The Effect of Jack-pine Staminate Flowers on the Size of Larvae of the Jack-pine Budworm, Choristoneura sp.

1950 ◽  
Vol 82 (2) ◽  
pp. 34-43 ◽  
Author(s):  
R. R. Lejeune

The jack-pine budworm, Ohoristoneura sp., was first recorded by Graham (5, 6) as a new variety or race on jack pine. Subsequent studies by Graham (6 showed that in the early stages of their development the larvae of this insect prefer jack-pine staminate flowers as a habitat. Population records from Manitoba and northwestern Ontario indicate that infestations of the jack-pine budworm are invariably associated with an abundance of staminate flowers.

1991 ◽  
Vol 123 (5) ◽  
pp. 1065-1075 ◽  
Author(s):  
V.G. Nealis

AbstractSixteen species of parasitoids were found attacking outbreak and collapsing populations of the jack pine budworm, Choristoneura pinus pinus Free. (Lepidoptera: Tortricidae), in several plots in northeastern and northwestern Ontario. The patterns of parasitism were similar among widely separated plots with only a few species consistently dominating the parasitoid fauna. The greatest difference in the pattern of parasitism was between sustained and collapsing infestations. Collapsing populations of jack pine bud-worm were associated with relatively high levels of parasitism by Meteorus trachynotus Vier. (Hymenoptera: Braconidae) and Lypha setifacies (West.) (Diptera: Tachinidae) which attacked the late larval stages of the budworm. The results are discussed in comparison with other jack pine budworm studies and with spruce budworm population studies.


1989 ◽  
Vol 121 (4-5) ◽  
pp. 373-387 ◽  
Author(s):  
T.J. Lysyk

AbstractA phenology model for jack pine budworm, Choristoneura pinus pinus Freeman, is presented. Linear and nonlinear relationships between temperature and the development of overwintering larvae, instars 2–7, and pupae are determined, as is variation in the development of each instar. The model uses as input daily maximum and minimum temperatures corrected for the effects of bark and bud microclimate and simulates the number of insects in each instar on a given calendar date. Variation in development of all stages is included. Simulations matched observed data well for north-central and northwestern Ontario in 1986, but overestimated time of development for northwestern Ontario in 1987. Simulations under low, medium, and high temperature conditions revealed that a nonlinear equation for rate of development was necessary for simulating emergence whereas linear rate equations were adequate for simulating development of the feeding instars. The combined effect of bud and bark microclimate on model performance was equal to that which resulted from the use of nonlinear developmental equations.


1943 ◽  
Vol 75 (11) ◽  
pp. 207-211 ◽  
Author(s):  
A. W. A. Brown ◽  
Margaret R. MacKay

During the past decade a severe outbreak of budworm has been in progress on jack pine in northwestern Ontario, following similar infestations in Michigan and Minnesota. It has been observed that budworm on jack pine does not spread to adjacent stands of balsam fir and spruce, and similarly that outbreaks on fir and spruce do not spread to adjacent jack pine stands.


Author(s):  
Daniel Henderson ◽  
Kevin Helm ◽  
Kathryn Jablokow ◽  
Seda McKilligan ◽  
Shanna Daly ◽  
...  

This paper focuses on comparing and contrasting methods for assessing the variety of a group of design ideas. Variety is an important attribute of design ideas, because it indicates the extent to which the solution space has been explored. There is a greater likelihood of successfully solving a design problem when a more diverse set of ideas is generated in the early stages of design. While there are three existing metrics for variety, it has not been established how well they correlate with each other, so it is unknown whether they provide similar assessments of variety. This uncertainty inspired our investigation of the three existing metrics and, eventually, the development of a new variety metric — all of which we compared statistically and qualitatively. In particular, 104 design ideas collected from 29 sophomore mechanical engineering students were analyzed using the existing and new variety metrics. We conducted correlation analyses to determine if the four metrics were related and to what degree. We also considered the qualitative differences among these metrics, along with where they might be used most effectively. We found varying levels of statistically significant correlations among the four metrics, indicating that they are dependent. Even so, each metric offers a unique perspective on variety and may be useful in different situations.


1992 ◽  
Vol 9 (3) ◽  
pp. 107-112 ◽  
Author(s):  
Laird W. Van Damme ◽  
Lisa Buse ◽  
Steve Warrington

Abstract The effects of microsite soil compaction on direct seeding of jack pine and black spruce were tested in conjunction with Bracke scarification. The compaction effect was achieved by manually tamping the seed spot. It was anticipated that compaction might decrease the number of seeds required to establish seedlings and extend the sowing season in Northwestern Ontario Experimental results showed that compaction increased the number of scalps stocked with jack pine by 30% after the first growing season. Compaction with a pyramidal surface doubled the percent stocked scalps over conventional sowing for the latest sowing date. Compaction may allow an extension of the jack pine sowing season from late June into early July. Still, early spring sowing provided the best overall results for both species. Compaction effects were not detected for black spruce. The experimental sowing rate of five seeds per scalp may have been insufficient to detect black spruce treatment responses on the dry mineral soil seed spots. North. J. Appl. For. 9(3):107-112.


1974 ◽  
Vol 52 (7) ◽  
pp. 817-821
Author(s):  
Gary A. Simmons ◽  
Norman F. Sloan

Predation by the eastern chipping sparrow, Spizella passerina (Bechstein), on the jack-pine budworm, Choristoneura pinus Freeman, was investigated in northern Michigan. Singing-male counts and bird-banding records provided estimates of bird populations, budworm consumption rates were estimated from observation cage results, and budworm populations were estimated from branch sample counts. Average rate of consumption of all life forms of the budworm was 7.8/h per bird and remained nearly the same regardless of the number of life stages of the budworm available. Overall consumption was 3000/acre (7500/ha) for adults, 600/acre (1500/ha) for juveniles, and 300/acre (750/ha) for nestlings over a 22-day feeding period, resulting in 0.92% budworm mortality. Methods of estimating juvenile and nestling consumption of budworm are presented.


1996 ◽  
Vol 26 (12) ◽  
pp. 2180-2190 ◽  
Author(s):  
Deborah G. McCullough ◽  
Lyle J. Buss ◽  
Larry D. Marshall ◽  
Jari Kouki

Stand-level mortality and top kill from a 1991–1993 jack pine budworm (Choristoneurapinuspinus Freeman) outbreak were surveyed annually in the Raco Plains area of the Hiawatha National Forest in Michigan's Upper Peninsula from 1992 to 1994. Defoliation was visually estimated and percentage of trees killed or top killed was determined in 104 stands. In 1994, tree mortality attributable to the outbreak averaged 8% and 17% of trees had dead tops. Current stand inventory data, including age, site index, basal area, and size, were acquired from the Hiawatha Forest. Stands were grouped on the basis of inventory variables used for jack pine management in the Lake States region of the United States. Differences in tree mortality and top kill between groups, and associations between tree mortality and inventory variables, were evaluated. Tree mortality was greater in overmature stands and in overstocked stands, but stand size had little effect. Contrary to expectations, mortality was lower on poor sites with low site index values than on better sites with higher site index values. Mortality was not related to abundance of open-grown, full-canopied wolf trees or to abundance of trees infected with pine gall rust (Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka (=Peridermiumharknessii J.P. Moore)). Amount of top kill was related to defoliation severity and was higher in overmature and understocked stands. Top kill was not strongly associated with amount of tree mortality or with inventory variables.


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