Diapause disruption with tebufenozide for early-instar control of the spruce budworm,Choristoneura fumiferana

2007 ◽  
Vol 63 (8) ◽  
pp. 730-736 ◽  
Author(s):  
Daniel Doucet ◽  
Caroline Frisco ◽  
Michel Cusson ◽  
Éric Bauce ◽  
Subba Reddy Palli ◽  
...  
1993 ◽  
Vol 125 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Beresford L. Cadogan ◽  
Roger D. Scharbach

AbstractThe insecticide Foray 48B (Bacillus thuringiensis var. kurstaki Berliner) was applied undiluted at 30 BIU per ha to control spruce budworm, Choristoneura fumiferana (Clem.), in a mixed boreal forest stand of balsam fir, Abies balsamea (L.) Mill., and black spruce, Picea mariana (Mill.) B.S.P. When the treatment was timed to coincide with the early flushing of balsam fir shoots, the corrected budworm population reductions were 74 and 52% on balsam fir and black spruce, respectively. This treatment resulted in 19 and 8% defoliation on the two respective species. When the insecticide application was timed later to coincide with the late flushing of black spruce shoots the corrected population reductions were 93% on balsam fir and 72% on black spruce. Defoliation of the two species was 29 and 10% respectively, following this treatment. Larval survival on both species after the spray timed for black spruce (0.8 and 2.2 larvae per 45-cm branch on balsam fir and black spruce, respectively) was significantly less (P = 0.05) than that observed after the spray timed for balsam fir (4.6 and 4.2 larvae per 45-cm branch on the respective host species).The data indicate that the spray timed to correspond with the flushing of black spruce was generally more efficacious than the spray timed to impact on newly flushed balsam fir; nevertheless, the results raise the question as to how B. thuringiensis insecticides impact on early-instar budworm larvae when there is no preferred current year foliage on which the insects can feed.


1983 ◽  
Vol 115 (11) ◽  
pp. 1523-1527 ◽  
Author(s):  
E. J. Dobesberger ◽  
K. P. Lim

AbstractRequired sample size was determined for early instar (2nd to 4th instar) larvae of spruce budworm,Choristoneura fumiferana(Clem.). Larval counts on mid-crown 45 cm branch tips and whole branches of balsam fir,Abies balsamea(L.) Mill., were described in terms of the negative binomial distribution. The values of commonkfor the branch tip and whole branch sample units were 1.550 and 1.636, respectively. The required sample size at densities greater than or equal to one appears feasible. It is recommended that the 45 cm branch tip be used to estimate population density of early instar larvae in Newfoundland.


Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 > 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.


1979 ◽  
Vol 8 (6) ◽  
pp. 993-996 ◽  
Author(s):  
W. P. Kemp ◽  
G. A. Simmons
Keyword(s):  

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.


1987 ◽  
Vol 119 (3) ◽  
pp. 251-263 ◽  
Author(s):  
S.M. Smith ◽  
M. Hubbes ◽  
J.R. Carrow

AbstractDuring 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.


1986 ◽  
Vol 62 (2) ◽  
pp. 96-100 ◽  
Author(s):  
D. J. McRae

Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.


1997 ◽  
Vol 129 (2) ◽  
pp. 291-318 ◽  
Author(s):  
Robert K. Lawrence ◽  
William J. Mattson ◽  
Robert A. Haack

AbstractSynchrony of insect and host tree phenologies has often been suggested as an important factor influencing the susceptibility of white spruce, Picea glauca (Moench) Voss, and other hosts to the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). We evaluated this hypothesis by caging several cohorts of spruce budworm larvae on three white spruce populations at different phenological stages of the host trees, and then comparing budworm performance with host phenology and variation of 13 foliar traits. The beginning of the phenological window of susceptibility in white spruce occurs several weeks prior to budbreak, and the end of the window is sharply defined by the end of shoot growth. Performance was high for the earliest budworm cohorts that we tested. These larvae began feeding 3–4 weeks prior to budbreak and completed their larval development prior to the end of shoot elongation. Optimal synchrony occurred when emergence preceded budbreak by about 2 weeks. Larval survival was greater than 60% for individuals starting development 1–3 weeks prior to budbreak, but decreased to less than 10% for those starting development 2 or more weeks after budbreak and thus completing development after shoot elongation ceased. High performance by the budworm was most strongly correlated with high levels of foliar nitrogen, phosphorous, potassium, copper, sugars, and water and low levels of foliar calcium, phenolics, and toughness. These results suggest that advancing the usual phenological window of white spruce (i.e. advancing budbreak prior to larval emergence) or retarding budworm phenology can have a large negative effect on the spruce budworm’s population dynamics.


1975 ◽  
Vol 107 (9) ◽  
pp. 967-977 ◽  
Author(s):  
C. J. Sanders

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.


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