, insect toxins, γ-lactones, isocoumarins.

Vulnerability of Conifer Regeneration to Spruce Budworm Outbreaks in the Eastern Canadian Boreal Forest

Forests ◽

10.3390/f10100850 ◽

2019 ◽

Vol 10 (10) ◽

pp. 850 ◽

Cited By ~ 14

Author(s):

Janie Lavoie ◽

Miguel Montoro Girona ◽

Hubert Morin

Keyword(s):

Boreal Forests ◽

Black Spruce ◽

Management Strategies ◽

Abies Balsamea ◽

Spruce Budworm ◽

Balsam Fir ◽

Insect Outbreaks ◽

Spruce Stands ◽

Canadian Boreal Forest

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.

LABORATORY BIOASSAY OF THE SEX PHEROMONE OF THE FEMALE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

10.4039/ent103631-5 ◽

1971 ◽

Vol 103 (5) ◽

pp. 631-637 ◽

Cited By ~ 14

Author(s):

C. J. Sanders

Keyword(s):

Sex Pheromone ◽

Spruce Budworm ◽

Maximum Response ◽

Continuous Illumination ◽

Natural Lighting ◽

Eastern Spruce Budworm ◽

Minor Peak ◽

A Minor ◽

Number Of Males

AbstractA simple and inexpensive olfactometer based on that of Gaston and Shorey (1964) is described for bioassaying the sex pheromone of the eastern spruce budworm. The number of males buzzing (rapidly beating their wings while circling on the substrate) after the introduction of the sample into the airstream of the olfactometer was used as measure of response. Males held under continuous illumination showed maximum response when 2 to 3 days old. Under natural lighting males showed a circadian rhythm, with peak response shortly after dark and a minor peak in mid-morning. Since per cent response under continuous illumination exceeded the maximum response under natural lighting, it is recommended that bioassays be carried out with 2- to 3-day-old males held under continuous illumination.

BEHAVIOURAL EFFECTS OF SECONDARY COMPONENTS OF THE SEX PHEROMONE OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

10.4039/ent1151053-9 ◽

1983 ◽

Vol 115 (9) ◽

pp. 1053-1058 ◽

Cited By ~ 9

Author(s):

A. R. Alford ◽

P. J. Silk ◽

M. McClure ◽

C. Gibson ◽

J. Fitzpatrick

Keyword(s):

Sex Pheromone ◽

Wind Tunnel ◽

Spruce Budworm ◽

Field Observations ◽

Eastern Spruce Budworm ◽

Behavioural Effects ◽

Low Levels ◽

Number Of Males

AbstractLaboratory wind tunnel and field observations have demonstrated an important behavioural role of tetradecanal (14:Ald) in the chemical communication system of the spruce budworm, Choristoneura fumiferana (Clemens). A greater number of males initiated upwind flight and continued on to contact the source when 14:Ald was present than with 95/5 E/Z11-tetradecenal (E/Z11-14:Ald) alone. The presence of E11-tetradecen-1-ol acetate (E11-14:Ac) decreased the males' responsiveness to the aldehydes. Its effect appeared to be attenuated, when present at low levels with 95/5 E/Z11-14:Ald, by the presence of 14:Ald, but it is still unclear what effects low levels of E11-14:Ac have on male behaviour.

Positive Results of an Early Intervention Strategy to Suppress a Spruce Budworm Outbreak after Five Years of Trials

Forests ◽

10.3390/f10050448 ◽

2019 ◽

Vol 10 (5) ◽

pp. 448 ◽

Cited By ~ 12

Author(s):

David A. MacLean ◽

Peter Amirault ◽

Luke Amos-Binks ◽

Drew Carleton ◽

Chris Hennigar ◽

...

Keyword(s):

Early Intervention ◽

New Brunswick ◽

Intervention Strategy ◽

Abies Balsamea ◽

Spruce Budworm ◽

Treatment Programs ◽

Native Forest ◽

Insecticide Treatment ◽

Salvage Harvesting

Spruce budworm (Choristoneura fumiferana Clem.; SBW) outbreaks are one of the dominant natural disturbances in North America, having killed balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) trees over tens of millions of hectares. Responses to past SBW outbreaks have included the aerial application of insecticides to limit defoliation and keep trees alive, salvage harvesting of dead and dying trees, or doing nothing and accepting the resulting timber losses. We tested a new ‘early intervention strategy’ (EIS) focused on suppressing rising SBW populations before major defoliation occurs, from 2014 to 2018 in New Brunswick, Canada. The EIS approach included: (1) intensive monitoring of overwintering SBW to detect ‘hot spots’ of low but rising populations; (2) targeted insecticide treatment to prevent spread; and (3) proactive public communications and engagement on project activities and results. This is the first attempt of area-wide (all areas within the jurisdiction of the province of New Brunswick) management of a native forest insect population. The project was conducted by a consortium of government, forest industry, researchers, and other partners. We developed a treatment priority and blocking model to optimize planning and efficacy of EIS SBW insecticide treatment programs. Following 5 years of over 420,000 ha of EIS treatments of low but increasing SBW populations, second instar larvae (L2) SBW levels across northern New Brunswick were found to be considerably lower than populations in adjacent Québec. Treatments increased from 4500 ha in 2014, to 56,600 ha in 2016, and to 199,000 ha in 2018. SBW populations in blocks treated with Bacillus thuringiensis or tebufenozide insecticide were consistently reduced, and generally did not require treatment in the subsequent year. Areas requiring treatment increased up to 2018, but SBW L2 populations showed over 90% reductions in that year. Although this may be a temporary annual decline in SBW population increases, it is counter to continued increases in Québec. Following 5 years of tests, the EIS appears to be effective in reducing the SBW outbreak.

Spatiotemporal variability in tree and stand mortality caused by spruce budworm outbreaks in eastern Quebec

Canadian Journal of Forest Research ◽

10.1139/x09-178 ◽

2010 ◽

Vol 40 (1) ◽

pp. 86-94 ◽

Cited By ~ 35

Author(s):

Mathieu Bouchard ◽

David Pothier

Keyword(s):

Large Scale ◽

Abies Balsamea ◽

Spruce Budworm ◽

Aerial Photographs ◽

Spatiotemporal Variability ◽

Tree Age ◽

Mature Trees ◽

Historical Trends ◽

Understory Tree

We evaluated spruce budworm ( Choristoneura fumiferana (Clem.)) outbreak effects in nine study areas (60–86 ha each) located in the boreal forest of eastern Quebec (Canada). In each area, spruce budworm outbreak effects were measured from vegetation plots, dominant canopy and understory tree age structures, retrospective analysis of aerial photographs, defoliation records, and host tree growth reductions (dendrochronology). Large-scale synchronous outbreaks were detected across the region around the years 1880, 1915, 1950, and 1980. Overall, contrarily to what was expected for a region where host species (balsam fir ( Abies balsamea (L.) Mill.), Picea spp.) content is relatively high, these spruce budworm outbreaks seemed to have a relatively minor influence on stand dynamics, with the exception of the most recent outbreak (1980). This outbreak resulted in major stand mortality in the southern part of the region and favored the establishment of extensive tracts of young even-aged stands with few residual mature trees. This very abrupt increase in outbreak severity compared with earlier outbreaks, perhaps due to climatic or random factors, suggests that historical trends in successive outbreak severity should be extrapolated very cautiously and that the study of several outbreak cycles is needed to establish a range of natural variability that can be used to develop an ecosystem forest management strategy.