Natural Control Factors Affecting the Spruce Budworm in the Adirondacks During 1946–19481

Dowden, Philip B.; Carolin, V. M.; Dirks, C. O.

doi:10.1093/jee/43.6.774

Cited by 34 publications

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“…With the exception of a few studies on the taxonomy of E. cacoeciae and reports of its occurrence in nature (e.g., Dowden et al 1948Dowden et al , 1950Carolin and Coulter 1959;Torgersen 1969;Lindquist 1973;Miller andRenault 1976, 1981;Hanson 1982;Schauff 1985;Huber et al 1996), very little is known of the biology of E. cacoeciae and its role in the population dynamics of spruce budworm and its other hosts. In this paper, we report the results of field and laboratory experiments designed to elucidate various aspects of the biology of this little known parasitoid, including parasitism rates, oviposition behavior, age-specific and realized fecundity, size, development, and longevity.…”

Section: Introductionmentioning

confidence: 99%

RESISTANCE TO THE FLEA BEETLE PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN FALSE FLAX, CAMELINA SATIVA (BRASSICACEAE)

1998

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The Canadian Entomologist 130: 215 -229 (1998) We carried out a 2-year study to elucidate the biology of the gregarious, idiobiont ectoparasitoid Elachertus cacoeciae (Howard) by placing (implanting) laboratoryreared spruce budworm larvae [Choristoneura fumferana (Clemens)] on curreatyear balsam fir (Abies balsamea L.) shoots in the field, simulating low (endemic) densities of the budworm. Spring female E. cacoeciae attacked fourth-, fifth-, and sixth-instar budworm larvae, beginning near the predicted peak of the fourth instar and ending about 10-12 days after the predicted peak of the pupal stage of the wild budworm population. The mean (fSE) brood size of spring females was 2.9 f 0.3 E. cacoeciae pupae per host. The proportion of females increased during the season, with many broods consisting of 100% females late in the season. In 1994 and 1995, the mean proportion of females was 0.74 f 0.05 and 0.79 + 0.05, respectively. In the laboratory, development time from eggs to adults was approximately 20 days at 20.6OC. Adult males provided with honey water lived 43.6 f 3.2 days, whereas females provided with hosts and honey water lived 90.1 f 6.6 days.Spring females had a pre-oviposition period of 11.5 + 1.3 days, resulting in a generation time (egg to egg) of -31 days. The oviposition period lasted 76.3 f 7.7 days during which time spring females parasitized 19.2 f 1.9 hosts, and produced a clutch size of 4.9 f 0.4 eggs per host, for a lifetime fecundity of 96.8 f 14.7 eggs.The post-oviposition period was 18.5 + 3.7 days. Throughout their lifetime, spring females host fed only (host feeding without oviposition) on an additional 9.3 + 1.9hosts. Approximately 2% of pupae developing from spring females overwintered, whereas approximately 95% of pupae developing from summer females overwintered. Laboratory results for summer females suggest that they may be adapted to parasitizing alternate host(s) rather than spruce budworm.

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Section: Introductionmentioning

confidence: 99%

RESISTANCE TO THE FLEA BEETLE PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN FALSE FLAX, CAMELINA SATIVA (BRASSICACEAE)

1998

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“…Several workers (Kendeigh 1 94 7, Dowden et al 1948, Dowden and Carolin 1950, Graham 1967, Mattson 1974 have indicated that birds may restrict expansion of low-density budworm populations. In an earlier study, we hypothesized that forest-dwelling birds were effective in maintaining budworm populations at low densities (Crawford et al 1983).…”

Section: Introductionmentioning

confidence: 99%

Predation by Birds on Spruce Budworm Choristoneura Fumiferana: Functional, Numerical, and Total Responses

Crawford¹,

Jennings²

1989

Ecology

125

106

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This study examined the hypothesis that predation by forest birds restricts expansion of low-density populations of the spruce bud worm Choristoneura fumiferana (Lepidoptera: Tortricidae). Bird populations were censused in spruce-fir stands of low to moderate spruce budworm density in northern New Hampshire and western Maine. Diets were determined from stomach contents of collected birds. Bud worm population densities were estimated by sampling fourth-instar larvae and successfully emerged pupae (counted after moth emergence).Populations of spruce bud worms ranged from 80 x 10 3 to > 22 x 10 6 larvae/ha and from 0 to 1.2 x 10 6 pupae/ha. Birds ate spruce budworms throughout the daylight hours.Blackburnian Warblers consumed the most Choristoneura (X = 28 420 budworms/ha), followed by Cape May Warblers (X = 26 220 budworms/ha), and grading down to no consumption by some species.In plots where spruce budworm densities ranged from low to transitional, the entire bird community as well as specific groups of birds, i.e., overstory warblers and Goldencrowned Kinglets; sparrows, vireos, and juncos; and nuthatches, thrushes, and Purple Finches, showed significant functional responses to increasing budworm density. When transitional bud worm densities were eliminated from the analysis, only the warbler-kinglet group exhibited a significant functional response. Only two species, Canada Warbler and Golden-crowned Kinglet, showed numerical responses to increasing budworm numbers. The percentage of the budworm population consumed by birds decreased as budworm numbers increased. Birds consumed 84% of the larvae and pupae where budworm populations were low, 22% where budworm populations were intermediate between low and high density. Once fourth-instar larvae exceeded 10 6 individuals/hectare, bird predation was ineffectual. The hypothesis that birds can effectively limit budworm increase is compatible with three recent theories to explain budworm outbreaks.The forest stands we studied were dense, even-aged, with little understory. Numbers of birds potentially can be increased by modifying these stands through silvicultural means . Birds are capable of dampening the seriousness of spruce budworm infestations when habitats are suitable for supporting adequate populations of these effective predators.

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“…Rates of parasitism by T. minutum on spruce budworm are notoriously variable (Dowden et al, 1948;Dowden & Carolin, 1950;Jaynes & Drooz, 1952;Miller, 1953Miller, , 1963Neilson, 1963;Thomas, 1966;Houseweart et al, 1982). Much of the variability is likely to depend on the availability of alternate hosts (Miller, 1953(Miller, , 1963Neilson, 1963).…”

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Forest composition, host‐population density, and parasitism of spruce budworm Choristoneura fumiferana eggs by Trichogramma minutum

Quayle

Régnière

Cappuccino

et al. 2003

Entomologia Exp Applicata

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The frequency of egg parasitism in the spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae) by Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae) was recorded in several host populations during the rising phase of an outbreak in the Gatineau Valley (Quebec, Canada) in 1999 and 2000. Some of the observed spruce budworm populations were subjected to experimental aerial applications of Bacillus thuringiensis var. kurstaki during the course of the study. Untreated spruce budworm population densities at the onset of the study were directly related to stand composition (the proportion of non‐host basal area) but unrelated to plant species diversity. Much of the variation in budworm egg mass parasitism rates was accounted for (77.1% of total variance) by three variables: year, spruce budworm egg population density, and proportion of non‐host basal area in the stand. The exploitation of eggs within parasitised egg masses was related to year, B. thuringiensis treatment, egg mass size, and the proportion of egg masses parasitised in the host population (76.9% of variance). The yearly variation in parasitism rate was considerable, and was consistent with climatic conditions, namely heat accumulation and precipitation during the spruce budworm oviposition period. Parasitism by T. minutum on eggs of C. fumiferana was recorded in 16 additional sites in 2000, to confirm the general form of the inverse density dependence of parasitism. Observations recorded by Neilson in the Green River area of New Brunswick (Canada) between 1948 and 1957 are discussed in the context of the present analysis. These results indicate that parasitism by T. minutum may be more predictable than previously believed and may be an important and consistent source of mortality in the several years preceding an outbreak of C. fumiferana, especially in mixed‐wood stands and in warmer, drier portions of the spruce budworm's range.

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Natural Control Factors Affecting the Spruce Budworm in the Adirondacks During 1946–19481

Cited by 34 publications

References 0 publications

RESISTANCE TO THE FLEA BEETLE PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN FALSE FLAX, CAMELINA SATIVA (BRASSICACEAE)

RESISTANCE TO THE FLEA BEETLE PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN FALSE FLAX, CAMELINA SATIVA (BRASSICACEAE)

Predation by Birds on Spruce Budworm Choristoneura Fumiferana: Functional, Numerical, and Total Responses

Forest composition, host‐population density, and parasitism of spruce budworm Choristoneura fumiferana eggs by Trichogramma minutum

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