scholarly journals Defensive Traits during White Spruce (Picea glauca) Leaf Ontogeny

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 644
Author(s):  
Antoine-Olivier Lirette ◽  
Emma Despland

Changes during leaf ontogeny affect palatability to herbivores, such that many insects, including the eastern spruce budworm (Choristoneura fumiferana (Clem.)), are specialist feeders on growing conifer leaves and buds. Developmental constraints imply lower toughness in developing foliage, and optimal defense theory predicts higher investment in chemical defense in these vulnerable yet valuable developing leaves. We summarize the literature on the time course of defensive compounds in developing white spruce (Picea glauca (Moench) Voss) needles and report original research findings on the ontogeny of white spruce needle toughness. Our results show the predicted pattern of buds decreasing in toughness followed by leaves increasing in toughness during expansion, accompanied by opposite trends in water content. Toughness of mature foliage decreased slightly during the growing season, with no significant relationship with water content. Toughness of sun-grown leaves was slightly higher than that of shade-grown leaves. However, the literature review did not support the expected pattern of higher defensive compounds in expanding leaves than in mature leaves, suggesting that white spruce might instead exhibit a fast-growth low-defense strategy.

2019 ◽  
Vol 49 (12) ◽  
pp. 1633-1637 ◽  
Author(s):  
Stephanie R. Patton ◽  
Matthew B. Russell ◽  
Marcella A. Windmuller-Campione ◽  
Christopher B. Edgar

White spruce (Picea glauca (Moench) Voss) plantations have historically been an important source of high-quality forest products in the Great Lakes Region of North America. Thinning in spruce plantations is a common silvicultural practice for reducing competition and promoting resiliency to forest health threats such as eastern spruce budworm (Choristoneura fumiferana Clemens), a native forest pest of eastern North America. Spruce budworm larvae feed on the foliage of trees, which reduces growth and potentially causes mortality during an outbreak. There has been continual spruce budworm defoliation in northern Minnesota, U.S.A., since the mid-1950s, with higher levels of defoliation in the late 1990s. This research modeled the diameter growth response of white spruce 18 years after initial thinning in stands that presently range between 44 and 64 years old. Some stands received a second thinning in recent years. We used generalized nonlinear least squares and nonlinear mixed-effects models to estimate annual diameter growth using common tree and stand metrics. Growth model performance was improved by including thinning and frequency of spruce budworm defoliation as modifiers of diameter growth. Results of this study highlight how thinning in combination with insect disturbance affect diameter growth in white spruce plantations of northern Minnesota.


2019 ◽  
Vol 49 (3) ◽  
pp. 221-227 ◽  
Author(s):  
Dan Quiring ◽  
Leah Flaherty ◽  
Greg Adams ◽  
Andrew McCartney ◽  
J. David Miller ◽  
...  

A two-year field study was carried out to determine whether inoculating white spruce, Picea glauca (Moench) Voss, with a native endophytic fungus, Phialocephala scopiformis DAOM 229536 Kowalski & Kehr (Helotiales, Ascomycota), decreased the performance of eastern spruce budworm, Choristoneura fumiferana Clemens, developing on these trees. Second instars were reared at three densities in the mid crown and at one density in the lower, mid, and upper crown. Larval survival (i.e., survival of larvae to pupation) was lower on endophyte-inoculated trees than on control trees in the mid crown and especially the upper crown but was similar in the lower crown, resulting in a significant interaction between endophyte and crown level. A similar but marginally insignificant interaction was observed for overall survival up to adult emergence (i.e., total survival). Larval survival and total survival were approximately 22% and 19% lower, respectively, when developing in the upper crown of endophyte-inoculated trees than in control trees. Larval survival remained relatively constant, with increased density on control trees but decreased with density on endophyte-inoculated trees, resulting in a significant interaction between endophyte and larval density. Sex ratios of emerged adults and wing lengths of emerged females were not influenced by the endophyte. Our results suggest that endophytic fungi could be useful additions to integrated pest management programs.


Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 659 ◽  
Author(s):  
Dan Quiring ◽  
Greg Adams ◽  
Andrew McCartney ◽  
Sara Edwards ◽  
J. David Miller

Wild eastern spruce budworm (Choristoneura fumiferana Clemens) were reared on white spruce (Picea glauca (Moench) Voss) trees, half of which had been previously inoculated with a native endophytic fungus, Phialocephala scopiformis DAOM 229536 Kowalski and Kehr (Helotiales, Ascomycota). Survival up to pupation and up to adult emergence was approximately 27% higher for budworm juveniles that developed on control trees compared to trees inoculated with the endophyte. The endophyte did not influence the size or sex of survivors but did reduce defoliation by approximately 30%. Reductions in defoliation on endophyte-inoculated versus control trees, due to reductions in survival of juvenile budworms, suggests that tree inoculations with P. scopiformis could play an important role in integrated management programs against the eastern spruce budworm.


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.


Heredity ◽  
2018 ◽  
Vol 121 (2) ◽  
pp. 142-154 ◽  
Author(s):  
Claudia Méndez-Espinoza ◽  
Geneviève J. Parent ◽  
Patrick Lenz ◽  
André Rainville ◽  
Laurence Tremblay ◽  
...  

1971 ◽  
Vol 49 (7) ◽  
pp. 1005-1011 ◽  
Author(s):  
J. P. Kimmins

The amino acids of new and old foliage of flowering and non-flowering balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) were investigated using two-dimensional descending paper chromatography. The data were analyzed for variation associated with age of foliage, age of tree, and flowering condition. The concentration of foliar amino acids was greater in balsam fir than in white spruce, and greater in new foliage than old foliage.The difference in concentration between foliage of flowering and non-flowering trees was smaller. However, the new foliage of flowering fir had higher levels of most of the amino acids examined than any other foliage category. This appears to reflect the known suitability of these foliage categories for spruce budworm larvae. While the data presented do not quantify the ecological significance of this apparent correlation, they do support the theory that variations in the nutritional quality of host plants play a very important role in the dynamics of herbivore populations.


1981 ◽  
Vol 113 (10) ◽  
pp. 949-951 ◽  
Author(s):  
W. H. Fogal ◽  
D. A. Winston ◽  
S. M. Lopushanski ◽  
D. A. MacLeod ◽  
A. J. Willcocks

White spruce, Picea glauca (Moench) Voss, is a major commercial tree species used in reforestation programs throughout Canada, and seed requirements cannot be met in some years because of insect damage and the periodic nature of cone crops. The spruce budworm, Choristoneura fumiferana (Clem.), feeds on buds and cones of its hosts, causing a pronounced decrease in cone production (Schooley 1978). A current outbreak in northeastern Ontario poses a serious threat to white spruce seed supply from high value, managed seed production areas. Therefore, in 1979, we began an experiment to determine whether carbofuran, a systemic insecticide, could be used to protect buds and cones when applied to soil. We chose carbofuran because it has proved successful for control of some insects in seed orchards in the southeastern United States (DeBarr 1978)


1958 ◽  
Vol 34 (1) ◽  
pp. 39-47 ◽  
Author(s):  
J. R. Blais

The relationship between spruce budworm defoliation and radial growth at breast height for balsam fir and white spruce trees of merchantable size was studied in various stands in northwestern Ontario. Defoliation was recorded yearly for these stands from the beginning of the infestation, and radial growth measurements were obtained from increment cores. The first year of radial growth suppression was calculated by comparing the growth of the affected species with that of jack pine and red pine trees by means of a growth-ratio technique. Apparent suppression in balsam fir and white spruce varied between stands, and, generally, occurred at the earliest in the second year and at the latest in the fourth year of severe defoliation. A wide ring at the base of the tree coinciding with the first year of suppression as reported by Craighead was non-existent.


1975 ◽  
Vol 107 (7) ◽  
pp. 717-728 ◽  
Author(s):  
G. T. Harvey

AbstractAmylopectin added to a sugar-free wheat-germ diet was equal to or better than sucrose as a carbohydrate source, and appears to be readily utilized by the eastern spruce budworm (Choristoneura fumiferana (Clem.)). Larval growth on diets containing dextrins or potato starch shows that they are partly utilized. Starches from other sources, including those isolated from mature balsam fir (Abies balsamea (L.) Mill.) or white spruce (Picea glauca (Moench) Voss) needles, are not utilized to any extent, on the basis of larval growth on diets to which they have been added.Sixth-instar budworm reared on artificial diets contain amylase(s) in midgut and salivary gland homogenates, which show a low rate of digestion of starches from host foliage. However, the presence of appreciable starch in frass from foliage-fed insects and the apparent low utilizability of foliar starch indicate that the latter is not an important nutrient for the budworm under natural conditions.


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