Aerial Application of Bt Against Spruce Budworm: 1982 Bt Cooperative Field Tests—Combined Summary1

1984 ◽  
Vol 77 (4) ◽  
pp. 999-1003 ◽  
Author(s):  
F. B. Lewis ◽  
G. S. Walton ◽  
J. B. Dimond ◽  
O. N. Morris ◽  
B. Parker ◽  
...  
1978 ◽  
Vol 54 (6) ◽  
pp. 309-312 ◽  
Author(s):  
W.A. Smirnoff

Action of Bacillus thuringiensis (B.t.) on spruce budworm, Choristoneura fumiferana Clem., was found to be attributable to septicemia with some enterotoxicosis. Development of a compact economical B.t. formulation, with addition of the enzyme chitinase, increased its efficiency by accelerating larval mortality. Between 1971 and 1975 field tests were conducted in balsam fir stands with different levels of insect density to select the best formulation and methods of application and to identify the major influencing environmental variables. Variability in the results prior to 1975 is attributable to difficulties with calibration of spray systems. With accurate calibration in 1976 and 1977, good results in terms of larval mortality and foliage protection were obtained, thus confirming the value of B.t. for control of spruce budworm.


1981 ◽  
Vol 113 (9) ◽  
pp. 819-825 ◽  
Author(s):  
Charles E. Richmond

AbstractA new spray application system which mimics the spray deposit of aerial applications of chemical insecticides was developed and tested using acephate at the rate of 60 g a.i./L (U.S. Environmental Protection Act registered dosage) on small Douglas-fir and subalpine fir trees infested with western spruce budworm. The system successfully duplicated aerial application by causing a budworm population reduction equivalent to previous aerial tests having analogous insecticide deposit characteristics. Using the system, preliminary information was gained on the effectiveness of sulprofos and thiodicarb. When delivered at a rate of 4.1 L/ha, sulprofos caused a budworm population reduction of 86.2% at 22.4 g a.i./L and thiodicarb caused a reduction of 98% at 45 g a.i./L.


1978 ◽  
Vol 110 (6) ◽  
pp. 561-567 ◽  
Author(s):  
B. Sechser ◽  
I. W. Varty

AbstractAirplane application of the insect growth regulator CGA 13353, a juvenile hormone mimic used experimentally against spruce budworm, Choristoneura fumiferana (Clem.), did not drastically reduce percentage parasitism in field samples of that host, but there was some evidence of susceptibility. Exploratory sampling of maple defoliators suggested that one species and its parasitoids suffered some mortality, but another species and its parasitoids did not. The treatment did not influence the viability of ant colonies.


2000 ◽  
Vol 132 (4) ◽  
pp. 505-518 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Carl Nystrom ◽  
John Dedes ◽  
Vern Seligy

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.


1961 ◽  
Vol 37 (3) ◽  
pp. 203-210 ◽  
Author(s):  
J. R. Blais

The aerial application of insecticides against spruce budworm outbreaks is now a common practice. The measure had always been applied in outbreaks covering more or less extensive areas until 1960 when an opportunity was provided of spraying a small incipient infestation in the Lower St. Lawrence region of the Province of Quebec. It was hoped that early treatment might suppress the infestation and prevent its spread. Although the operation was successful in greatly reducing insect numbers in the area treated, it failed to arrest the infestation. Wind dispersal of first- and second-instar larvae prior to spray application resulted in the spread of the infestation beyond the area delimited for treatment. Also, the warm and dry weather in the spring of 1960, and the abundance of staminate flowers on the balsam fir and spruce trees greatly favoured larval survival. The aerial application of insecticides as a method of suppressing incipient spruce budworm outbreaks is discussed in the light of these results.


1977 ◽  
Vol 109 (6) ◽  
pp. 875-878 ◽  
Author(s):  
G. E. Daterman ◽  
R. G. Robbins ◽  
T. D. Eichlin ◽  
J. Pierce

AbstractField tests of (E)-11-tetradecenal and (E)-11-tetradecenyl acetate, the respective sex attractants for western spruce budworm, Choristoneura occidentalis Freeman and the Modoc budworm, C. viridis Freeman, revealed that these compounds attract several other forest Lepidoptera. The acetate attracted a total of 14 species representing seven families, and the aldehyde accounted for nine species representing four families. This interspecific attraction could influence budworm trapping efficiency and interpretation of results, because of the abundance of other responding species and the fact that two of the species resemble Choristoneura adults in appearance.


1963 ◽  
Vol 95 (8) ◽  
pp. 821-827 ◽  
Author(s):  
J. R. Blais

AbstractAn attempt was made to suppress an incipient spruce budworm outbreak in the Lower St. Lawrence region of Quebec through the aerial application of DDT. Operations began in 1960 and continued in 1961 and 1962 when they finally met with success. Failure to achieve success earlier was due partly to the exceptionally favourable survival conditions for the insect in 1960, and partly to the inadvertent omission of a small infested area from the program in 1961. The operations greatly reduced spruce budworm populations each year in the outbreak area, while the action of natural control factors, including parasites and predators increased. The collapse of the outbreak was the result of the combined effects of the chemical treatments and of natural control factors.


1979 ◽  
Vol 111 (7) ◽  
pp. 847-850 ◽  
Author(s):  
Arthur Retnakaran

AbstractIn laboratory tests on the spruce budworm, Choristoneura fumiferana (Clemens), EL-494®, a new moult-inhibiting insect growth regulator, was found to be more active than Dimilin. The EC50 determined by diet tests was 0.205 ppm for the 3rd, 0.249 for the 4th, 0.287 for the 5th, and 0.486 for the 6th instars. Stadial sensitivity was not detected.In greenhouse tests this compound was found to be resistant to leaching and UV-degradation; the compound remained active on spruce foliage for at least 15 days. In preliminary field tests EL-494 showed good potential as a control agent.


1976 ◽  
Vol 52 (2) ◽  
pp. 57-60 ◽  
Author(s):  
J. R. Blais

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.


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