Observations on the feeding behaviour of late-instar larvae of Choristoneura fumiferana

2010 ◽  
Vol 142 (4) ◽  
pp. 388-392 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Sylvain Espinasse
Keyword(s):  
Bacillus Thuringiensis ◽  
Feeding Behaviour ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Eastern Spruce Budworm ◽  
Late Instar ◽  
Feeding Bout ◽  
Subsequent Interval ◽  
Observation Period

AbstractLaboratory observations revealed that late-instar larvae of the eastern spruce budworm (Choristoneura fumiferana (Clemens)) (Lepidoptera: Tortricidae) spend most of their time spinning, wandering, and resting; less than 10% is spent feeding. Larvae feed in a discontinuous pattern of short feeding bouts separated by much longer intervals of nonfeeding activity. Over a 2 h observation period, feeding bouts averaged 2.2 min and were separated by 17.4 min intervals for 4th-instar larvae as compared to 3.3 min bouts separated by 33.4 min intervals for 5th-instar larvae. The duration of a feeding bout was positively correlated with the duration of the subsequent interval, not with the duration of preceding intervals, suggesting that feeding-bout frequency is governed primarily by post-ingestion processes. It is postulated that short feeding bouts followed by long intervals limit the window for ingesting an efficacious dose of aerially applied insecticides such as Bacillus thuringiensis.

Interactions between Bacillus thuringiensis and parasitoids of late-instar larvae of the spruce budworm (Lepidoptera: Tortricidae)

2001 ◽  
Vol 79 (9) ◽  
pp. 1697-1703 ◽  
Author(s):  
Astrid Schoenmaker ◽  
Michel Cusson ◽  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Petri Dish ◽  
Control Treatment ◽  
Eastern Spruce Budworm ◽  
Late Instar ◽  
Host Mortality ◽  
Pathogen Exposure

We investigated interactions between Bacillus thuringiensis Berliner var. kurstaki and parasitoids that attack late instars of the eastern spruce budworm, Choristoneura fumiferana (Clemens). In a petri-dish arena, females of Tranosema rostrale rostrale (Brishke) (Hymenoptera: Ichneumonidae) were able to discriminate between untreated fourth instars and fourth instars that had been given a known dose of a commercial product (Foray 48B). When the choice tests were conducted before host mortality due to B. thuringiensis had occurred among treated larvae (24 h post ingestion), the parasitoid attacked untreated larvae more readily. When females were given a choice between control larvae and treated larvae that were still alive 72 h post ingestion, they were able to discriminate between the two only when the larvae had been treated with at least a 50% lethal dose. Under laboratory conditions, female T. r. rostrale were thus able to detect and avoid treated larvae that exhibited a lethal response to the pathogen, and to a lesser extent larvae that had survived pathogen exposure. The ability of the latter was not apparent under field conditions. When treated and untreated larvae were exposed for 1 week to a complex of indigenous parasitoids in the field, there was no difference between treatments in the rates of parasitism by either T. r. rostrale or Actia interrupta Curran (Diptera: Tachinidae). Parasitism averaged 91% for larvae in the control treatment compared with 92% for larvae treated with Foray 48B. The field data suggest that spruce budworm larvae that survive exposure to B. thuringiensis are just as likely to be parasitized as unexposed, healthy larvae. This means that prolonged development of late-instar spruce budworm larvae after treatment with B. thuringiensis could possibly result in increased attack rates by parasitoids.

FORECASTING THE EFFICACY OF OPERATIONAL BACILLUS THURINGIENSIS BERLINER APPLICATIONS AGAINST SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE), USING DOSE INGESTION DATA: INITIAL MODELS

1992 ◽  
Vol 124 (6) ◽  
pp. 1101-1113 ◽  
Author(s):  
Richard A. Fleming ◽  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Population Density ◽  
Choristoneura Fumiferana ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Initial Application ◽  
Eastern Spruce Budworm ◽  
Population Reduction ◽  
Support Tools ◽  
Image Position

AbstractSingle aerial applications of Bacillus thuringiensis Berliner (Bt) to control infestations of the eastern spruce budworm (Choristoneura fumiferana Clemens) have had varied operational success. Double applications are too expensive for general use, but might prove useful if directed to areas where the initial application was unsuccessful. This requires forecasts of the efficacy of the initial application in operational spray blocks within 4–5 days.Data were collected in 30 spray blocks in 1989 in a feasibility study to determine if such forecasts of spray efficacy could be made from the prespray budworm population density, N0, and from the proportion of the population that had ingested a lethal dose Bt within 2 days of application, M. A mathematical model forecasting the postspray budworm population density, NF, was derived from population-dynamic considerations and fitted (r2 = 0.48, p < 0.0001):The proportion of current foliage defoliated, D, depended (r = 0.81) on N0 and on whether the block was sprayed (I = 0) or not (I = 1):Only one measure of defoliation involved M in any statistically significant way. The predicted (from values of N0) proportion of defoliation prevented by Bt application, dD, was weakly (r2 = 0.25, p = 0.002) related to M:The large proportion of the variation in efficacy that remains unexplained by the models involving M limits the operational utility of this approach as it now stands for specific sites. The potential for further development of these models as decision support tools for fairly large spray blocks is discussed in terms of improving the sampling plan and including additional predictor variables.Methods are also presented that reduce bias in calculations of population reduction (Abbott 1925) and foliage protection when data are available from few control and many treatment blocks.

THEORETICAL OPTIMIZATION OF BACILLUS THURINGIENSIS BERLINER FOR CONTROL OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEM. (LEPIDOPTERA: TORTRICIDAE): ESTIMATES OF LETHAL AND SUBLETHAL DOSE REQUIREMENTS, PRODUCT POTENCY, AND EFFECTIVE DROPLET SIZES

1993 ◽  
Vol 125 (3) ◽  
pp. 473-478 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Nicholas J. Payne
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Sublethal Dose ◽  
Current Application ◽  
Feeding Inhibition ◽  
Eastern Spruce Budworm ◽  
Force Feeding ◽  
Droplet Sizes

AbstractWe present calculations of droplet sizes and product potencies that are theoretically required to deliver a lethal dose of Bacillus thuringiensis in one droplet to larvae of the eastern spruce budworm in aerial spray applications. The calculations are based on estimates of the dose required for 50% and 95% mortality [4.3 and 26.9 International Units (IU), respectively] and of the lowest dose that caused discernable feeding inhibition (0.5 IU) in force-feeding assays with sixth-instar larvae. For products containing 12.7–16.9 billion IU (BIU) per litre, the most widely used potency range, a 150- to 160-μm droplet is needed to deliver an LD95 and an 80- to 90-μm droplet to deliver an LD50, whereas droplets down to 40 μm are expected to cause extensive feeding inhibition. Our calculations suggest that current application prescriptions result in the delivery of a marginally effective dose to the target foliage and that budworm larvae have to ingest multiple droplets to obtain a lethal dose, a process that is thought to contribute to inconsistent spray efficacy. We predict that dose acquisition can be maximized by increasing product potency to 95 BIU/L, which would enable larvae to acquire a lethal dose by ingestion of only one or two droplets in the size range that is most commonly encountered on coniferous foliage (≤ 80 µm) after aerial application.

FACTORS AFFECTING ADULT EMERGENCE AND MATING BEHAVIOR OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1975 ◽  
Vol 107 (9) ◽  
pp. 967-977 ◽  
Author(s):  
C. J. Sanders
Keyword(s):  
Field Experiments ◽  
Choristoneura Fumiferana ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Field Conditions ◽  
Continuous Illumination ◽  
Degree Days ◽  
Factors Affecting ◽  
Eastern Spruce Budworm ◽  
Duration Of Copulation

AbstractLaboratory and field experiments indicate that the female spruce budworm (Choristoneura fumiferana (Clem.)) pupal stadium requires approximately 122C degree-days above a threshold of 7.2 °C (45°F), the male 124. Emergence time on any given day depends on temperature but is independent of photoperiod. Under field conditions male and female budworm mate only once per 24-h period. In the laboratory under continuous illumination females mate repeatedly and males readily mate a second time within a few hours, but the duration of the second copulation is abnormally long. The probability of multiple matings under field conditions is reduced by the restricted period of sexual activity coupled with the duration of copulation and the lower competitiveness of mated insects. Antennae are essential to the male for successful copulation.

LONG TERM STUDY OF THE EFFECTIVENESS OF AERIAL APPLICATION OF BACILLUS THURINGIENSIS – ACEPHATE COMBINATIONS AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Population Densities ◽  
Long Term Study

AbstractBacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

A METHOD FOR REARING THE LARVAL STAGES OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE), FOR PHYSIOLOGICAL STUDIES

1990 ◽  
Vol 122 (6) ◽  
pp. 1271-1272 ◽  
Author(s):  
Hemendra Mulye ◽  
Roger Gordon
Keyword(s):  
Population Dynamics ◽  
North America ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Spruce Budworm ◽  
Forest Pest ◽  
Forest Insect ◽  
Larval Stages ◽  
Eastern Spruce Budworm ◽  
Physiological Studies

The eastern spruce budworm, Choristoneura fumiferana Clemens, is the most widely distributed and destructive forest insect pest in North America. Although much is known about the ecology, population dynamics, and impact of C. fumiferana on tree growth (Sanders et al. 1985), there is very little information available on the physiology of this forest pest. Physiological studies are crucial to the development of novel strategies for spruce budworm control.

EFFECT OF TEMPERATURE ON THE PATHOGENESIS OF BACILLUS THURINGIENSIS BERLINER IN LARVAE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEM. (LEPIDOPTERA: TORTRICIDAE)

1994 ◽  
Vol 126 (4) ◽  
pp. 1061-1065 ◽  
Author(s):  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacterial Growth ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Effect Of Temperature ◽  
Vegetative Cells ◽  
Time Required ◽  
Peak Abundance

AbstractThe relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.

RELATIVE POTENCIES OF 50 ISOLATES OF BACILLUS THURINGIENSIS FOR LARVAE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1983 ◽  
Vol 115 (7) ◽  
pp. 815-822 ◽  
Author(s):  
O. N. Morris ◽  
A. Moore
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Growth ◽  
Spruce Budworm ◽  
Relative Potencies

AbstractFifty Bacillus thuringiensis (B.t.) isolates representing K-1, galleriae, K-73, thuringiensis, aizawai, dendrolimus, tolworthi, kenyae, darmstadiensis, alesti, and entomocidus crystal antigen types were bioassayed against fifth-instar spruce budworm, Choristoneura fumiferana (Clem.), larvae. In addition, larvae reared on diet with and without aureomycin were tested for their susceptibility to B.t. The data indicated no significant differences in susceptibility to B.t. among insects reared on aureomycin or on aureomycin-free diet, but differences were evident in larval growth and mortality among untreated controls. None of the 50 isolates bioassayed was any more toxic to the budworm than is the strain used at present in commercial preparations of B. thuringiensis.

THE ANTENNAE AS THE SITE OF PHEROMONE RECEPTORS IN THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1970 ◽  
Vol 102 (12) ◽  
pp. 1610-1612 ◽  
Author(s):  
P. J. Albert ◽  
W. D. Seabrook ◽  
U. Paim
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Eastern Spruce Budworm ◽  
Electrophysiological Recordings

AbstractElectrophysiological recordings are taken from the antennae of eastern spruce budworm males. These respond to crude pheromone extracts from the females. The pheromone receptors are located along the length of the antennae.

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