DIAPAUSE DEVELOPMENT OF SPRUCE BUDWORM LARVAE, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE), AT TEMPERATURES FAVOURING POST-DIAPAUSE DEVELOPMENT

1996 ◽  
Vol 128 (1) ◽  
pp. 167-169 ◽  
Author(s):  
Er-Ning Han ◽  
Eric Bauce
Keyword(s):  
Cold Storage ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Diapause Development

Requirements for diapause development of larvae of Choristoneura fumiferana have been generally believed to be met by temperatures of 2°C or below for a period ranging from 14 to 20 weeks (see review by Sanders 1991), whereas those favourable for post-diapause development were shown to be above 11°C (Régnière 1990). However, we noticed that a large number of larvae completed diapause after 10 weeks at 18°C without any cold storage. The following experiment was carried out to confirm this result.

Effects of diapause duration on postdiapause performance of spruce budworm (Lepidoptera: Tortricidae) during mass rearing on artificial diet

2007 ◽  
Vol 139 (6) ◽  
pp. 834-840 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Peter Ebling ◽  
John Dedes ◽  
Doug Pitt
Keyword(s):  
Cold Storage ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Mass Rearing ◽  
Storage Duration ◽  
Performance Variables ◽  
Late Instar ◽  
Neonate Larvae ◽  
Pupal Mass ◽  
Diapause Duration

AbstractThe spruce budworm, Choristoneura fumiferana (Clem.), has an obligatory winter dormancy period that lasts up to 10 months in the field. In the Great Lakes Forestry Centre rearing facility, neonate larvae spin hibernacula in cheesecloth, which is then stored at 2 °C for between 20 and 30 weeks. Although dormancy survival and synchrony of postemergence development are highest when larvae are stored in the cold for 16–35 weeks, it is not known how cold-storage duration affects spruce budworm performance once diapause has been completed. We exposed approximately 9250 second-instar larvae (belonging to three rearing cohorts) to 2 °C for 16, 19, 22, 25, 28, 31, 34, or 37 weeks and monitored various postdiapause performance variables. Increasing cold storage from 16 to 25 weeks or more resulted in small (approximately 10%) increases in dormancy survival and larval development rates (from second instar to pupation), a larger (up to 23%) increase in pupal mass and realized fecundity (number of eggs laid per female), and an increase of at least 25% in late-instar survival (from fifth instar to pupation). The only variable that was negatively affected was the pupal survival, but the decrease was relatively small. Therefore, storing diapausing larvae for at least 25 weeks optimizes postdiapause performance variables that are important for mass-rearing efficiency.

OVERWINTERING MORTALITY OF SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE), POPULATIONS UNDER FIELD CONDITIONS

1998 ◽  
Vol 130 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Jacques Régnière ◽  
Pierre Duval
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Male Flower ◽  
Late Summer ◽  
Spruce Budworm ◽  
Weather Conditions ◽  
Overwintering Mortality ◽  
Highly Correlated ◽  
Diapause Development ◽  
Overwintering Survival

AbstractOverwintering mortality in the spruce budworm, Choristoneura fumiferana (Clem.), was measured between 1983 and 1990 in several natural stands of balsam fir, Abies balsamea (L.), in Quebec and Ontario. Overwintering losses (disappearance of larvae) averaged 25.2%, occurred mostly in late summer and early fall, and were probably caused by, in large part, failure to spin a hibernaculum, diapause-free development, and invertebrate predation. An average of 24.1% of larvae were found dead in the hibernaculum. This mortality also occurred early in diapause and during post-diapause development, and overwintering mortality did not vary much from year to year. We conclude that overwintering mortality does not result from adverse winter weather conditions or from gradual loss of hibernacula. Overall overwintering mortality from the loss of hibernating larvae plus death within the hibernaculum averaged 43.2% and was not related to infection with the microsporidian Nosema fumiferanae (Thomson). We observed no influence of position in the tree crown on overwintering survival. There was a 40% decrease in overwintering survival among larvae from eggs laid very late in a female’s oviposition sequence. Survival within the hibernaculum on shoots of A. balsamea bearing different types of spinning substrates varied considerably, and was highly correlated with larval spinning preferences. Shoots bearing lichen mats, rough bark, male flower scars, or 1-year-old annular scales were most suitable, whereas shoots bearing annular scales older than 1 year or smooth bark were least suitable. The efficiency of the NaOH extraction technique to recover overwintering spruce budworm larvae was found to be highly variable, and to depend on population density, shoot type, and the proportion of live larvae on the branches.

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.

Sign in / Sign up

Export Citation Format

Share Document