The effects on small-mammal populations of aerial applications of Bacillus thuringiensis, fenitrothion, and Matacil® used against jack pine budworm in Ontario

1989 ◽  
Vol 67 (5) ◽  
pp. 1318-1323 ◽  
Author(s):  
Duncan G. L. Innes ◽  
James F. Bendell

In late June 1985, both operational and experimental aerial spraying was conducted against an outbreak of jack pine budworm (Choristoneura pinus) in northern Ontario. We report the effects of the insecticides Bacillus thuringiensis, fenitrothion, and Matacil® on populations of rodents and shrews in young (20 years) and medium-aged (40 years) jack pine (Pinus banksiana) plantations. Live, snap, and pitfall traps were used to monitor small-mammal populations from early June to late August on four sprayed plots and two control plots. We found no statistically significant differences in abundances that could be attributed to an insecticide. However, pitfall trapping suggested that the abundance of shrews was altered by the fenitrothion spray. Both the pattern and magnitude of shrew captures was different relative to a control and two other treatment plots. This difference may have resulted from the lack of available prey (arthropods) on the fenitrothion plot. With the exception of fenitrothion, our results agree with other studies which suggest that standard applications of insecticides to control forest insects have no detectable or only limited impact on small mammals.

1998 ◽  
Vol 28 (2) ◽  
pp. 228-233 ◽  
Author(s):  
Kimberly F Wallin ◽  
Kenneth F Raffa

The possibility that uneven within-tree feeding patterns by jack pine budworm (Choristoneura pinus pinus Freeman) larvae could be related to underlying variation in host jack pine (Pinus banksiana Lamb.) foliar water, nutrient, and monoterpene contents was considered. Choristoneura pinus pinus feeds disproportionately in the upper portion of the canopy and almost exclusively on the basal portions of needles. Within needles, the distribution of water, several nutrients, and monoterpenes varied significantly between the distal and basal sections. Water, nitrogen, sulfur, manganese, and zinc levels occurred in higher concentrations in the distal section of the needle, which would not be predicted based on C. pinus pinus feeding patterns. Phosphorus, potassium, calcium, iron, and copper were significantly higher in the basal section. Although the latter differences might be predicted based on C. pinus pinus feeding patterns, they were not strong (ranging from 7.8% to 36.4% relative differences, as compared with 10.7%-50.0% relative differences in the former group). By contrast, concentrations of foliar monoterpenes were more strongly associated with known feeding patterns of C. pinus pinus. These relative differences ranged from myrcene (26.8%) to limonene (44.79%). Thus, foliar differences affecting within-needle feeding selection appear more associated with allelochemicals than nutrients or water. In contrast with the within-needle associations between larval feeding and foliar chemistry, no associations between upper and lower canopy foliage were observed. Water, nutrients, and monoterpenes were evenly distributed across the upper and lower canopy locations. Thus, differential feeding between canopy locations cannot be explained by foliar constituents. Rather, it is more likely explained by other environmental factors, such as proximity to and density of reproductive and vegetative shoots.


1992 ◽  
Vol 70 (3) ◽  
pp. 505-510 ◽  
Author(s):  
M. I. Bellocq ◽  
J. F. Bendell ◽  
B. L. Cadogan

A simulated operational spray with Bacillus thuringiensis in a jack pine (Pinus banksiana) plantation near Gogama, Ontario, showed effects of the insecticide on the population structure, diet, and prey selection of the masked shrew, Sorex cinereus. During the pretreatment period, the abundance and population structure of S. cinereus were similar in the control and experimental areas. Although the total abundance of shrews was also similar after spraying, there were fewer adult males and more juveniles in the treated area than in the control. The emigration of adult males was apparently increased after spraying. Lepidopteran larvae and Araneae were the most abundant items in the diet. After spraying, more lepidopteran larvae were eaten on the control than on the treated area. Juveniles and adult females but not adult males shifted from lepidoptran larvae to alternative prey in the treated area. Generalist insectivores such as S. cinereus are more likely to control the abundance of arthropods and less likely to be impacted negatively by selective insecticides such as B. thuringiensis.


1988 ◽  
Vol 120 (12) ◽  
pp. 1101-1111 ◽  
Author(s):  
V.G. Nealis ◽  
T.J. Lysyk

AbstractData on the distribution of overwintering jack pine budworm (Choristoneura pinus pinus Free.) collected between 1985 and 1987 in northern Ontario are used to develop guidelines for sampling this stage of the budworm. Two alternative methods of expressing budworm density are considered: counting the number of budworms per metre of branch and counting the number per square metre of branch bark surface area. Estimates of budworm density for three levels in the tree’s crown are given for 4 site-years.Entire branches are recommended as the sample units as the use of 60-cm branch-tip sections resulted in consistent underestimation of actual density per branch. Jack pine budworm density did not vary among cardinal compass directions and was generally highest at mid-crown levels.The distributions of two parasitoids, Apanteles fumiferanae Vier. and Glypta fumiferanae (Vier.), which overwinter as an egg or first-instar larva within the jack pine budworm, also were considered. Apanteles was the most abundant parasitoid at all crown levels at all sites examined. Percentage parasitism by Apanteles was highest and that by Glypta was lowest on the branch-tip sections in relation to the branch-basal section, but total percentage parasitism was relatively constant over the entire branch, throughout the tree crown, and from tree to tree. Consequently, the sampling method for jack pine budworm is easily extended for estimating the rate of parasitism and therefore for providing a prediction of mortality that results from these two common parasitoids.


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.


2008 ◽  
Vol 57 (1-6) ◽  
pp. 333-340 ◽  
Author(s):  
M. Ranger ◽  
K. K. Nkongolo ◽  
P. Michael ◽  
P. Beckett

Abstract Metal accumulation in soil and plant tissues has caused severe ecological damage in forest ecosystems in the Sudbury region. The main objective of the present study was to determine the levels of genetic diversity in jack and red pine populations growing in metal contaminated and uncontaminated areas. Newly introduced populations were compared to 40 to 60 old populations. For jack pine, the percentage of polymorphic loci (P %) ranged from 14.6% to 45.8% with a mean of 31.6%. Nei’s gene diversity (h) varied from 0.046 to 0.169 with an average of 0.100, and Shannon’s index (I) ranged from 0.070 to 0.250 with an average of 0.153. The level of genetic variation was much lower in the red pine populations. For this species, the level of polymorphic loci varied from 4.55% to 27.27%. The mean for Nei’s gene diversity and Shannon’s information index, were 0.034 and 0.053, respectively. The highest genetic diversity values were observed in new plantations being developed by the Sudbury reforestation program. Overall, the genetic distance among the Pinus banksiana populations revealed that all the populations analyzed were genetically close to each other. There was no association between metal accumulation and genetic diversity for both species.


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