Wood losses and economical threshold of <i>Btk</i> aerial spray operation against spruce budworm

Fournier, Cédric; Bauce, Éric; Dupont, Alain; Berthiaume, Richard

doi:10.1002/ps.1878

Cited by 16 publications

(10 citation statements)

References 25 publications

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“…Therefore, it would not be advisable to conduct a thinning 1 year before or during a spruce budworm outbreak, unless this treatment were accompanied with aerial sprays of the microbial insecticide Btk . This insecticide can protect trees during this period of low resistance to the insect, as it prevents substantial balsam fir mortality and growth losses 45. The effect caused by thinning is consistent with the findings of Piene and MacLean10, 11 and Bauce 7.…”

Section: Resultssupporting

confidence: 81%

Site factors and management influence short‐term host resistance to spruce budworm, Choristoneura fumiferana (Clem.), in a species‐specific manner

Fuentealba¹,

Bauce²

2011

Pest Management Science

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Thinning reduced balsam fir resistance to spruce budworm defoliation. This response is due to increased defoliation linked to reduction in concentrations of certain monoterpenes, and a decrease in foliage production, except on hydric drainage, demonstrating the importance of drainage class to tree resistance. The results suggest that the use of Bacillus thuringiensis might be required when conducting stand thinning during spruce budworm outbreaks.

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Section: Resultssupporting

confidence: 81%

Site factors and management influence short‐term host resistance to spruce budworm, Choristoneura fumiferana (Clem.), in a species‐specific manner

Fuentealba¹,

Bauce²

2011

Pest Management Science

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“…In other words, unprotected plots lost in average 29.9 m3/ha more balsam r volume due to spruce budworm-related mortality than protected plots. These results are in accordance with previous studies (Batzer 1973;Fournier et al 2010), con rming that aerial spraying of insecticides can substantially reduce balsam r mortality during spruce budworm outbreaks. The higher reduction in balsam r mortality reported in this study as compared with the reduction reported by Fournier et al (2010) (29.9 vs 20.5 m3/ha respectively) for the Ottawa River Valley highlights the importance of conducting assessments of the e cacy of protection programs at the end of the outbreak and over large areas to have a better appraisal of treatment e cacy because tree and stand characteristics may affect stand vulnerability to forest pests (MacLean 1980;Fuentealba et al 2013) and can therefore reduce treatment e cacy by affecting stand resistance in certain regions.…”

Section: Discussionsupporting

confidence: 93%

“…MacLean et al (1984) reported that there was little difference in spruce and global (spruce and balsam r combined) mortality between protected and unprotected stands whereas balsam r mortality was lower in protected stands than it was in unprotected stands but this host formed only a minor component of the sampled stands. More recently, Fournier et al (2010) reported an average reduction in tree mortality of 20.5 m3/ha in protected stands with Btk as compare with unprotected stands after 9 years. However, these studies have either been conducted during an outbreak (MacLean et al 1984) or restricted to a particular region (Northern Minnesota (Batzer 1973) and Ottawa River Valley (Fournier et al 2010)) which do not permit to do a complete appraisal of treatment e cacy because tree mortality continues several years after the end of the outbreak (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, Fournier et al (2010) reported an average reduction in tree mortality of 20.5 m3/ha in protected stands with Btk as compare with unprotected stands after 9 years. However, these studies have either been conducted during an outbreak (MacLean et al 1984) or restricted to a particular region (Northern Minnesota (Batzer 1973) and Ottawa River Valley (Fournier et al 2010)) which do not permit to do a complete appraisal of treatment e cacy because tree mortality continues several years after the end of the outbreak (e.g. Blais 1981a) and the fact that tree and stand characteristics may affect host and stand vulnerability (MacLean 1980;Fuentealba et al 2013) and therefore the long-term e cacy of insecticide treatments.…”

Section: Introductionmentioning

confidence: 99%

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Efficacy of Insecticide Aerial Spraying Programs to Reduce Tree Mortality During a Spruce Budworm Outbreak (1967‒1992) in the Quebec Province.

Fuentealba

Dupont

Quezada-García

et al. 2021

Preprint

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Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in Eastern North America. The main approach to protect Quebec forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial spraying of insecticides in the global forest protection strategy, little is known about its real impact on tree mortality reduction or the stand characteristics that may affect its long-term efficacy. We evaluate the efficacy of the protection program implemented between 1967 and 1992 in reducing tree mortality during the previous outbreak in Quebec and how its efficacy is affected by stand characteristics such as drainage quality and stand age. We established 422 plots in Eastern Quebec based on the following parameters: insecticide application (0-13 years), stand composition, drainage quality, and stand age at the beginning of the previous outbreak. Our results show that unprotected plots exhibited in average between 18 and 32.6% higher mortality than protected plots. Insecticide efficacy was affected by drainage quality. For example, protected plots established on sites with bad drainage quality exhibited 49% less balsam fir mortality than unprotected plots. Furthermore, immature and mature protected stands exhibited a similar reduction in balsam fir mortality (32.2 and 32.1% less mortality respectively) compare to unprotected stands. Our results may be useful for decision-makers not only to decide where and when apply insecticides during a spruce budworm outbreak but also, they may help to determine the pertinence of continuous protection during longer than usual outbreaks depending on protection goal.

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“…Current (2012) spruce budworm management programs seek to mitigate economic losses by protecting host trees from defoliation (Fournier et al 2009). An early intervention strategy has been proposed to prevent defoliation but the success of this strategy ultimately depends on spruce budworm population dynamics (Régnière et al 2001).…”

Section: Mating Disruption and Early Intervention Strategymentioning

confidence: 99%

C. P. Alexander review

2012

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The Canadian registration in 2007 of Disrupt SBW Micro-Flakes®, a pheromone-based product for control of spruce budworm,Choristoneura fumiferana(Clemens), paved the way for large-scale trials to test the practicality of mating disruption as a commercial pest management strategy. We review results from field and laboratory experiments on pheromone-based mating disruption of spruce budworm conducted from 1974 to 2008. Application of pheromone from the ground or the air consistently reduced the orientation of males toward pheromone sources. Mating disruption also reduced the mating success of caged or tethered females in 15 of 16 field studies where this parameter was recorded, but had only a limited effect on the mating success of feral females. No consistent difference in the density of egg masses in control and treated plots was observed, which has often been attributed to immigration of gravid females into pheromone-treated plots. Laboratory studies suggest that false-trail following is the predominant mechanism underlying mating disruption in spruce budworm. The enhanced mating success of females with increasing population density suggests that mating disruption should target low-density emergent populations during the initial phase of an outbreak. Constraints that may limit the potential of mating disruption as a management tool include (1) difficulties associated with obtaining accurate sampling estimates at low population density to forecast the onset of outbreaks, (2) potential behavioral adaptations by which females enhance their mating success when the atmosphere is treated with pheromone, and (3) long-range dispersal of females by flight.

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Wood losses and economical threshold of Btk aerial spray operation against spruce budworm

Abstract: An economic assessment of Btk treatments indicates that biopesticide aerial spraying operations are justified, as they prevented substantial balsam fir mortality and growth losses over the 9 year study.

Cited by 16 publications

References 25 publications

Site factors and management influence short‐term host resistance to spruce budworm, Choristoneura fumiferana (Clem.), in a species‐specific manner

Site factors and management influence short‐term host resistance to spruce budworm, Choristoneura fumiferana (Clem.), in a species‐specific manner

Efficacy of Insecticide Aerial Spraying Programs to Reduce Tree Mortality During a Spruce Budworm Outbreak (1967‒1992) in the Quebec Province.

C. P. Alexander review

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