THE BIOLOGY OF CANADIAN BARKBEETLES: THE SEASONAL HISTORY OF DRYOCOETES CONFUSUS SW

1931 ◽  
Vol 63 (11) ◽  
pp. 247-248 ◽  
Author(s):  
W. G. Mathers

The seasonal history of Dryocoetes confusus Sw., in trunks of Abies lasiocarpa (Hook) Nutt., as found under cage conditions at Stanley, B.C., during the two years 1929 and 1930 is summarized in the following statement.

1922 ◽  
Vol 14 (1-10) ◽  
pp. 219-289 ◽  
Author(s):  
P. A. Glenn

To secure accurate data in regard to the life history and the seasonal history of the codling-moth in Illinois, and the relation of climatic conditions to the rate of development and the time of appearance of the various stages of the insect, an investigation was begun in the spring of 1915 under the direction of Doctor S. A. Forbes, then State Entomologist.


2006 ◽  
Vol 36 (11) ◽  
pp. 2974-2982 ◽  
Author(s):  
Dominik Kulakowski ◽  
Thomas T Veblen

In the subalpine forests of the Colorado Rocky Mountains, research on disturbances that have occurred over the past several decades has shown that prior occurrence of disturbances can alter the extent and severity of subsequent disturbances. In the current study, we consider how fire history affected stand susceptibility to a mid-19th century spruce beetle (Dendroctonus rufipennis Kirby 1837) outbreak. Twenty-one sites were randomly located in an Engelmann spruce – subalpine fir (Picea engelmannii Parry ex Engelm. – Abies lasiocarpa (Hook.) Nutt.) forest across ~2000 km2 of the Grand Mesa area, Colorado. At each site, dendrochronological methods were used to reconstruct the history of severe fires and beetle outbreak. Stand-origin dates were estimated by collecting increment cores from 20–27 of the largest trees at each sample site. The beetle outbreak was reconstructed based on coincident releases among nonhost trees that survived the outbreak. Forest stands originated following severe fires in ca. 1790, ca. 1740, and ca. 1700. The 1840's outbreak affected 67% of these stands. Stands that initiated following the ca. 1790 fire were less susceptible to the outbreak than older stands. These findings indicate that stand-replacing fires have mitigated susceptibility to outbreaks of spruce beetles not only during recent outbreaks, but also over the past centuries.


1965 ◽  
Vol 43 (5) ◽  
pp. 563-570 ◽  
Author(s):  
A. C. Molnar

Unexplained mortality associated with attacks of the western balsam bark beetle (Dryocoetes confusus Sw.) in alpine fir (Abies lasiocarpa (Hook.) Nutt.) was found to be caused by a beetle–fungus complex. Not all trees attacked were killed, but surviving trees were left with lesions which provided potential entrance courts for decay fungi. Four closely related fungi, isolated from necrotic lesions centered at beetle bore holes, were shown by inoculation to be pathogenic. Ceratocystis dryocoetidis Kendrick and Molnar was the most virulent of these fungi on the basis of the size of lesions produced. C. dryocoetidis caused cambial and inner bark necrosis, while the other three fungi produced necrosis and blue staining of the sapwood.


1994 ◽  
Vol 126 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Alejandro D. Camacho ◽  
John H. Borden

AbstractThe response of the western balsam bark beetle, Dryocoetes confusus Swaine, to subalpine firs, Abies lasiocarpa (Hook.) Nutt., baited with (±)-exo-brevicomin (EXOB) or 9:1 blends of EXOB and endo-brevicomin (ENDOB), in two chiral combinations: (+):(±) and (+):(+), was assessed in a heavily infested stand in British Columbia. Unbaited control trees were not attacked, and the proportion of mass-attacked baited trees was similar for all other treatments. However, trees baited with the (+):(+) blend had the highest number of attacks per square metre, and they were also surrounded by the most attacked trees. The (+):(±) blend was intermediate in attractancy, and (±)EXOB was the least attractive bait. Pheromone-based management of D. confusus infestations may be more effective with the 9:1 blend of (+)EXOB:(+)ENDOB than with the previously used (±)EXOB baits.


1971 ◽  
Vol 103 (7) ◽  
pp. 947-961 ◽  
Author(s):  
Gordon W. Frankie ◽  
C. S. Koehler

AbstractLaspeyresia cupressana (Kearfott) (Lepidoptera: Olethreutidae) bores in the scale tissue of cones, the healthy phloem tissue of branch nodes and trunks, and damaged sites on plants of certain Cupressaceae and Taxodiaceae. The moth primarily attacks Cupressus macrocarpa Hartw. in coastal California where it passes through two generations annually, one in spring–summer and the other in fall–winter. Several parasites and predators were regularly found associated with Laspeyresia in the cones. Branch and trunk feeding occasionally is severe, but was never observed to cause dieback or tree death. The moth was frequently observed infesting sites on plants damaged by the fungus Coryneum cardinale Wagener.


1959 ◽  
Vol 91 (12) ◽  
pp. 798-806 ◽  
Author(s):  
J. A. Mutchmor

In southwestern Ontario the European corn borer, Ostrinia nubilalis (Hbn.), produces two flights annually. The first flight, beginning in June, consists of moths from larvae that have overwintered. The midsummer, or second, flight begins late in July or early in August, and its moths are the progeny of the first flight. Until about 20 years ago the borer produced only one annual flight and was thought to be univoltine. The change in the seasonal history of the borer in Ontario was described by Wressell (1953) and Miller (1956). The literature describing similar changes in parts of the United States has been reviewed by Lees (1955) and Everett et al. (1958). Wressell (1953) summarized light trap collection data of moth flights in the Chatham, Ontario, area for the years 1932 to 1951. The summary includes the percentage of the moths that were from the midsummer flight, and it is evident that the size of this flight varies greatly from year to year. Aside from its intrinsic interest, it would be of some economic value to know what governs the size of the midsummer flight. This is a report of studies undertaken to examine the case, and to relate the findings to the larger problem of why the borer now produces a second flight where formerly it produced only one.


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