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.

3.5 SUPPRESSION OF SPRUCE BUDWORM POPULATIONS BY TRICHOGRAMMA MINUTUM RILEY, 1982–1986

1990 ◽  
Vol 122 (S153) ◽  
pp. 56-81 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace ◽  
G. Howse ◽  
J. Meating
Keyword(s):  
Choristoneura Fumiferana ◽  
Host Density ◽  
Spruce Budworm ◽  
Mass Rearing ◽  
Egg Parasitoid ◽  
Curvilinear Relationship ◽  
Egg Masses ◽  
Trichogramma Minutum ◽  
Egg Parasitism ◽  
Release Timing

AbstractThe ability of the egg parasitoid, Trichogramma minutum Riley, to suppress outbreak populations of the spruce budworm, Choristoneura fumiferana (Clemens), was studied annually near Hearst, Ont., from 1982 through 1986. Timing of broadcast parasitoid-releases was linked to spruce budworm moth emergence and oviposition. These phenological relationships were predicted from a regression based on larval development at least 2 weeks before expected emergence; this allowed sufficient time to regulate (program) parasitoid emergence during mass-rearing. Emergence of caged spruce budworm adults was used to monitor moth eclosion in the field. Pheromone traps provided daily information on the activity of male moths and helped to synchronize the parasitoid releases with spruce budworm oviposition. Information on parasitoid activity was obtained from sentinel (laboratory-reared) and naturally occurring spruce budworm egg masses. A curvilinear relationship between the rate of parasitoid release and parasitism of sentinel egg masses was developed. Two parasitoid releases, 1 week apart, early in the oviposition period of spruce budworm, significantly increased parasitism of host eggs by 14–83% and reduced larval populations correspondingly from 42 to 82%. Single releases were less effective and increased parasitism by 0.3–52% (single ground release, 1986). Two parasitoid releases, combined with a spring application of Bacillus thuringiensis Berliner to larval populations, was the most effective strategy and resulted in 83% egg parasitism and 93% larval reduction. Release rates greater than 12–16 × 106 ♀ ♀ T. minutum per hectare were not warranted based on impact and costs. The effects of release timing, weather, host density, and parasitoid quality on the future successful use of T. minutum are discussed.

A Cartographic History of Spruce Budworm Outbreaks and Aerial Forest Spraying in the Atlantic Region of North America, 1949–1959

1961 ◽  
Vol 93 (5) ◽  
pp. 360-379 ◽  
Author(s):  
F. E. Webb ◽  
J. R. Blais ◽  
R. W. Nash
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Maritime Provinces ◽  
Atlantic Region ◽  
Northern Ontario ◽  
Past Half Century ◽  
History Of ◽  
Canadian Provinces ◽  
Past Half ◽  
St Lawrence River

The spruce budworm (Choristoneura fumiferana (Clem.)) is a forest pest in all Canadian Provinces and Territories, and in the northeastern, midwest, and northwestern Unired States. It is by iar the most destructive insect affeiting the extensive balsam fir-spruce forest types in Ontario, Quebec, the Maritime Provinces, and Maine. Outbreaks of varying extent have been reported from these regions almost every year for the past half-century (deGryse, 1947). Periods in which outbreaks were particularly severe and widespread occurred from about 1909 to 1920 and in the 1940's and 1950's. In both periods, outbreaks showed a tendency to shift from west to east, intensifying first in parts of northern Ontario and Quebec and dying out in the Atlantic region south of the St. Lawrence River.

Predicting Tree Mortality Induced by Spruce Budworm: A Discussion

1983 ◽  
Vol 59 (6) ◽  
pp. 294-297 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Regional Differences ◽  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Reliable Prediction ◽  
Spruce Stands ◽  
Term Management ◽  
Forest Managers

Forest managers have expressed the need for guidelines that would predict, up to 5 years, the annual spruce budworm damage on a stand basis. Reasons why reliable prediction is generally not possible are discussed. It is suggested that long-term management programs, that would take into consideration periodic losses resulting from recurring budworm outbreaks and that would be based on regional differences in the vulnerability of fir-spruce stands, should be implemented. Key words: Spruce budworm, Choristoneura fumiferana; forest management; tree mortality; defoliation; stand vulnerability, balsam fir, Abies balsamea.

scholarly journals Vulnerability of Conifer Regeneration to Spruce Budworm Outbreaks in the Eastern Canadian Boreal Forest

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin
Keyword(s):  
Boreal Forests ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Insect Outbreaks ◽  
Spruce Stands ◽  
Canadian Boreal Forest

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.

PINE SISKIN PREYS ON EGG MASSES OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1983 ◽  
Vol 115 (4) ◽  
pp. 439-440
Author(s):  
Daniel T. Jennings ◽  
Hewlette S. Crawford
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Life Stages ◽  
Egg Masses

During preoutbreak periods before spruce budworm, Choristoneura fumiferana (Clemens), populations reach epidemic levels, birds can play an important role in regulating budworm abundance (Gage and Miller 1978). All life stages of the spruce budworm are subject to predation by birds, but documentation of predation on budworm eggs is sparse (Hope 1945).

A METHOD FOR SEPARATING AND SURFACE STERILIZING THE EGGS OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1971 ◽  
Vol 103 (5) ◽  
pp. 712-716 ◽  
Author(s):  
Arthur Retnakaran ◽  
John French
Keyword(s):  
Filter Paper ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Petri Dish ◽  
Distilled Water ◽  
Simple Method ◽  
Egg Masses ◽  
Sterile Filter

AbstractA simple method for separating and surface sterilizing spruce budworm eggs is described. The egg masses are incubated with constant agitation in a 1% solution of NaOH for 10 minutes at 35 °C. The separated eggs are rinsed serially in distilled water, 1% bovine albumen solution, and 70% ethanol, and placed on a moist, sterile filter paper in a petri dish. When surface sterilized eggs are not required the 70% ethanol wash can be omitted.

SIZE DIFFERENCES OF LABORATORY REARED AND WILD POPULATIONS OF TRICHOGRAMMA MINUTUM (HYMENOPTERA: TRICHOGRAMMATIDAE)

1982 ◽  
Vol 114 (8) ◽  
pp. 693-698 ◽  
Author(s):  
Susan G. Southard ◽  
Mark W. Houseweart ◽  
Daniel T. Jennings ◽  
William A. Halteman
Keyword(s):  
First Generation ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Head Width ◽  
Wild Populations ◽  
Body Dimensions ◽  
Female Parasitoid ◽  
Trichogramma Minutum ◽  
Three Body ◽  
Large Host

AbstractThree body dimensions (body length, head width, and abdomen width) were used to determine size differences between laboratory-reared and wild populations of Trichogramma minutum Riley. Six separate groups of T. minutum were measured: three groups were from Sitotroga cerealella (Olivier) eggs, two from spruce budworm Choristoneura fumiferana (Clemens) eggs, and one from wild populations of spruce budworm.Female T. minutum from spruce budworm (large host) eggs were significantly larger for all body dimensions than T. minutum from S. cerealella (small host) eggs. Male T. minutum from field-collected spruce budworm eggs were significantly larger for all body dimensions than T. minutum reared for more than one generation in S. cerealella eggs.A significant reduction in female parasitoid size was observed during the initial generations of T. minutum reared in the smaller host (S. cerealella). However, this size reduction was not permanent. Following numerous generations in the S. cerealella host eggs, a significant increase in female parasitoid size was noted within the first generation of T. minutum reared in the spruce budworm host eggs.

FIELD RELEASES OF TRICHOGRAMMA MINUTUM (HYMENOPTERA: TRICHOGRAMMATIDAE) FOR SUPPRESSION OF EPIDEMIC SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), EGG POPULATIONS IN MAINE

1984 ◽  
Vol 116 (10) ◽  
pp. 1357-1366 ◽  
Author(s):  
Mark W. Houseweart ◽  
Daniel T. Jennings ◽  
Robert K. Lawrence
Keyword(s):  
Point Source ◽  
Choristoneura Fumiferana ◽  
Single Point ◽  
Spruce Budworm ◽  
Point Sources ◽  
Slight Improvement ◽  
Parasitism Rates ◽  
Trichogramma Minutum ◽  
Multiple Releases ◽  
Better Than

AbstractTrichogramma minutum Riley was released in the field for suppression of epidemic spruce budworm, Choristoneura fumiferana (Clemens), egg populations in Maine from 1977 to 1981. Commercially reared California-strain T. minutum were released from the ground at single-point sources in 1977. In 1978, using 4-point-source releases, we found that the native Maine-strain performed better than the California strain. In 1979, broadcast and multiple releases from the ground gave slight improvement in parasitism over 4-point releases. In 1981, three closely timed, aerially broadcast releases from a helicopter yielded increases in parasitism rates significantly higher than those in control plots, but not sufficient to suppress epidemic spruce budworm populations. Important variables and suggestions for future aerial releases are discussed.

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