The Effect of a Microsporidian Parasite of the Spruce Budworm, Choristoneura fumiferana (Clem.), on Two Internal Hymenopterous Parasites

1958 ◽  
Vol 90 (11) ◽  
pp. 694-696 ◽  
Author(s):  
H. M. Thomson
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Microsporidian Parasite

Apanteles fumiferanae Vier. and Glylpta fumiferanae (Vier.) are two well known hymenopterous parasites of the spruce budworm in Canada. While studying a microsporidian disease of the budworm caused by Perezia fumiferanae Thom. (Thomson, 1955) it was observed that occasionally the microsporidian and one of the hymenopterous parasites occurred together in the same host. This paper is a report of a study of the effect of the microsporidian on the hymenopterous parasites.

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.

A dosing technique and the effects of sub-lethal doses of Nosema fumiferanae (Microsporida) on its host the spruce budworm, Choristoneura fumiferana

Parasitology ◽  
1983 ◽  
Vol 87 (3) ◽  
pp. 371-376 ◽  
Author(s):  
G. G. Wilson
Keyword(s):  
Adult Female ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Spore Concentration ◽  
Microsporidian Parasite ◽  
Male And Female ◽  
Female Longevity ◽  
Living Adult ◽  
Lethal Doses ◽  
Significant Mortality

SummaryVarious dosages of the microsporidian parasite, Nosema fumiferanae were fed to 12-day-old larvae of Choristoneura fumiferana using a previously undescribed bioassay capsule. A spore dose of 3 × 104 resulted in 92% infection and a significant reduction in pupal weights, adult female longevity and a mean spore concentration of 1·5 × 107/living adult. Significant mortality (68%, combined larvae and pupae) did not occur until larvae ingested 3 × 107 spores; this dose produced a mean of 1·8 × 107 spores in dead larvae and 3·6 × 107 and 4·6 × 107 spores in dead male and female pupae respectively.

SOME ASPECTS OF THE EPIDEMIOLOGY OF A MIGROSPORIDIAN PARASITE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.)

1958 ◽  
Vol 36 (3) ◽  
pp. 309-316 ◽  
Author(s):  
H. M. Thomson
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Single Species ◽  
Microsporidian Parasite ◽  
Oral Ingestion ◽  
Infected Female ◽  
Larval Instars ◽  
Congenital Transmission ◽  
Host Generation

Limited tests indicate that the microsporidian parasite Perezia fumiferanae is restricted to insect hosts of the genus Choristoneura and for practical purposes to the single species Choristoneura fumiferana (Clem.). Frozen spores of this parasite were found to be infectious longer than those kept under other conditions but no spores were infectious after 6 months' storage. There are two distinct methods of infection, oral and congenital. Immature eggs within infected female insects are infected by schizonts which develop into spores after the eggs are laid. All infected females, regardless of the degree of infection, transmit the parasite to their offspring, and for practical purposes all the progeny of such females are infected. Offspring of heavily infected females appear to contain more spores than those of lightly infected females. Infected males are sometimes capable of transmitting the parasite to a portion of their offspring. Congenital transmission is responsible for the passage of the parasite from host generation to generation. Increase in the incidence of the parasite occurs by oral ingestion of spores but the habits of the host larvae restrict most transmission to the late larval instars.

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.

FACTORS AFFECTING ADULT EMERGENCE AND MATING BEHAVIOR OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1975 ◽  
Vol 107 (9) ◽  
pp. 967-977 ◽  
Author(s):  
C. J. Sanders
Keyword(s):  
Field Experiments ◽  
Choristoneura Fumiferana ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Field Conditions ◽  
Continuous Illumination ◽  
Degree Days ◽  
Factors Affecting ◽  
Eastern Spruce Budworm ◽  
Duration Of Copulation

AbstractLaboratory and field experiments indicate that the female spruce budworm (Choristoneura fumiferana (Clem.)) pupal stadium requires approximately 122C degree-days above a threshold of 7.2 °C (45°F), the male 124. Emergence time on any given day depends on temperature but is independent of photoperiod. Under field conditions male and female budworm mate only once per 24-h period. In the laboratory under continuous illumination females mate repeatedly and males readily mate a second time within a few hours, but the duration of the second copulation is abnormally long. The probability of multiple matings under field conditions is reduced by the restricted period of sexual activity coupled with the duration of copulation and the lower competitiveness of mated insects. Antennae are essential to the male for successful copulation.

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