Lethal and Sublethal Effects of Single and Double Applications of Bacillus thuringiensis Variety kurstaki on Spruce Budworm (Lepidoptera: Tortricidae) Larvae

2003 ◽  
Vol 96 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Gaétan Moreau ◽  
Éric Bauce
Keyword(s):  
Bacillus Thuringiensis ◽  
Sublethal Effects ◽  
Spruce Budworm

Sublethal effects of Bacillus thuringiensis on the spruce budworm, Choristoneura fumiferana

1997 ◽  
Vol 83 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Anita Pedersen ◽  
John Dedes ◽  
Debbie Gauthier ◽  
Kees Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Sublethal Effects ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm

LONG TERM STUDY OF THE EFFECTIVENESS OF AERIAL APPLICATION OF BACILLUS THURINGIENSIS – ACEPHATE COMBINATIONS AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Population Densities ◽  
Long Term Study

AbstractBacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

EFFECT OF TEMPERATURE ON THE PATHOGENESIS OF BACILLUS THURINGIENSIS BERLINER IN LARVAE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEM. (LEPIDOPTERA: TORTRICIDAE)

1994 ◽  
Vol 126 (4) ◽  
pp. 1061-1065 ◽  
Author(s):  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacterial Growth ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Effect Of Temperature ◽  
Vegetative Cells ◽  
Time Required ◽  
Peak Abundance

AbstractThe relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.

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