Desiccation resistance in pre-diapause, diapause and post-diapause larvae of Choristoneura fumiferana (Lepidoptera: Tortricidae)

2001 ◽  
Vol 91 (5) ◽  
pp. 321-326 ◽  
Author(s):  
É Bauce ◽  
E. Han
Keyword(s):  
Water Content ◽  
Freeze Drying ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Water Evaporation ◽  
Desiccation Resistance ◽  
First Instar ◽  
Access To Water ◽  
Almost All

AbstractDesiccation resistance was examined in pre-diapause, diapause and post-diapause larvae of the spruce budworm, Choristoneura fumiferana (Clemens), in terms of passive water evaporation under three desiccation conditions: freeze-drying, desiccant-drying at 2°C and desiccant-drying 18°C. Diapausing second instar larvae and post-diapause non-feeding second instar larvae showed strongest desiccation resistance: a significant amount of water was retained after repeated drying under desiccating conditions, while pre-diapause first instar larvae and post-diapause feeding instar larvae lost almost all their water content after one or two drying cycles. A hibernaculum covering had no effect on water evaporation. While dead larvae tended to lose significantly more water than their living counterparts, particularly among first instar larvae, such an impact much weaker among diapausing second instar larvae. Desiccation resistance was lost when post-diapause second instar larvae were allowed access to water while the level of desiccation resistance was maintained or enhanced when the larvae did not have access to water. These results are discussed the context of overwintering ecology of the species and possible mechanisms for the desiccation resistance are also discussed.

STUDIES ON DIPTEROUS PARASITES OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA.TORTRICIDAE): VI. PHOROCERA INCRASSATA SMITH (DIPTERA:TACHINIDAE)

1958 ◽  
Vol 36 (4) ◽  
pp. 453-462 ◽  
Author(s):  
H. C. Coppel
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Immature Stages ◽  
Eastern Canada ◽  
First Instar

Phorocera incrassala Smith, which was transferred from Western to Eastern Canada for release against the spruce budworm, Choristoneura fumiferana (Clem.), deposits microtype eggs on leaves, which are later ingested by the host. Eggs hatch immediately after ingestion, but the parasite does not develop beyond the first instar until the host pupates. The larva then develops rapidly, matures in 10 days, and forms its puparium within the host pupal case. The adult emerges in 12 to 14 days. No information is available on the overwintering habits. Among the important characters for identifying the immature stages of P. incrassala are the buccopharyngeal apparatus and the anterior and posterior spiracles.

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.

SUSCEPTIBILITY OF EARLY INSTARS OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) TO HETERORHABDITIS HELIOTHIDIS (NEMATODA: RHABDITIDAE)

1984 ◽  
Vol 116 (2) ◽  
pp. 285-287
Author(s):  
Jean R. Finney ◽  
Gordon F. Bennett
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Control Agent ◽  
Balsam Fir ◽  
Larval Instars ◽  
First Instar ◽  
Cryptic Habitats ◽  
Chemical Pesticides ◽  
Third Instar Larvae

Finney et al. (1982) reported on the susceptibility of the 4th to 6th larval instars and pupae of Choristoneura fumiferana (Clemens) to Heterorhabditis heliothidis (Khan, Brooks and Hirschmann). This report describes the susceptibility of the first three larval instars to the nematode. First-instar larvae search for suitable sites where they spin hibernacula in which they molt and overwinter as second-instar larvae. Most third-instar larvae burrow within the balsam fir buds. All these stages occupy cryptic habitats to which delivery of chemical pesticides is a problem. Rhabditid nematodes, which can actively seek out a target insect, may prove a more useful control agent under these circumstances.

THE OCCURRENCE AND NATURE OF DIAPAUSE-FREE DEVELOPMENT IN THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE)

1957 ◽  
Vol 35 (4) ◽  
pp. 549-572 ◽  
Author(s):  
George T. Harvey
Keyword(s):  
Environmental Conditions ◽  
Behavior Pattern ◽  
Choristoneura Fumiferana ◽  
Continuous Light ◽  
Spruce Budworm ◽  
Light Treatment ◽  
Complex Behavior ◽  
Eastern Canada ◽  
First Instar ◽  
Free Development

Spruce budworm populations in Eastern Canada are effectively univoltine. After hatching, the larva follows a complex behavior pattern that leads to the building of a hibernaculum in which it molts and spends the winter months without feeding. This pattern seems to be independent of environmental conditions, except as they affect the rate at which the component events occur, and, in the absence of any evidence to the contrary, must be considered as inherent.Laboratory studies have shown that in 62% of the families produced by matings of field-collected individuals at least one larva can develop without diapause if subjected to long photoperiods (at 71° F.); on the average 3 to 4% of the second-instar larvae in such progenies can forego diapause. Selection over six generations yielded a strain that, if subjected to continuous light in the laboratory, is virtually free from diapause. This stock has been reared for a further six generations and still retains this photoperiod dependence. Behavior is usually normal during hibernaculum construction and molting, but then the larvae vacate their shelters, feed readily, and develop without any delay. No associated differences have yet been found between non-diapause (N-D) and normal (D) insects. The ability to develop without diapause is apparently determined by multiple genes; it is not sex-linked but may be to some extent sex-controlled.Diapause-free development in this strain results only when first-instar larvae are exposed to a photoperiod of at least 15 hours, shorter times resulting in almost universal diapause and longer times giving a progressively greater proportion of N-D insects, approaching 100% in continuous light. This response is reduced by lower temperatures. Potential N-D insects deprived of a light-treatment behave as normal D insects; under appropriate conditions of light their progeny in turn develop without diapause.

Does nutrition-related stress carry over to spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae) progeny?

2002 ◽  
Vol 92 (2) ◽  
pp. 101-108 ◽  
Author(s):  
N. Carisey ◽  
É. Bauce
Keyword(s):  
Choristoneura Fumiferana ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Pupal Weight ◽  
Total Soluble Sugar ◽  
First Instar ◽  
Parental Nutrition ◽  
Biological Performance

AbstractThree different patterns of feeding of sixth-instar spruce budworm, Choristoneura fumiferana Clemens were simulated in the laboratory. Larvae were fed artificial diets whose nitrogen and total soluble sugar contents varied according to levels similar to those found in three types of balsam fir, Abies balsamea (L.) Miller foliage (current-year foliage from middle and lower crown sections and one-year-old foliage). The biological performance of offspring was studied according to the nutrition of their parents. Although food quality had no impact on pupal weight of female parents and individual mean egg weight, progeny fitness was influenced by parental nutrition. Old foliage simulated diet, poor in nitrogen, clearly affected the early larval development of progeny, especially the percent of egg hatch and first-instar survival. Lower crown current-year foliage simulated diet, with low total soluble sugar content, reduced the first-instar survival of the progeny. However, the selective pressure exerted by low food qualities on the parental generation and on the early stages of their progenies resulted in C. fumiferana populations having higher tolerance to starvation and higher survival after the diapause period. These results highlighted the potentially direct and indirect effects of C. fumiferana parental nutrition on the next generation. The patterns of feeding of parental generations would appear to affect the quality and size of subsequent populations through several selections on the different life-history stages of both generations.

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.

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