Improved performance of the eastern spruce budworm on black spruce as warming temperatures disrupt phenological defenses

2021 ◽  
Author(s):  
Bastien Bellemin‐Noël ◽  
Stéphane Bourassa ◽  
Emma Despland ◽  
Louis De Grandpré ◽  
Deepa S. Pureswaran
2021 ◽  
Vol 4 ◽  
Author(s):  
Lorena Balducci ◽  
Philippe Rozenberg ◽  
Annie Deslauriers

In the long term, defoliation strongly decreases tree growth and survival. Insect outbreaks are a typical cause of severe defoliation. Eastern spruce budworm (Choristoneura fumiferana Clem.) outbreaks are one of the most significant disturbances of Picea and Abies boreal forests. Nevertheless, in boreal conifers, a 2-year defoliation has been shown to quickly improve tree water status, protect the foliage and decrease growth loss. It suggests that defoliation effects are time-dependent and could switch from favorable in the short term to unfavorable when defoliation duration exceeds 5–10 years. A better understanding of the effect of defoliation on stem radius variation during the needle flushing time-window could help to elucidate the relationships between water use and tree growth during an outbreak in the medium term. This study aims to assess the effects of eastern spruce budworm (Choristoneura fumiferana Clem.) defoliation and bud phenology on stem radius variation in black spruce [Picea mariana (Mill.) B.S.P.] and balsam fir [Abies balsamea (L.) Mill.] in a natural stand in Quebec, Canada. We monitored host and insect phenology, new shoot defoliation, seasonal stem radius variation and daytime radius phases (contraction and expansion) from 2016 to 2019. We found that defoliation significantly increased stem growth at the beginning of needle flushing. Needles flushing influenced the amplitude and duration of daily stem expansion and contraction, except the amplitude of stem contraction. Over the whole growing season, defoliation increased the duration of stem contraction, which in turn decreased the duration of stem expansion. However, the change (increase/decrease) of the duration of contraction/expansion reflects a reduced ability of the potential recovery from defoliation. Black spruce showed significantly larger 24-h cycles of stem amplitude compared to balsam fir. However, both species showed similar physiological adjustments during mild stress, preventing water loss from stem storage zones to support the remaining needles’ transpiration. Finally, conifers react to defoliation during a 4-year period, modulating stem radius variation phases according to the severity of the defoliation.


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.


1990 ◽  
Vol 122 (6) ◽  
pp. 1271-1272 ◽  
Author(s):  
Hemendra Mulye ◽  
Roger Gordon

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.


2018 ◽  
Vol 9 (1) ◽  
pp. 576-586 ◽  
Author(s):  
Deepa S. Pureswaran ◽  
Mathieu Neau ◽  
Maryse Marchand ◽  
Louis De Grandpré ◽  
Dan Kneeshaw

2016 ◽  
Vol 45 (6) ◽  
pp. 1333-1342 ◽  
Author(s):  
Deepa S. Pureswaran ◽  
Rob Johns ◽  
Stephen B. Heard ◽  
Dan Quiring

1997 ◽  
Vol 14 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Barry C. Kostyk ◽  
Kevin W. Wanner

Abstract A neem seed extract was applied to black spruce trees at two stages of reproductive development to control insect damage to the seed cones. Applied after pollination, neem had no effect on damage by the spruce cone maggot but did provide some protection against defoliation by the spruce budworm. Neem had no effect on the numbers of spruce budworm larvae for the first 9 days of the experiment, but after 23 days, populations declined on trees with two of three neem treatments compared to control trees. Neem reduced cone grazing damage by lepidopteran larvae when applied during the flowering stage. However, increased female flower abortion also resulted. The application of neem seed extract for controlling spruce budworm damage appears promising, but more information is needed on earlier applications in the field to determine if this product could be used operationally without causing substantial flower abortion. North. J. Appl. For. 14(1):40-43.


1998 ◽  
Vol 15 (3) ◽  
pp. 135-140 ◽  
Author(s):  
David A. MacLean ◽  
Wayne E. MacKinnon

Abstract Data from the assessment of current defoliation levels on 172,000 individual shoots from 6890 midcrown branches sampled from balsam fir and spruce stands were used to define sampling protocols for assessing defoliation caused by spruce budworm. The method was based on sampling one midcrown branch from each of x host trees per stand, and assessing defoliation of y individual shoots per branch. Both the number of shoots per branch and the number of branches required per stand varied with host species (balsam fir, white spruce, or red-black spruce) and with average defoliation level. Sample sizes required to estimate mean defoliation with 90% confidence that the confidence interval is ±10% ranged from 7 to 24 branches per stand and from 17 to 58 shoots per branch, with the largest samples required at moderate (31-70%) defoliation levels. Estimated costs of shoot and branch sampling and processing ranged from $40-110/stand, based on a 90% confidence level salary rate of $12(Can.)/hr, and excluding travel costs. Results can be applied using a preliminary assessment to determine the general defoliation level, which along with species, determines the required sample size. North. J. Appl. For. 15(3):135-140.


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