PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH (LEPIDOPTERA: LYMANTRIIDAE): A SEQUENTIAL SAMPLING METHOD TO DETERMINE EGG MASS DENSITY

1984 ◽  
Vol 116 (7) ◽  
pp. 1041-1049 ◽  
Author(s):  
R. F. Shepherd ◽  
I. S. Otvos ◽  
R. J. Chorney
Keyword(s):  
Sampling Method ◽  
Mass Density ◽  
Sequential Sampling ◽  
Douglas Fir ◽  
Egg Mass ◽  
Tussock Moth ◽  
Incipient Stage ◽  
Orgyia Pseudotsugata ◽  
Detection Tool ◽  
Variability Data

AbstractA sequential egg-mass sample system for Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough (Lepidoptera: Lymantriidae), was designed, based on visual scanning of the lower branches of Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco. A branch was removed from each quadrant from the upper, middle and lower crown level, and from the lowest whorl of a total of 59 non-defoliated trees in 10 areas. No consistent trend in egg-mass density per branch could be found between crown levels and no level proved superior as a representative of the tree. Therefore, the lower whorl of branches was selected for survey purposes because of sampling efficiency. Sample stop lines were determined from egg-mass density and variability data collected on 55 sites and subsequent defoliation estimates were related to these densities. The system is designed as an early detection tool to be used only in non-defoliated stands at the incipient stage of an impending outbreak.

PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE): MONITORING ENDEMIC POPULATIONS WITH PHEROMONE TRAPS TO DETECT INCIPIENT OUTBREAKS

1985 ◽  
Vol 117 (7) ◽  
pp. 839-848 ◽  
Author(s):  
R.F. Shepherd ◽  
T.G. Gray ◽  
R.J. Chorney ◽  
G.E. Daterman
Keyword(s):  
Pest Management ◽  
Mass Density ◽  
Douglas Fir ◽  
Population Cycle ◽  
Poor Correlation ◽  
Egg Mass ◽  
Pheromone Traps ◽  
Threshold Density ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata

AbstractThe numbers of Douglas-fir tussock moths (Orgyia pseudotsugata) (Lepidoptera: Lymantriidae) caught in sticky, delta-shaped pheromone traps baited with different concentrations of synthetic lures were compared with egg-mass densities and subsequent defoliation throughout a population cycle. A lure containing 0.01% pheromone by weight in the form of a 3 × 5-mm polyvinylchloride rod provided more consistent catches than pheromone concentrations of 0.0001, 0.001, 0.1, or 1.0%. Trap saturation occurred when >40 moths per trap were caught. To achieve a standard error of 30%, 6 traps were required at each site. There was a poor correlation between numbers of moths caught and egg-mass density or defoliation estimates in the following generation, but a threshold density was found that provides a warning of an incipient outbreak. Ground surveys for egg masses are recommended to confirm suspected infestations after continuous increases in moth catches for 2 to 3 years or if an average of 25 moths or more per trap has been caught.

AERIAL APPLICATION OF NUCLEAR POLYHEDROSIS VIRUS AGAINST DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (McDUNNOUGH) (LEPIDOPTERA: LYMANTRIIDAE): I. IMPACT IN THE YEAR OF APPLICATION

1987 ◽  
Vol 119 (7-8) ◽  
pp. 697-706 ◽  
Author(s):  
I.S. Otvos ◽  
J.C. Cunningham ◽  
L.M. Friskie
Keyword(s):  
Nuclear Polyhedrosis Virus ◽  
Mass Density ◽  
Adult Emergence ◽  
Douglas Fir ◽  
Egg Mass ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Population Reduction ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

AbstractFour 10-ha plots located in Kamloops Forest District, British Columbia, containing Douglas-fir trees infested with Douglas-fir tussock moth were aerially sprayed with nuclear polyhedrosis virus (Virtuss) in 1982 when most larvae were in the first instar. A dosage of 2.5 × 1011 polyhedral inclusion bodies (PIB) per hectare was applied in an emulsifiable oil tank mix to one plot and the same dosage in an aqueous tank mix containing molasses was applied to a second plot. The remaining two plots were treated with dosages of 8.3 × 1010 and 1.6 × 1010 PIB per hectare, respectively, in the oil mix. The treatments were applied with a fixed-wing aircraft fitted with boom and nozzle equipment and calibrated to deliver 9.4 L/ha. A further four plots were selected as checks.Population reduction at 6 weeks post-spray (calculated using a modified Abbott’s formula) was 65% in the plot receiving the lowest dosage and from 87 to 95% in the remaining three plots. Incidence of virus infection, determined microscopically, peaked at 5–6 weeks post-spray with 85–100% of the larvae scored as positive. Levels of naturally occurring virus remained low in the check plots. Adult emergence from the pupae collected in the treated plots ranged from 4 to 19% and from 28 to 43% in the check plots. Reduction in egg-mass density attributed to the treatments was 97% in one plot, 99% in two others, and not determined for the fourth.A virus dosage of 8.3 × 1010 PIB per hectare, which is one-third of the previously recommended dosage, is adequate, and either tank mix is acceptable.

DOUGLAS-FIR TUSSOCK MOTH (HEMEROCAMPA PSEUDOTSUGATA) EGG-MASS DISTRIBUTION ON WHITE FIR IN NORTHEASTERN CALIFORNIA

1967 ◽  
Vol 99 (11) ◽  
pp. 1193-1203 ◽  
Author(s):  
Robert F. Luck ◽  
Donald L. Dahlsten
Keyword(s):  
Sampling Method ◽  
Douglas Fir ◽  
Egg Mass ◽  
Egg Masses ◽  
Sample Unit ◽  
Tussock Moth ◽  
White Fir ◽  
Cardinal Direction ◽  
Sources Of Variation ◽  
Cardinal Directions

AbstractThe distribution of Douglas-fir tussock moth (Hemerocampa pseudotsugata McD.) egg-masses on white fir (Abies concolor (Gord. and Glend.) Lindl.) was studied in three areas of northern California. In each area 100 trees between 4.5 and 8.4 in. in diameter were stratified into five defoliation classes and four crown classes, giving a total of 20 classes per study area with five trees per class. Trees were divided into four crown levels and samples were taken at each of the cardinal directions at each level. Two branches comprised n sample unit in the top half of the tree (eight branches per level) and one branch the sample unit in the bottom half of the tree (four branches per level). Egg masses were recorded per 10 sq. ft of foliage or branch area. Eighty per cent or more of the egg masses were found in the bottom half of the crown. This percentage in the bottom half of the crown increased on trees with heavy defoliation or with increased exposure of the crown. Of the four possible sources of variation considered in this study, crown level, defoliation class, and crown class were significant while cardinal direction was not. A sampling method is proposed on the basis of the information gathered in this investigation.

PARASITOIDS AND PREDATORS OF THE DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIDAE), IN LOW TO MODERATE POPULATIONS IN CENTRAL CALIFORNIA

1977 ◽  
Vol 109 (5) ◽  
pp. 727-746 ◽  
Author(s):  
D. L. Dahlsten ◽  
R. F. Luck ◽  
E. I. Schlinger ◽  
J. M. Wenz ◽  
W. A. Copper
Keyword(s):  
Sierra Nevada ◽  
Egg Parasitoid ◽  
Host Population ◽  
Douglas Fir ◽  
Egg Mass ◽  
Moth Population ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
White Fir ◽  
Pupal Parasitoids

AbstractDouglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), populations were studied on white fir at four areas in central Sierra Nevada mountains of California during 1971–73. Life tables were constructed for four populations in El Dorado County. The number of eggs per egg mass decreased and the percentage eggs parasitized doubled with declining moth populations. Hymenopterous parasitoids were collected from all immature stages of the moth: one egg parasitoid, Telenomus californicus Ashmead, six species of larval parasitoids, principally, Hyposoter sp., and 13 species of larval–pupal parasitoids. Tachinids were predominant and accounted for 73% of the parasitoidism of the cocoons in 1971. The apparent mortality of female pupae due to the parasitoid complex was greater than 97% in 1971 and 75% in 1972. One population in Placer County collapsed in 1971 apparently due to a combination of heat exhaustion and low levels of virus infection. Other defoliators, spiders, and several predatory insect species were collected from the foliage samples simultaneously with the tussock moth during larval sampling. Twelve species of "free living" spiders which could be capable of preying on the defoliator complex of white fir were collected. Parasitoids and predators appear to be potentially important biotic factors at low to moderate host population levels. This is the first recorded case where an agent other than the nucleopolyhedrosis virus has been responsible for the collapse of a Douglas-fir tussock moth population.

scholarly journals Impact of Biochar on Douglas-Fir Tussock Moth (Orgyia pseudotsugata Lepidoptera: Erebidae) Larvae Reared on Synthetic Die

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1065
Author(s):  
Stacey Rice-Marshall ◽  
Stephen P. Cook ◽  
John Randall
Keyword(s):  
Weight Gain ◽  
Larval Mortality ◽  
Douglas Fir ◽  
High Concentration ◽  
Larval Weight ◽  
Synthetic Diet ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Compensatory Feeding ◽  
Significant Difference

The use of biochar as a soil amendment in forest ecosystems can be beneficial in the restoration of degraded soils. Forest insects such as the Douglas-fir tussock moth, Orgyia pseudotsugata (McDonnough) (Lepidoptera: Erebidae), may be exposed to biochar when the material is applied. Two experiments were conducted using biochar either (1) applied to the surface of the diet at three rates (0, 5, and 10 mg) or (2) incorporated into synthetic diet at four rates (0, 10, 20, and 40% volume/volume). The objective of both experiments was to determine if biochar on the surface or incorporated into a synthetic diet affected development and survival of O. pseudotsugata larvae. In both experiments, there was a significant decrease in estimated time to larval mortality in all biochar treatments compared to untreated controls. In the surface-applied biochar experiment, there was a significant difference in larval weight gain at day 12 between the control and 10 mg biochar treatments. In the experiment with biochar incorporated into the diet, mean larval weight at day 12 was highest in the low (10%) biochar treatment compared to all other treatments, although weight gain was only significantly different between the low- and high-concentration (40%) biochar treatments. Our results suggest that larvae, feeding on a low amount of biochar in the synthetic diet, may respond by engaging in compensatory feeding behavior. Fewer surviving larvae in the biochar treatment groups may contribute to the lack of significance found in the comparison of weight gain at day 24 in each experiment.

Incidence and impact of Entomophaga aulicae (Zygomycetes: Entomophthorales) and a nucleopolyhedrovirus in an outbreak of the whitemarked tussock moth (Lepidoptera: Lymantriidae)

2002 ◽  
Vol 134 (6) ◽  
pp. 825-845 ◽  
Author(s):  
K. van Frankenhuyzen ◽  
P. Ebling ◽  
G. Thurston ◽  
C. Lucarotti ◽  
T. Royama ◽  
...  
Keyword(s):  
Mass Density ◽  
Abies Balsamea ◽  
Larval Survival ◽  
Balsam Fir ◽  
Egg Mass ◽  
Population Changes ◽  
Tussock Moth ◽  
Orgyia Leucostigma ◽  
Recent Outbreak ◽  
Whitemarked Tussock Moth

AbstractIn Nova Scotia, the whitemarked tussock moth, Orgyia leucostigma Fitch, periodically erupts in outbreaks that typically last 3–5 years. Population changes during a recent outbreak were monitored by means of aerial defoliation surveys and fall egg-mass surveys that were conducted between 1997 and 2001. Severe defoliation was first recorded on approximately 250 ha in 1996. The defoliated area increased rapidly to hundreds of thousands hectares in 1998, after which it sharply declined to about 4700 ha in 2000 and 0 ha in 2001. The total infested area [>0.01 egg masses per three branches of Abies balsamea L. (Pinaceae)] decreased from about 1.4 million ha in 1997 to about 13 500 ha in 2001. Between 1996 and 2001, the infestation involved a cumulative total of 2.4 million ha, covering most of the province. The collapse of larval populations during 1998 was associated with widespread prevalence of a singly embedded nucleopolyhedrovirus (NPV) and Entomophaga aulicae (Reichardt in Bail) Humber (Zygomycetes: Entomophthorales). Sampling of larval populations in late July and August 1998 revealed a widespread and virtually sympatric occurrence of those pathogens in areas that were under defoliation pressure, with infection levels by each pathogen exceeding 75% in many sample sites. Pathogen impacts on larval survival were studied in 1999 in a persisting pocket of severe infestation in Hants County. Larvae were collected every 3 d from balsam fir branch samples between 17 June and 21 July and reared to determine cause of death. The two pathogens together accounted for at least 50% of cohort mortality, calculated as marginal mortality rates according to Royama (2001). Although cohort mortality due to disease on balsam fir was significantly correlated with between-generation reduction in mean egg-mass density, overall pathogen-induced mortality was not high enough to drive the populations into an endemic state, and a moderate infestation persisted into 2000.

TOXICITY OF INSECTICIDES TO DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE): I. CONTACT AND FEEDING TOXICITY

1979 ◽  
Vol 111 (10) ◽  
pp. 1145-1159 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Lucille M. Boelter
Keyword(s):  
Rhodamine B ◽  
Douglas Fir ◽  
Relative Toxicity ◽  
Spray Chamber ◽  
Population Response ◽  
Larval Stages ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Rhodamine B Dye ◽  
Spray Volume

AbstractThe toxicities of 14 insecticides to selected larval stages of the Douglas-fir tussock moth were determined with a laboratory spray chamber. The toxicities of 10 were also determined in feeding bioassays. Younger instars were, in general, more susceptible to the toxicants. Significant differences in population response from 1973 to 1977 precluded a rigid interpretation of relative toxicity values in relation to the standard for comparison, DDT. Spray volume, formulation, and the presence of rhodamine B dye significantly affected toxicities of two of the materials, carbaryl and trichlorfon. The degree of exposure of larvae to bioethanomethrin and carbaryl significantly affected mortality.

THE EFFECT OF TEMPERATURE AND FOOD DEPRIVATION ON SURVIVAL OF FIRST-INSTAR DOUGLAS-FIR TUSSOCK MOTHS (ORGYIA PSEUDOTSUGATA) (LEPIDOPTERA: LYMANTRIIDAE)

1983 ◽  
Vol 115 (6) ◽  
pp. 663-666 ◽  
Author(s):  
Roy C. Beckwith
Keyword(s):  
Food Deprivation ◽  
Larval Survival ◽  
Douglas Fir ◽  
Effect Of Temperature ◽  
Rearing Temperature ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
First Instar ◽  
Starvation Conditions

AbstractMortality of neonatal Douglas-fir tussock moth larvae varied from 0% to 100% depending on the rearing temperature and duration of food deprivation. Lower temperatures apparently favor larval survival under starvation conditions. For each period of food deprivation, mortality occurs earlier as the temperature increases; this shift to earlier mortality was significant at P <.01. Some implications are discussed.

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