Can Bacillus Thuringiensis Replace Chemical Insecticides in the Control of Spruce Budworm?

1976 ◽  
Vol 52 (2) ◽  
pp. 57-60 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Bacillus Thuringiensis ◽  
Chemical Compounds ◽  
Spruce Budworm ◽  
Aerial Application ◽  
Forest Environment ◽  
Great Caution ◽  
Microbial Insecticide ◽  
Effective Reduction ◽  
Chemical Spray ◽  
Citizen Groups

Recent demands by citizen groups calling for replacement of chemical insecticides by Bacillus thuringiensis (B.t.), a microbial insecticide, for the control of spruce budworm have received considerable publicity. Effects of chemical spray operations on the forest environment are discussed, and progress made to date with trial applications of B.t. against spruce budworm is reported. Although great caution should be exercised in the aerial application of insecticides, there is no evidence that these chemical compounds at conventional dosages cause serious damage to the forest environment. Although a desirable substitute for chemicals, B.t. still presents many drawbacks and requires further experimentation before it can be recommended as an economic alternative for effective reduction of damage by spruce budworm.

MORTALITY, FEEDING INHIBITION, AND RECOVERY OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) LARVAE FOLLOWING AERIAL APPLICATION OF A HIGH-POTENCY FORMULATION OF BACILLUS THURINGIENSIS SUBSP. KURSTAKI

2000 ◽  
Vol 132 (4) ◽  
pp. 505-518 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Carl Nystrom ◽  
John Dedes ◽  
Vern Seligy
Keyword(s):  
Bacillus Thuringiensis ◽  
Spray Deposition ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Limiting Factor ◽  
Larval Feeding ◽  
Spray Application ◽  
Aerial Application ◽  
Feeding Inhibition

AbstractA larval population of spruce budworm, Choristoneura fumiferana (Clemens), was monitored for 5 d following aerial application of a commercial formulation of Bacillus thuringiensis Berliner subsp. kurstaki to investigate dose acquisition and expression (larval mortality, recovery, feeding, and growth) in relation to spray deposition and persistence of spray deposits. The main objective was to test if previous laboratory observations on how B. thuringiensis affects feeding and dose ingestion by spruce budworm larvae hold true under field conditions. About 40% of the treated population ingested a lethal dose within 1 d after spray application. Lethally dosed larvae died without further feeding upon transfer from treated foliage to (untreated) artificial diet. Resumption of feeding by larvae that survived the treatment was delayed relative to larvae from the control population during 3 d following spray application; during that time, normal feeding activity and larval weight gain were suppressed. Inhibited feeding by survivors appeared to prevent further dose uptake because the proportion of lethally dosed larvae in daily collections did not increase despite significant residual spray deposits in budworm feeding sites. Restoration of "normal" recovery times by the fourth day coincided with a 65–85% reduction in persistence of the pathogen on the foliage and did not result in further lethal dose acquisition, as treatment-induced mortality dropped to about 20% on the 4th and 5th days. The observations are consistent with previous laboratory observations of how B. thuringiensis affects larval feeding and with the hypothesis that feeding inhibition may be a limiting factor in the acquisition of a lethal dose.

EFFECTS OF NUCLEAR POLYHEDROSIS VIRUS AND BACILLUS THURINGIENSIS ON WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) 1 AND 2 YEARS AFTER AERIAL APPLICATION

1982 ◽  
Vol 114 (3) ◽  
pp. 281-282 ◽  
Author(s):  
R. F. Shepherd ◽  
T. G. Gray ◽  
J. C. Cunningham
Keyword(s):  
Bacillus Thuringiensis ◽  
Nuclear Polyhedrosis Virus ◽  
Spruce Budworm ◽  
Western Spruce Budworm ◽  
Aerial Application ◽  
Insect Populations ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis ◽  
The Impact ◽  
Selection Of

An understanding of all environmental effects resulting from control actions is important in the selection of a method of managing insect populations. Effects may extend beyond the year of treatment and can modify management decisions. In 1978, a nuclear polyhedrosis virus (NPV) and Bacillus thuringiensis Berliner (B.t.) were tested as aerial spray applications against the western spruce budworm, Choristoneura occidentalis Freeman, on Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, near Cache Creek, British Columbia. The impact on population densities and on the incidence of NPV was measured in the treated and non-treated areas for 2 vears following the year of application, and is reported here.

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.

Distribution of Toxin Genes and Enterotoxins in Bacillus thuringiensis Isolated from Microbial Insecticide Products

2015 ◽  
Vol 25 (12) ◽  
pp. 2043-2048 ◽  
Author(s):  
Seung-Hak Cho ◽  
Suk-Ho Kang ◽  
Yea-Eun Lee ◽  
Sung-Jo Kim ◽  
Young-Bin Yoo ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Toxin Genes ◽  
Microbial Insecticide
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