The effects of feeding microsporidian (Nosema fumiferanae) spores to naturally infected spruce budworm (Choristoneura fumiferana)

1977 ◽  
Vol 55 (1) ◽  
pp. 249-250 ◽  
Author(s):  
G. G. Wilson
Keyword(s):  
Adverse Effect ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Adult Longevity ◽  
Pupal Mortality

Infection of spruce budworm, Choristoneura fumiferana, in nature by Nosema fumiferanae has an adverse effect on the host. Larval and pupal mortality are increased, while female pupal weights, adult longevity, and fecundity are significantly reduced by feeding additional microsporidian spores to naturally infected spruce budworm.

THE EFFECT OF A MICROSPORIDIAN PARASITE ON THE DEVELOPMENT, REPRODUCTION, AND MORTALITY OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.)

1958 ◽  
Vol 36 (4) ◽  
pp. 499-511 ◽  
Author(s):  
H. M. Thomson
Keyword(s):  
Initial Dose ◽  
Male Fertility ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Malpighian Tubules ◽  
Pupal Weight ◽  
Adult Longevity ◽  
Microsporidian Parasite ◽  
Pupal Development ◽  
First Instar

Infection of the spruce budworm, Choristoneura fumiferana (Clem.), by the microsporidian parasite Perezia fumiferanae Thorn, retards both larval and pupal development and reduces pupal weight, fecundity, and adult longevity. These effects are more pronounced among the female insects. There is no evidence that the parasite affects male fertility, mate choice, or the fertility of eggs produced. The parasite causes some mortality, most of which occurs before the fifth instar. Among larvae infected orally, mortality seems to be related to the size of the initial dose. Mortality occurs equally in both sexes. The development and survival of the first instar and overwintering second instar are not affected by the parasite. It is suggested that the parasite causes most of the observed results by reducing the insect's ability to assimilate its food. Mortality, however, is believed to be due to the destruction of the mid-gut or Malpighian tubules.

Interaction of Apanteles fumiferanae (Hymenoptera: Braconidae) and Nosema fumiferanae (Microsporidia) parasitizing spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae)

1987 ◽  
Vol 65 (8) ◽  
pp. 2047-2050 ◽  
Author(s):  
V. G. Nealis ◽  
S. M. Smith
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Dry Weight ◽  
Mass Rearing ◽  
Adult Longevity ◽  
Slight Reduction ◽  
Rate Of Development ◽  
Larval Female ◽  
The Relationship ◽  
Larval Parasites

The relationship between a braconid parasitoid, Apanteles fumiferanae, and a microsporidian pathogen, Nosema fumiferanae, two larval parasites frequently coincident in the spruce budworm, Choristoneura fumiferana, was examined in the laboratory. When Apanteles was reared in spruce budworm infected with high levels of Nosema (i.e., more than 20 × 106 spores/mg dry weight), there was a slight reduction in the within-host rate of development of larval female Apanteles, but survival, within-cocoon rate of development, cocoon weight, and adult longevity were not affected. There was no evidence that any stage of Apanteles was infected with spores of Nosema. A few adult female parasitoids were found to carry spores of Nosema on their integuments but it is unlikely that Apanteles is an important vector of the microsporidian. We conclude that these natural enemies of budworm do not interact significantly in their common host. The implications for population dynamics of the spruce budworm and mass rearing of Apanteles are discussed.

Detrimental effects of feeding Pleistophora schubergi (Microsporida) to spruce budworm (Choristoneura fumiferana) naturally infected with Nosema fumiferanae

1978 ◽  
Vol 56 (4) ◽  
pp. 578-580 ◽  
Author(s):  
G. G. Wilson
Keyword(s):  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Spruce Budworm ◽  
Adult Longevity

Spores of the microsporidian Pleistophora schubergi Zwölfer were fed to spruce budworm, Choristoneura fumiferana (Clem.), naturally infected with Nosema fumiferanae (Thorn.). Larval mortality increased while female pupal weights, adult longevity, and fecundity were significantly reduced by feeding P. schubergi spores. High spore concentrations (5 × 108 spores) and inoculation as second-instar larvae produced the most detrimental effects.

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.

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

2021 ◽  
Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien
Keyword(s):  
Boreal Forests ◽  
Large Scale ◽  
Choristoneura Fumiferana ◽  
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.

Weather and Outbreaks of the Spruce Budworm in the Province of Quebec from 1939 to 1956

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
The Past ◽  
Forest Regions ◽  
Tree Component ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.

GROUND RELEASES OF TRICHOGRAMMA MINUTUM RILEY (HYMENOPTERA: TRICHOGRAMMATIDAE) AGAINST THE SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE)

1987 ◽  
Vol 119 (3) ◽  
pp. 251-263 ◽  
Author(s):  
S.M. Smith ◽  
M. Hubbes ◽  
J.R. Carrow
Keyword(s):  
Optimal Strategy ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Egg Mass ◽  
Northern Ontario ◽  
Inundative Release ◽  
Egg Masses ◽  
Trichogramma Minutum ◽  
Spruce Stands ◽  
Natural Parasitism

AbstractDuring 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.

Prescribed Burning for Stand Conversion in Budworm-killed Balsam Fir: An Ontario Case History

1986 ◽  
Vol 62 (2) ◽  
pp. 96-100 ◽  
Author(s):  
D. J. McRae
Keyword(s):  
Fuel Consumption ◽  
Prescribed Burning ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Fire Spread ◽  
Fire Effects ◽  
Balsam Fir ◽  
Prescribed Burn ◽  
Stand Conversion

Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.

WHITE SPRUCE AND THE SPRUCE BUDWORM: DEFINING THE PHENOLOGICAL WINDOW OF SUSCEPTIBILITY

1997 ◽  
Vol 129 (2) ◽  
pp. 291-318 ◽  
Author(s):  
Robert K. Lawrence ◽  
William J. Mattson ◽  
Robert A. Haack
Keyword(s):  
Picea Glauca ◽  
High Performance ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
White Spruce ◽  
Shoot Elongation ◽  
Larval Survival ◽  
Strongly Correlated ◽  
Negative Effect ◽  
Foliar Traits

AbstractSynchrony of insect and host tree phenologies has often been suggested as an important factor influencing the susceptibility of white spruce, Picea glauca (Moench) Voss, and other hosts to the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). We evaluated this hypothesis by caging several cohorts of spruce budworm larvae on three white spruce populations at different phenological stages of the host trees, and then comparing budworm performance with host phenology and variation of 13 foliar traits. The beginning of the phenological window of susceptibility in white spruce occurs several weeks prior to budbreak, and the end of the window is sharply defined by the end of shoot growth. Performance was high for the earliest budworm cohorts that we tested. These larvae began feeding 3–4 weeks prior to budbreak and completed their larval development prior to the end of shoot elongation. Optimal synchrony occurred when emergence preceded budbreak by about 2 weeks. Larval survival was greater than 60% for individuals starting development 1–3 weeks prior to budbreak, but decreased to less than 10% for those starting development 2 or more weeks after budbreak and thus completing development after shoot elongation ceased. High performance by the budworm was most strongly correlated with high levels of foliar nitrogen, phosphorous, potassium, copper, sugars, and water and low levels of foliar calcium, phenolics, and toughness. These results suggest that advancing the usual phenological window of white spruce (i.e. advancing budbreak prior to larval emergence) or retarding budworm phenology can have a large negative effect on the spruce budworm’s population dynamics.

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