EFFECTS OF INSECT GROWTH REGULATORS ON THE WESTERN SPRUCE BUDWORM (CHORISTONEURA OCCIDENTALIS) (LEPIDOPTERA: TORTRICIDAE): II. FECUNDITY AND FERTILITY REDUCTION FOLLOWING LAST INSTAR TREATMENTS

1979 ◽  
Vol 111 (12) ◽  
pp. 1369-1380 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Richard A. Kimball
Keyword(s):  
Simple Model ◽  
Reproductive Factors ◽  
Female Parent ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Insect Growth Regulators ◽  
Fertility Reduction ◽  
Reproductive Effects ◽  
Population Reduction

AbstractThe fecundity and fertility of parent adult western spruce budworm, Choristoneura occidentalis Freeman, which survived treatment with IGRs in their last larval stage was assessed. With few exceptions, IGR treatment significantly reduced both reproductive factors regardless of whether the male or female parent had been treated. A simple model estimating population reduction in the F1-generation based on lethal and reproductive effects on the parents is described. If IGRs were applied at a dosage of 154 g/ha (ca. 2 oz/acre), the estimated percentages of F1 reduction which would result ranged from 74.6 (ZR-515) to 99+ (ZR-512 and Ro 10-3108 (oil)).

LABORATORY AND FIELD EVALUATION OF NEOAPLECTANA CARPOCAPSAE (RHABDITIDA: STEINERNEMATIDAE) AGAINST THE ELM LEAF BEETLE (COLEOPTERA: CHRYSOMELIDAE) AND THE WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE)

1981 ◽  
Vol 113 (9) ◽  
pp. 787-793 ◽  
Author(s):  
Harry K. Kaya ◽  
Arnold H. Hara ◽  
Richard C. Reardon
Keyword(s):  
Spruce Budworm ◽  
Field Evaluation ◽  
Leaf Beetle ◽  
Field Application ◽  
Dispersal Ability ◽  
Choristoneura Occidentalis ◽  
Laboratory Studies ◽  
Western Spruce Budworm ◽  
Elm Leaf Beetle ◽  
Population Reduction

AbstractLaboratory studies showed that elm leaf beetle, Pyrrhalta luteola (Müller), larvae and pupae were susceptible to the nematode Neoaplectana carpocapsae Weiser; adults were less likely to be infected because of their dispersal ability. Spruce budworm, Choristoneura occidentalis Freeman, larvae were susceptible to the nematode in the laboratory. Field application of the nematode in 2% aqueous Volck oil suspension against elm leaf beetle or spruce budworm larvae did not significantly reduce the populations when compared with controls. Desiccation of the infective nematodes may be a factor in the variable results for elm leaf beetle, and cool temperatures and rain may have been factors in the poor results for spruce budworm. However, significant population reduction occurred in nematode treatments against elm leaf beetle pupae in litter. This nematode may be used against beetle pupae in conjunction with other control tactics.

EFFECTS OF INSECT GROWTH REGULATORS ON THE WESTERN SPRUCE BUDWORM (CHORISTONEURA OCCIDENTALIS) (LEPIDOPTERA: TORTRICIDAE): I. LETHAL EFFECTS OF LAST INSTAR TREATMENTS

1979 ◽  
Vol 111 (12) ◽  
pp. 1361-1368 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Richard A. Kimball
Keyword(s):  
Growth Regulators ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Spray Application ◽  
Western Spruce Budworm ◽  
Insect Growth Regulators ◽  
Lethal Effects ◽  
Insect Growth ◽  
Model Combining ◽  
Combining Data

AbstractDosage–response relationships of seven insect growth regulators (IGRs) to last instar western spruce budworm, Choristoneura occidentalis Freeman, were determined by topical application, spray application, and diet incorporation bioassays. Mortality was defined as failure to emerge as a viable adult. In spray application experiments, four IGRs—ZR-512, ZR-619, ZR-1662, and Ro 10-3108—had LD50s of less than 70 g/ha (1 oz/acre). Relative lethal effectiveness, based on a simple model combining data from the three bioassays, was ZR-1662 > ZR-619 > ZR-512 > Ro 10-3108 > ZR-777 > ZR-587 > ZR-515. We concluded that several IGRs, applied to a population consisting primarily of last instars, would induce lethal effects at dosages comparable to dosages of several conventional insecticides.

AERIAL APPLICATION OF TWO BACULOVIRUSES AGAINST THE WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN (LEPIDOPTERA: TORTRICIDAE), IN BRITISH COLUMBIA

1989 ◽  
Vol 121 (3) ◽  
pp. 209-217 ◽  
Author(s):  
I.S. Otvos ◽  
J.C. Cunningham ◽  
W.J. Kaupp
Keyword(s):  
British Columbia ◽  
Nuclear Polyhedrosis Virus ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Granulosis Virus ◽  
Population Reduction ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

AbstractTwo viruses, one a nuclear polyhedrosis virus and the other a granulosis virus, were applied in an attempt to initiate epizootics in populations of western spruce budworm, Choristoneura occidentalis Freeman, on Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco, in southeastern British Columbia. Two 172-ha plots were aerially treated in 1982 with 9.0 kg of lyophilized, virus-infected larval powder that was formulated in an emulsifiable oil tank mix and applied at 9.4 L per hectare. Each plot was treated when larval populations were at the peak of the fourth instar. The nuclear polyhedrosis virus was applied at 5.4 × 1011 polyhedral inclusion bodies per hectare and the granulosis virus at 1.7 × 1014 capsules per hectare. Results showed that the granulosis virus treatment caused 34.6% population reduction (Abbott’s formula) and the nuclear polyhedrosis virus 51.8%. Larvae from treated and check plots were reared individually in the laboratory and the incidence of viruses, parasitoids, and successful adult emergence was recorded. Studies m these plots continued in 1983 and 1984. Although vertical transmission of both viruses was evident, their impact on budworm mortality was less than in 1982. Consequently, the epizootics were not sufficiently intense to control the target insect population.

JOINT ACTION OF A JUVENILE HORMONE ANALOGUE WITH BENZOYLPHENYLUREAS INGESTED BY WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS (LEPIDOPTERA: TORTRICIDAE)

1984 ◽  
Vol 116 (8) ◽  
pp. 1063-1068 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Kimberly C. Smith ◽  
Jeffrey Granett ◽  
Arthur Retnakaran
Keyword(s):  
Simple Model ◽  
Juvenile Hormone ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Independent Action ◽  
Western Spruce Budworm ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Response Range ◽  
Bay Sir 8514

AbstractMixtures of the juvenile hormone analogue (JHA) methoprene and each of three benzoylphenylureas (BPUs) were fed to sixth-instar western spruce budworm, Choristoneura occidentalis Freeman. The BPUs tested were diflubenzuron, BAY SIR 8514 (N-[(trifluoromethoxy)phenyl]carbamoyl-2-chlorobenzamide), and EL-127063 (N-[[[5-(4-bromphenyl)-6-metnyl-2-pyrazinyl]amino]carbonyl]-2-chlorobenzamide). Mixtures consisted of JHA:BPU combined in 1:9 proportions. Ingestion of methoprene combined with BAY SIR 8514 or diflubenzuron resulted in significantly lower mortality than expected under a simple model of uncorrelated, independent action. Ingestion of the mixture of methoprene and EL-127063, however, resulted in significantly enhanced toxicity over the upper response range (> 50% mortality).

VARIABLES AFFECTING THE PRACTICAL USE OF JUVENILE HORMONE ANALOGUES FOR CONTROL OF THE WESTERN SPRUCE BUDWORM (CHORISTONEURA OCCIDENTALIS) (LEPIDOPTERA: TORTRICIDAE)

1981 ◽  
Vol 113 (9) ◽  
pp. 827-844 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Richard A. Kimball
Keyword(s):  
Juvenile Hormone ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Stage Of Development ◽  
Reproductive Effects ◽  
Direct Exposure ◽  
Juvenile Hormone Analogues ◽  
Laboratory Bioassays ◽  
Residual Effectiveness

AbstractVariables affecting the efficacy of seven juvenile hormone analogues on western spruce budworm, Choristoneura occidentalis Freeman, were examined in laboratory bioassays. Those tested were epofenonane, hydroprene, kinoprene, methoprene, triprene, ZR-587, and ZR-1662. Selected intrinsic variables—stage of development, sex, and extent of direct contact with sprays—were examined in bioassays involving direct exposure of third instars, direct applications to three pupal age classes, and indirect applications to sixth instars. An extrinsic variable, persistence in the environment, was assessed by determining the residual effectiveness of each juvenile hormone analogue to sixth instars. Sixth instars, rather than third instars, appeared to be the target of choice for two reasons. First, less active ingredient would be required for equivalent mortality by the time of adult eclosion. Second, greater, more consistent, deleterious reproductive effects coupled with a lower incidence of sexual variation in lethal effectiveness, would occur. Pharate pupae and untanned pupae were very susceptible to most of the chemicals and may provide a secondary target for the primary target, sixth instars. The importance of direct chemical-insect contact in achieving maximum reproductive inhibition suggests that these chemicals might be used most effectively in ways such that contact can be maximized, as in ground applications. Finally, some juvenile hormone analogues such as epofenonane and ZR-1662 appeared to persist long enough to permit flexibility with respect to instar distribution in a population.

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.

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