scholarly journals Quantifying and predicting population connectivity of an outbreaking forest insect pest

2021 ◽  
Author(s):  
Jeremy Larroque ◽  
Julian Wittische ◽  
Patrick M. A. James
Keyword(s):  
Population Dynamics ◽  
Landscape Connectivity ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Management Strategies ◽  
Temporal Stability ◽  
Spruce Budworm ◽  
Population Connectivity ◽  
Outbreak Area ◽  
Future Landscape

Abstract Context Dispersal has a key role in the population dynamics of outbreaking species such as the spruce budworm (Choristoneura fumiferana) as it can synchronize the demography of distant populations and favor the transition from endemic to epidemic states. However, we know very little about how landscape structure influences dispersal in such systems while such knowledge is essential for better forecasting of spatially synchronous population dynamics and to guide management strategies. Objectives We aimed to characterize the spatial environmental determinants of spruce budworm dispersal to determine how these features affect outbreak spread in Quebec (Canada). We then apply our findings to predict expected future landscape connectivity and explore its potential consequences on future outbreaks. Methods We used a machine-learning landscape genetics approach on 447 larvae covering most of the outbreak area and genotyped at 3562 SNP loci to identify the main variables affecting connectivity. Results We found that the connectivity between outbreak populations was driven by the combination of precipitation and host cover. Our forecasting suggests that between the current and next outbreaks, connectivity may increase between Ontario and Quebec, and might decrease in the eastern part, which could have the effect of limiting outbreak spread from Ontario and Quebec to the eastern provinces. Conclusions Although we did not identify any discrete barriers, low connectivity areas might constrain dispersal in the current and future outbreaks and should in turn, be intensively monitored. However, continued sampling as the outbreak progresses is needed to confirm the temporal stability of the observed patterns.

A METHOD FOR REARING THE LARVAL STAGES OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE), FOR PHYSIOLOGICAL STUDIES

1990 ◽  
Vol 122 (6) ◽  
pp. 1271-1272 ◽  
Author(s):  
Hemendra Mulye ◽  
Roger Gordon
Keyword(s):  
Population Dynamics ◽  
North America ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Spruce Budworm ◽  
Forest Pest ◽  
Forest Insect ◽  
Larval Stages ◽  
Eastern Spruce Budworm ◽  
Physiological Studies

The eastern spruce budworm, Choristoneura fumiferana Clemens, is the most widely distributed and destructive forest insect pest in North America. Although much is known about the ecology, population dynamics, and impact of C. fumiferana on tree growth (Sanders et al. 1985), there is very little information available on the physiology of this forest pest. Physiological studies are crucial to the development of novel strategies for spruce budworm control.

scholarly journals Forest management strategies to reduce spruce budworm damage in the Fundy Model Forest

1996 ◽  
Vol 72 (4) ◽  
pp. 399-405 ◽  
Author(s):  
David A. MacLean
Keyword(s):  
Decision Support ◽  
Forest Management ◽  
Decision Support System ◽  
Support System ◽  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Spruce Budworm ◽  
Stand Age ◽  
Timber Supply

Spruce budworm (Choristoneura fumiferana) outbreaks cannot be prevented, but the amount of damage that occurs can be managed. Tree species, stand age, hardwood content, and drainage class, as well as the outbreak severity and length, determine the amount of tree mortality during budworm outbreaks. Silviculture and forest management can be used to reduce the incidence of the most damaged stand types across the landscape. The amount of defoliation in mixed balsam fir-hardwood stands is strongly negatively related to hardwood content, especially with hardwoods > 40%. The Spruce Budworm Decision Support System (DSS) links models of stand and forest response to budworm outbreaks and inventory interpretation to a GIS, and can be used to evaluate effects of outbreaks and management on forest structure and timber supply. An example using the Spruce Budworm DSS for a portion of the Fundy Model Forest indicated that losses from a future budworm outbreak could be reduced 34% by directing harvesting and silviculture towards conversion of one-half of the most vulnerable stand types into low susceptibility or non-susceptible species. Key words: decision support system, vulnerability, silviculture, insect damage

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

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin
Keyword(s):  
Boreal Forests ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
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.

INTERACTIONS BETWEEN BACILLUS THURINGIENSIS BERLINER AND APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE), A PARASITOID OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE)

1990 ◽  
Vol 122 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Vincent Nealis ◽  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Negative Impact ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Fourth Instar ◽  
Mortality Factors ◽  
Commercial Formulation ◽  
Beneficial Effects

AbstractInteractions between Bacillus thuringiensis Berliner and Apanteles fumiferanae Viereck as mortality factors of the spruce budworm, Choristoneura fumiferana (Clemens), were investigated by placing parasitized and nonparasitized budworm larvae on foliage with and without spray deposits of a commercial formulation of B. thuringiensis. The effect of larval age (and, thus, the timing of spray applications) was examined by using peak third-instar and peak fourth-instar larvae. We demonstrated that parasitized larvae are more likely to survive exposure to B. thuringiensis because they feed less than non-parasitized larvae and are thus less likely to acquire a lethal dose of the bacterium. Bacillus thuringiensis nevertheless reduced parasitoid populations by 50–60% by killing their hosts before parasitoid emergence. This negative impact of B. thuringiensis on parasitoid survival was decreased when exposure of budworm larvae to spray deposits was delayed from peak third to peak fourth instar. The enhanced survival of parasitoids offset the lower mortality as a result of B. thuringiensis in the delayed sprays. We conclude that B. thuringiensis applied when budworm larval populations are at peak fourth instar or later would complement rather than interfere with the beneficial effects of A. fumiferanae. The implications for budworm management strategies are discussed.

scholarly journals More than Moran: coupling statistical and simulation models to understand how defoliation spread and weather variation drive insect outbreak dynamics

2018 ◽  
Vol 48 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Hedvig K. Nenzén ◽  
Pedro Peres-Neto ◽  
Dominique Gravel
Keyword(s):  
Choristoneura Fumiferana ◽  
Abiotic Factors ◽  
Management Strategies ◽  
Simulation Models ◽  
Spruce Budworm ◽  
Statistical Simulation ◽  
Efficient Management ◽  
Regional Dynamics ◽  
Weather Variation

Understanding the processes that underlie species fluctuations is crucial to the development of efficient management strategies for outbreaks of destructive forest pests. Yet, the role of biotic and abiotic factors as well as their interactions in synchronizing outbreaks is not understood, despite many empirical and theoretical studies of species fluctuations. Here, we use a combined statistical–simulation model to investigate how defoliation spread and autocorrelated weather affect outbreaks of a major defoliator of North American boreal forest, the spruce budworm (Choristoneura fumiferana (Clemens)). We modelled the regional dynamics of spruce budworm and based the model on data collected from spatiotemporal aerial surveys of defoliation from 1968–2015 in Quebec, Canada. The effects of weather on local forest stand defoliation and mortality transitions, along with defoliation spread probability and distance, were estimated statistically. Simulations were run with these estimates to identify the effects of spatiotemporal weather autocorrelation on synchronicity of outbreaks. Defoliation spread together with weather variables was found to best fit the observed outbreak size. Simulation models suggest that positive temporal autocorrelation in weather promotes outbreaks, indicating that a series of suitable years could encourage outbreaks.

A GEOGRAPHICAL CLINE IN EGG WEIGHTS IN CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE) AND ITS SIGNIFICANCE IN POPULATION DYNAMICS

1983 ◽  
Vol 115 (9) ◽  
pp. 1103-1108 ◽  
Author(s):  
G. T. Harvey
Keyword(s):  
Population Dynamics ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Pupal Weight ◽  
Egg Weight ◽  
Winter Conditions ◽  
The Mean

AbstractThe mean weights of the initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), vary within and between populations. Measurements of collections from across the range of this species reveal the presence of a cline directly related to latitude and longitude of the collection source. Collection mean Ei values range from 0.219 mg in the northwest to 0.157 mg in the southeast. A similar cline, also related to latitude but negative in slope, is demonstrated for the number of eggs per unit pupal weight. This cline also finds expression in changing slope of fecundity/pupal weight regressions. The cline in egg weight appears to be an adaptation to winter conditions across the range of this insect and should be considered in population dynamics.

Périodicité et synchronisme des épidémies de la tordeuse des bourgeons de l'épinette au Québec

2003 ◽  
Vol 33 (10) ◽  
pp. 1947-1961 ◽  
Author(s):  
Yves Jardon ◽  
Hubert Morin ◽  
Pierre Dutilleul
Keyword(s):  
Population Dynamics ◽  
Choristoneura Fumiferana ◽  
Local Population ◽  
Spruce Budworm ◽  
Periodic Component ◽  
Moran Effect ◽  
Regional Effect ◽  
Migration Effect ◽  
Different Types ◽  
Insect Populations

A time series analysis was performed on 32 dendrochronological chronologies using Dutilleul's multi frequential periodo gram. Our aim was to estimate the periodicities of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks in the province of Quebec. Our analysis estimated a signal of 25-38 years corresponding to spruce budworm outbreaks. Analyses conducted in the 20th century indicated the existence of true periodicities in half of the series suggesting local population dynamics. These periodicities were estimated to be 29-34 years. For the other series, outbreaks were explained by the addition of a second periodic component to the fundamental periodicity. These combined periodicities (pseudoperiodicities or complex periodicities) described most of the 130-year series analysed. The lack of several outbreaks explained part of the combined periodicity. The results suggest a migration effect and complex local population dynamics. A third periodic component explains the double epidemic waves. These estimated periodicities are often similar and in phase. We believe that a common regional effect (the Moran effect) acts on the minor fluctuations of the insect populations and helps synchronize the outbreaks. This research shows that different types of outbreak dynamics can be found within a same insect species.

INTERACTION OF EVENING GROSBEAK (HESPERIPHONA VESPERTINA) AND SPRUCE BUDWORM (CHORISTONEURA FUMIFERANA (CLEM.)) IN A LOCALIZED BUDWORM OUTBREAK TREATED WITH DDT IN QUEBEC

1964 ◽  
Vol 42 (6) ◽  
pp. 1017-1024 ◽  
Author(s):  
J. R. Blais ◽  
G. H. Parks
Keyword(s):  
Chemical Treatment ◽  
Critical Period ◽  
Direct Evidence ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Combined Effects ◽  
Natural Control ◽  
Control Factors ◽  
Outbreak Area ◽  
Large Numbers

Control of a localized spruce budworm outbreak in southeastern Quebec was achieved through the combined effects of chemical treatment with DDT and natural control factors. Amongst the latter, predation by evening grosbeaks was suspected to have been of considerable importance. It appears that the birds were attracted to the outbreak area in unusually large numbers during their spring migration. The yearly influx of the grosbeaks in the area occurred when the budworm was in the late larval and the pupal stages, an especially critical period with respect to generation survival of this insect. In 1963, the year following collapse of the outbreak, very few grosbeaks were seen in the area. There was no direct evidence that the birds suffered ill effects from the spraying operation.

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.

Sign in / Sign up

Export Citation Format

Share Document