EFFECT OF SUBLETHAL INFECTION LEVELS OF NOSEMA SP. ON THE PHEROMONE-MEDIATED BEHAVIOR OF THE WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN (LEPIDOPTERA: TORTRICIDAE)

1987 ◽  
Vol 119 (6) ◽  
pp. 587-594 ◽  
Author(s):  
J.D. Sweeney ◽  
J.A. McLean
Keyword(s):  
Sex Pheromone ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Adult Males ◽  
Western Spruce Budworm ◽  
Infection Level ◽  
Microsporidian Parasite ◽  
Wing Fanning ◽  
Antennal Response ◽  
Synthetic Sex Pheromone

AbstractWestern spruce budworm, Choristoneura occidentalis Freeman, adult males were observed in a wind tunnel for their response to synthetic sex pheromone and subsequently examined to determine their degree of infection with a microsporidian parasite, Nosema sp. A subsample of C. occidentalis was randomly selected and electroantennograms (EAG) of individual moths were measured for response to pheromone. The Nosema infection level ranged from 0 to 21.8 × 106 spores per milligram and was significantly negatively correlated with the proportion of males wing-fanning, taking off, and flying upwind to contact the pheromone source. The level of Nosema infection and the amplitude of the antennal response (EAG) to pheromone were not significantly related. These results suggest that Nosema affects the response of C. occidentalis males to pheromone in some way other than directly reducing the sensitivity of the antennae. We hypothesize that sublethal infections of Nosema sp. may reduce mating success of the western spruce budworm in field populations.

Chemistry and field evaluation of the sex pheromone of western spruce budworm,Choristoneura occidentalis, Freeman

1982 ◽  
Vol 8 (2) ◽  
pp. 339-350 ◽  
Author(s):  
H. T. Cory ◽  
G. E. Daterman ◽  
G. D. Daves ◽  
L. L. Sower ◽  
R. F. Shepherd ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Spruce Budworm ◽  
Field Evaluation ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm

RELATIONSHIPS BETWEEN ATTACK RATES AND SURVIVAL OF WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN (LEPIDOPTERA: TORTRICIDAE), AND BUD DEVELOPMENT OF DOUGLAS-FIR, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO

1992 ◽  
Vol 124 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Roy F. Shepherd
Keyword(s):  
Close Association ◽  
Spruce Budworm ◽  
Larval Survival ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Bud Development ◽  
Feeding Sites ◽  
Vegetative Buds ◽  
Wide Range

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.

EARLY GROUND APPLICATION OF ACEPHATE FOR CONTROL OF THE WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) ON DOUGLAS-FIR

1977 ◽  
Vol 109 (9) ◽  
pp. 1153-1158 ◽  
Author(s):  
J. Wayne Brewer ◽  
J. O’Neal
Keyword(s):  
Aqueous Solution ◽  
Larval Mortality ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Regression Analyses ◽  
Western Spruce Budworm ◽  
Systemic Action ◽  
Equipment Application

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.

IMPLANTATION AND INJECTION OF SYSTEMICS TO SUPPRESS SEED AND CONE INSECTS IN DOUGLAS FIR IN MONTANA,

1985 ◽  
Vol 117 (8) ◽  
pp. 961-969 ◽  
Author(s):  
R.C. Reardon ◽  
L.J. Barrett ◽  
T.W. Koerber ◽  
L.E. Stipe ◽  
J.E. Dewey
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seed Yield ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Systemic Insecticides ◽  
Filled Seeds

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.

Effect of artificial diet components on conspecific repellency of larval oral secretions from western spruce budworm (Lepidoptera: Tortricidae)

2011 ◽  
Vol 143 (4) ◽  
pp. 384-387 ◽  
Author(s):  
L.M. Poirier ◽  
J.H. Borden
Keyword(s):  
Fatty Acids ◽  
Wheat Germ ◽  
Artificial Diet ◽  
Linseed Oil ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Oral Secretions ◽  
Insect Gut ◽  
Choice Feeding

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.

CONTACT AND FEEDING TOXICITIES OF ACEPHATE AND CARBARYL TO LARVAL STAGES OF THE WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS (LEPIDOPTERA: TORTRICIDAE)

1980 ◽  
Vol 112 (10) ◽  
pp. 1001-1006 ◽  
Author(s):  
Jacqueline L. Robertson
Keyword(s):  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Relative Susceptibility ◽  
Larval Stages

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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