Larval diet prior to and following virus ingestion influences the efficacy of two nucleopolyhedroviruses in whitemarked tussock moth (Orgyia leucostigma) caterpillars

2012 ◽  
Vol 144 (3) ◽  
pp. 447-457 ◽  
Author(s):  
Garrett Brodersen ◽  
Rob Johns ◽  
Renée Lapointe ◽  
David Thumbi ◽  
Graham Thurston ◽  
...  
Keyword(s):  
Artificial Diet ◽  
Viral Infections ◽  
Abies Balsamea ◽  
Field Studies ◽  
Balsam Fir ◽  
Betula Papyrifera ◽  
White Birch ◽  
Tussock Moth ◽  
Orgyia Leucostigma ◽  
Whitemarked Tussock Moth

AbstractFood quality can influence the performance of immature insects and their interactions with pathogens, such as viruses. In manipulative field studies, virus-free caterpillars of the whitemarked tussock moth (WMTM) (Orgyia leucostigma (Smith)) had higher survival, more female-biased sex ratios, and were larger when feeding on white birch (Betula papyrifera Marshall) versus balsam fir (Abies balsamea (Linnaeus) Miller) or red spruce (Picea rubens Sargent). Subsequent laboratory studies with two nucleopolyhedroviruses, derived from WMTMs and Douglas-fir tussock moths, indicated that caterpillars fed high quality food (i.e., artificial diet) prior to infection had less mortality associated with virus infection than those feeding on lower quality foliage (i.e., birch). In field studies, caterpillars fed birch following infection had significantly lower mortality than those feeding on relatively lower quality foliage (i.e., balsam fir). We postulate that higher nutritional quality in artificial diet relative to birch (previrus-ingestion nutrition) and in birch relative to balsam fir foliage (postvirus-ingestion nutrition) has a positive effect on the ability of tussock moth caterpillars to resist or recover from viral infections, although the specific mechanisms responsible for observed resistance remain unclear.

Incidence and impact of Entomophaga aulicae (Zygomycetes: Entomophthorales) and a nucleopolyhedrovirus in an outbreak of the whitemarked tussock moth (Lepidoptera: Lymantriidae)

2002 ◽  
Vol 134 (6) ◽  
pp. 825-845 ◽  
Author(s):  
K. van Frankenhuyzen ◽  
P. Ebling ◽  
G. Thurston ◽  
C. Lucarotti ◽  
T. Royama ◽  
...  
Keyword(s):  
Mass Density ◽  
Abies Balsamea ◽  
Larval Survival ◽  
Balsam Fir ◽  
Egg Mass ◽  
Population Changes ◽  
Tussock Moth ◽  
Orgyia Leucostigma ◽  
Recent Outbreak ◽  
Whitemarked Tussock Moth

AbstractIn Nova Scotia, the whitemarked tussock moth, Orgyia leucostigma Fitch, periodically erupts in outbreaks that typically last 3–5 years. Population changes during a recent outbreak were monitored by means of aerial defoliation surveys and fall egg-mass surveys that were conducted between 1997 and 2001. Severe defoliation was first recorded on approximately 250 ha in 1996. The defoliated area increased rapidly to hundreds of thousands hectares in 1998, after which it sharply declined to about 4700 ha in 2000 and 0 ha in 2001. The total infested area [>0.01 egg masses per three branches of Abies balsamea L. (Pinaceae)] decreased from about 1.4 million ha in 1997 to about 13 500 ha in 2001. Between 1996 and 2001, the infestation involved a cumulative total of 2.4 million ha, covering most of the province. The collapse of larval populations during 1998 was associated with widespread prevalence of a singly embedded nucleopolyhedrovirus (NPV) and Entomophaga aulicae (Reichardt in Bail) Humber (Zygomycetes: Entomophthorales). Sampling of larval populations in late July and August 1998 revealed a widespread and virtually sympatric occurrence of those pathogens in areas that were under defoliation pressure, with infection levels by each pathogen exceeding 75% in many sample sites. Pathogen impacts on larval survival were studied in 1999 in a persisting pocket of severe infestation in Hants County. Larvae were collected every 3 d from balsam fir branch samples between 17 June and 21 July and reared to determine cause of death. The two pathogens together accounted for at least 50% of cohort mortality, calculated as marginal mortality rates according to Royama (2001). Although cohort mortality due to disease on balsam fir was significantly correlated with between-generation reduction in mean egg-mass density, overall pathogen-induced mortality was not high enough to drive the populations into an endemic state, and a moderate infestation persisted into 2000.

Effects of fenitrothion on the arthropod food of tree-foraging forest songbirds

1990 ◽  
Vol 68 (11) ◽  
pp. 2235-2242 ◽  
Author(s):  
Rhonda L. Millikin
Keyword(s):  
Active Ingredient ◽  
Significant Relationship ◽  
Tree Species ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Betula Papyrifera ◽  
White Birch ◽  
Forest Songbirds ◽  
The Impact

The impact of fenitrothion on the arthropod food of songbirds was measured using white birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.) branch sample and drop trays. Following ground application of fenitrothion at 293 g active ingredient/ha, there was a significant decrease in the biomass of arthropods as determined using branch samples from both tree species, but not until 5 days after the application (29% reduction for balsam fir, 35% for white birch). Samples from drop trays indicated an immediate kill of arthropods not associated with the tree. Most remaining arthropods on treated balsam fir trees were dead. These dead arthropods would not be suitable food for birds that require movement to detect their prey. There was no significant relationship between amount of deposit (treated trees only) and the reduction of arthropods for either tree species.

Does spruce budworm (Lepidoptera: Tortricidae) rearing diet influence larval parasitism?

2013 ◽  
Vol 145 (5) ◽  
pp. 539-542 ◽  
Author(s):  
M. Lukas Seehausen ◽  
Jacques Régnière ◽  
Éric Bauce
Keyword(s):  
Significant Influence ◽  
Artificial Diet ◽  
Food Source ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Field Studies ◽  
Balsam Fir ◽  
Choice Test ◽  
Larval Parasitoid

AbstractArtificial diet is commonly used to rear the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), in the laboratory. While its effect on spruce budworm performance is relatively well studied, no information exists about the influence of rearing diet on larval parasitism. In this study, spruce budworm larvae reared in the laboratory on artificial diet or balsam fir, Abies balsamea (Linnaeus) Miller (Pinaceae), foliage were introduced in the field to compare parasitism. Additionally, a laboratory choice test was conducted with the larval parasitoid Tranosema rostrale (Brischke) (Hymenoptera: Ichneumonidae). No significant influence of spruce budworm rearing diet on parasitism in the field was found. However, in the laboratory, T. rostrale attacked significantly more foliage-fed larvae. We conclude that even if initial differences in parasitism may exist between diet-fed and foliage-fed larvae in the laboratory, spruce budworm larvae reared on artificial diet can be used in field studies investigating parasitism of wild spruce budworm populations without concern that the food source would affect parasitism.

scholarly journals Dynamique d'établissement d'un peuplement bi-étagé de bouleau blanc et de sapin baumier en zone boréale

1993 ◽  
Vol 69 (2) ◽  
pp. 173-177 ◽  
Author(s):  
Louis Bélanger ◽  
Daniel Allard ◽  
Philippe Meek
Keyword(s):  
Age Structure ◽  
Initial Period ◽  
Abies Balsamea ◽  
Floristic Composition ◽  
Balsam Fir ◽  
White Birch ◽  
Vegetation Dynamic ◽  
Local Conditions ◽  
Regeneration Pattern ◽  
Seed Sources

The age structure of a boreal two-storied stand formed by an upperstory of white birch (Betula papyrifera Marsh.) with an understory of balsam fir (Abies balsamea (L.) Mill.) was analysed. The establishment of this 50-year stand followed a burn that ran through a cut-over area. The objective was to verify if the establishment of the fir understory followed the traditional succession model or the initial floristic composition model. The age structure analysis indicated an immediate and rapid establishment of white birch during a period of 6 years after the fire. Establishment of fir, however, was initiated only 16 years after the fire. Peak establishment was 33 years after the fire. Fir regeneration followed a cycle. The regeneration pattern was characterized by the absence of fir establishment the first 16 years after the fire, followed by sporadic fir regeneration the next 12 years, then by a 13-year period of abundant regeneration after which there was a complete halt to fir regeneration. So, in this case, the successional model was more fit to describe the dynamics of balsam fir. The absence of fir regeneration during the initial period after the fire could be explained by the absence of the nearby fir seed sources due to harvesting. However, the total absence of fir establishment during the last period is more difficult to explain. Seedbed evolution since the fire could possibly be in cause. This and other studies indicate that in the boreal balsam fir-white birch ecoclimatic domain vegetation dynamic after fire does not limit itself to one pathway. Stand regeneration after fire is significantly affected by local conditions.

Long-term impact of fire on high-altitude balsam fir (Abies balsamea) forests in south-central Quebec deduced from soil charcoal

2013 ◽  
Vol 43 (2) ◽  
pp. 188-199 ◽  
Author(s):  
Pierre-Luc Couillard ◽  
Serge Payette ◽  
Pierre Grondin
Keyword(s):  
Boreal Forest ◽  
High Altitude ◽  
Tree Species ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Forest Landscape ◽  
White Birch ◽  
Soil Charcoal ◽  
Fire Activity

Extensive balsam fir (Abies balsamea (L.) Mill.) stands across the southern boreal forest are ecosystems likely more influenced by insect outbreaks and windthrows than by fire. To what degree the dominance of balsam fir stands reflects past and present disturbance dynamics associated with fire is not well documented. To answer this question, we focused on the reconstruction of the long-term fire history of high-altitude balsam fir forests of southern Quebec. The reconstruction was based on botanically identified and radiocarbon-dated soil charcoal particles in 19 sites covering successional stages from white birch (Betula payrifera Marsh.) to mixed white birch – balsam fir stands. Fire activity commenced early after deglaciation, about 9600 calibrated years before present when the first boreal tree species were established. Fire occurred recurrently during the following 5000 years with a forest landscape composed of the principal tree species common to the boreal forest, including jack pine (Pinus banksiana Lamb.). Fire activity ceased more or less abruptly about 4500 years ago due to less fire-conducive, more humid conditions. Then, the forest landscape progressively changed towards a larger representation of white birch – balsam fir forests and the disappearance of jack pine. Whereas several balsam fir stands have not burned over the last 4500 years, scattered fires occurred in particular over the last 250 years when 1815 and 1878 fires, probably man-made, burned 50% of the forest, thus causing a major change in the composition of the forest landscape. It is concluded that the high-altitude forest landscape of southern Quebec changed profoundly over the Holocene in close association with a time-transgressive dry-to-wet climatic gradient.

Dynamique de la sapinière à bouleau jaune de l'est après une épidémie de tordeuse des bourgeons de l'épinette

1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
The Other ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
White Birch ◽  
Yellow Birch ◽  
Mixed Stands ◽  
The Dead

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.

Recent impact of fire on high-altitude balsam fir forests in south-central Quebec1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1289-1305 ◽  
Author(s):  
Pierre-Luc Couillard ◽  
Serge Payette ◽  
Pierre Grondin
Keyword(s):  
High Altitude ◽  
Fire Regime ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Stand Age ◽  
Forest Types ◽  
Plant Composition ◽  
White Birch ◽  
South Central

The dynamics of high-altitude balsam fir ( Abies balsamea (L.) Mill.) forests is mainly driven by insect outbreaks and windthrows. However, very little work has been done on the role of fire on the development and maintenance of this ecosystem. In this study, we document the role of fire in the high-altitude balsam fir forests of the Réserve Faunique des Laurentides (RFL), southern Quebec. Sixteen sites were sampled among six different forest types described according to plant composition and fire evidence. At each site, the diameter structure was recorded and stand age was calculated based on tree-ring dating of individual trees and radiocarbon-dated surficial charcoal samples. Fire played a major role in the recent dynamics of high-altitude fir forests in the RFL. Over the last 250 years, nearly 50% of the study area burned during two fire conflagrations, i.e., around 1815 and in 1878. The fires triggered gradual changes in plant composition and forest structure, as shown by a succession of forest types ranging from white birch ( Betula papyrifera Marsh.) to spruce–fir types. Absence of surficial charcoal older than 300 years suggests that high-altitude forests of the RFL area were not subjected to a constant fire regime. It is possible that recent fires were caused by human activity.

Long-term Growth and Yield Response of Young Fir to Manual and Chemical Release from Shrub Competition

1983 ◽  
Vol 59 (4) ◽  
pp. 177-183 ◽  
Author(s):  
D. A. MacLean ◽  
M. G. Morgan
Keyword(s):  
Abies Balsamea ◽  
Control Plot ◽  
Growth And Yield ◽  
Yield Response ◽  
Betula Papyrifera ◽  
Growth Responses ◽  
White Birch ◽  
Individual Tree ◽  
Chemical Release

Long-term growth responses from manually and chemically releasing balsam fir (Abies balsamea (L.) Mill.) seedlings from shrub competition were examined on five 0.4-ha plots in northwestern New Brunswick. Manually releasing seedlings from mountain maple (Acer spicatum Lam.) competition by clearing a 1-m radius circle around each seedling in one plot resulted in increases of 64% for total fir volume, 36% for mean dbh, and 22% for mean height, in comparison with a control plot, 32 years later. Application of a 2,4-D — 2,4,5-T mixture to two plots resulted in 265 and 157% greater fir volume than the control plot 28 years later. Herbicide treatment dramatically changed the species composition of the treated plots, favoring fir and spruce (Picea sp.) over pin cherry (Prunus pensylvanica L.f.) and white birch (Betula papyrifera Marsh.), but had lesser effects on individual-tree growth rates.

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