FACTORS AFFECTING CATCH IN PHEROMONE TRAPS FOR MONITORING THE WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN

1990 ◽  
Vol 122 (6) ◽  
pp. 1119-1130 ◽  
Author(s):  
J.D. Sweeney ◽  
J.A. McLean ◽  
R.F. Shepherd

AbstractThe effects of trap design, lure concentration, lure age, and trap maintenance on the catch of western spruce budworm moths, Choristoneura occidentalis Freeman, in pheromone traps were tested in light to moderate infestations near Ashcroft, B.C. High cumulative moth catches reduced the trapping efficiency of both the sticky traps and the non-sticky Uni-traps relative to traps from which the moths were removed every 2 days. Correlations between the total season’s catch and larval density per plot in the same and following generations were not significant (P>0.05) for any of the eight combinations of trap design, lure concentration, and maintenance regimen tested. However, by dividing the mean moth catch in Uni-traps by either the basal area or foliage biomass per hectare in each plot, correlations with the following year’s larval density were significant (r2 = 0.77–0.98; P<0.05; n=5).

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.


1982 ◽  
Vol 8 (2) ◽  
pp. 339-350 ◽  
Author(s):  
H. T. Cory ◽  
G. E. Daterman ◽  
G. D. Daves ◽  
L. L. Sower ◽  
R. F. Shepherd ◽  
...  

1992 ◽  
Vol 124 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Roy F. Shepherd

AbstractIndividual larvae of western spruce budworm (Choristoneura occidentalis Freeman) were observed from overwintering emergence to pupation at six locations spread over a wide range of altitudes and thus climate. A weekly census of 100 lower-crown buds per plot indicated large differences in rates of bud development and larval survival among locations.Emerging second-instar larvae attempted to mine swelling buds of Douglas-fir. If the buds were hard and tight, larvae mined 1-year-old needles until penetrable buds were available. Larvae dispersed over the crowns with only one larva becoming established in each bud; thus, many early-emerging and surplus larvae could not find suitable feeding sites and disappeared. Within the protective bud, survival was high. After buds flushed and larvae became exposed, densities dropped, probably due to increased predation and decreased food quality. Correlations indicated a close association between larval survival for the exposed period between bud flush and pupation, and overall larval survival.Douglas-fir trees responded to initial bud removal, but not to needle removal, by inducing latent buds in the axils of needles to grow into active vegetative buds ready to develop and flush the next spring. The number of these new vegetative buds formed was greatest when the initial buds were removed early in the season before flush, and decreased thereafter. Trees with vigorous crowns had the greatest response to defoliation by inducing the largest number of latent buds into becoming active vegetative buds; these were found mainly on the 2- and 3-year-old internodes.


1977 ◽  
Vol 109 (9) ◽  
pp. 1153-1158 ◽  
Author(s):  
J. Wayne Brewer ◽  
J. O’Neal

AbstractThe insecticide acephate (0.5-dimethyl acetyl phosphoramidothioate) was applied at 0.5, 1.0, and 1.5 lb A.I./gal (.058, 0.118, 0.179 kg/l.) in aqueous solution to individual Douglas-fir trees infested with western spruce budworm, Choristoneura occidentalis Freeman, larvae in central Washington using hand held ground application equipment. Application was made when larvae were in the needle mining – bud mining stage at rates ranging from 2.58 to 5.10 gal/acre (3.97 to 7.84 l./ha). For all three concentrations, mortality of larvae inside needles was 94–98% after 1 day compared with a check mortality of 18% and larval mortality inside buds was 99% after 1 day compared with 23% for the check. Regression analyses indicated that defoliation was positively correlated with the number of needles mined the current year and per cent punctured buds, and negatively correlated with larval mortality inside both needles and buds. The data suggest that when applied at the rates used, acephate has some type of systemic action and can provide foliage protection during the year of application.


1985 ◽  
Vol 117 (8) ◽  
pp. 961-969 ◽  
Author(s):  
R.C. Reardon ◽  
L.J. Barrett ◽  
T.W. Koerber ◽  
L.E. Stipe ◽  
J.E. Dewey

AbstractThe systemic insecticides oxydemeton-methyl and acephate were injected at 10- and 15-cm spacings, and acephate and dimethoate were implanted at 10-cm spacing in Douglas fir, Pseudotsuga menziesii var. glauca (Beissn.) Franco, to improve seed yield. Nutrients were also injected at 15-cm spacing. All treatments except nutrients and dimethoate increased the yield of filled seeds when compared with the checks. The western spruce budworm, Choristoneura occidentalis Freeman, and spruce coneworm, Dioryctria reniculelloides Mutuura and Munroe, caused most of the damage to cones.


2011 ◽  
Vol 143 (4) ◽  
pp. 384-387 ◽  
Author(s):  
L.M. Poirier ◽  
J.H. Borden

AbstractA choice feeding bioassay was used to investigate the effects of artificial diet components on the repellency of larval oral secretions from western spruce budworm, Choristoneura occidentalis Freeman, to conspecific larvae. Oral secretions from insects fed on agar supplemented with linseed oil were as repellent as secretions from insects fed on complete artificial diet. Secretions from insects fed on agar alone, agar and casein, or agar and wheat germ were not significantly more repellent than distilled water; neither was linseed oil alone. Linseed oil consists of glycerides of several fatty acids, which are likely metabolized quickly in the insect gut; repellency of oral secretions could be due to any of the related fatty acids or metabolites.


1980 ◽  
Vol 112 (10) ◽  
pp. 1001-1006 ◽  
Author(s):  
Jacqueline L. Robertson

AbstractSpray and feeding bioassays of acephate and carbaryl were conducted with each of the six instars of the western spruce budworm, Choristoneura occidentalis Freeman. Dose-mortality regressions were used to estimate overall relative susceptibility. Small differences in overall susceptibility of the six instars to acephate and large differences to carbaryl were observed. Application of carbaryl so that it would be present when second instars emerge from their hibernacula may maximize efficacy by minimizing the tolerance-instar effect. The efficacy of acephate may be relatively unaffected by instar-related changes in tolerance.


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