A Survey of Parasites of the Larch Sawfly (Pristiphora erichsonii (Hartig)) in Manitoba and Saskatchewan

1954 ◽  
Vol 86 (8) ◽  
pp. 337-345 ◽  
Author(s):  
R. R. Lejeune ◽  
V. Hildahl

Records indicate that the present outbreak of the larch sawfly in Manitoba and Saskatchewan began about 1938 in the Spruce Woods-Riding Mountain area of Manitoba. Since then, it has spread in all directions where the principal host tree, larch, Larix laricina (Du Roi) K. Koch, occurs. It now includes nearly all of Manitoba and Saskatchewan, northwestern Ontario, part of northeastern Alberta, and northern Minnesota. In 1944, an annual survey of parasites that attack larvae of the larch sawfly was begun by the Forest Biology Laboratory, Winnipeg. The purposes of the survey were to determine (a) the principal species of parasites, (b) their abundance and effectiveness, and (c) .host-parasite population trends.

1959 ◽  
Vol 91 (8) ◽  
pp. 496-500 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice

The Forest Insect Survey at the Forest Biology Laboratory, Winnipeg, has been compiling records for a number of years on the percentage of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), parasitized by the tachinid Bessa harveyi Tnsd. Sawfly cocoons were collected each fall from the soil in infested stands, and those containing living larvae were dissected to determine the percentage of parasitism by B. harveyi. These estimates have been used to provide an index of parasitism (Lejeune and Hildahl, 1954), but are of limited value for a number of reasons: (1) estimates can be expressed only as percentage of sound cocoons parasitized; (2) total parasitism cannot be estimated because a portion of the parasites emerge from the cocoons before collection; and (3) estimates of parasitism may not be representative of the stand because there is a tendency to collect cocoons where they are easiest to find; hence all the cocoons in a collection may be from one or two small areas. If the proportion of cocoons containing B. harveyi varies within a stand such collections may give unreliable estimates of parasitism.


1959 ◽  
Vol 91 (5) ◽  
pp. 275-282 ◽  
Author(s):  
C. H. Buckner

Current investigations at the Forest Biology Laboratory, Winnipeg, are being directed towards the formulation of life tables for the larch sawfly, Pristiphora erichsonii (Htg.) (Lejeune, 1955). Because small mammal predation is a major factor in reducing cocoon populations of the sawfly (Buckner, 1953), an adequate method of assessing this source of mortality is desirable


1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.


1955 ◽  
Vol 87 (3) ◽  
pp. 103-111 ◽  
Author(s):  
H. C. Coppel ◽  
K. Leius

The larch sawfly, Pristiphora erichronii (Htg.), is currently considered a major forest insect pest in Canada. At the present time within Canada, the sawfly reacts to parasitism by Mesoleius tenthredinis Morley in two ways. In Manitoba and Saslratchewan the sawfly encapsulates approximately 100 per cent of the parasite eggs deposited, whereas in British Columbia encapsulation rarely exceeds four per cent (Muldrew, 1953). The reasons for the difference in degree of encapsulation are apparently unknown; however, since the origin of the sawfly itself is obscure, the possibility exists that a native species, an introduced species, Or a combination of both may he present, or that geographical or ecological units may have arisen. Studies now under way by officers of the Forest Biology and Entomology divisions are attacking the problem of identity and origin following the pattern established for the European spruce sawfly, Diprion hercyniae (Htg.). In this instance, as with the larch sawfly, parasites were introduced on the assumption that the pest had been introduced from Europe. Critical investigations by Reeks (1941) and Balch, Reeks, and Smith (1941), involving morphological, cytological, and other biological characters, showed that the species occurring in North America was one of two species common in Europe, and previously referred to there as Gilpinia polytoma (Htg.). Balch et al. (1941) showed that D. hercyniae had been introduced into North America.


1968 ◽  
Vol 100 (5) ◽  
pp. 470-475 ◽  
Author(s):  
R. J. Heron

AbstractLarvae of the larch sawfly, Pristiphora erichsonii (Htg.), were fed foliage of tamarack, Larix laricina (Du Roi) K. Koch, treated with solutions of the vital dyes, Nile blue sulphate, rhodamine B, and coriphosphine O, to determine their suitability as markers. Coriphosphine O was highly toxic at the concentrations administered but successful tagging was obtained with the other two dyes. Optimal dye retention and survival were obtained when larvae were fed for 3 days early in the last stadium using Nile blue sulphate and throughout the last stadium using rhodamine B.Both dyes persisted throughout development and were incorporated in the cocoons and the oviposited eggs. They could be readily seen in all stages except for the cocoons and for eggs that contained rhodamine B. The dyes could be detected in cocoons by treating them with cold KOH followed by ethanol. The presence of rhodamine B in the eggs could be ascertained by its yellow fluorescence in ultraviolet.The dyes incorporated in the cocoons are relatively stable and laboratory tests indicate they probably can withstand weathering under normal field conditions over a 1-year period.The use of these dyes for internal marking should prove useful in studying adult dispersal and flight range and as a technique for use in population studies of the larch sawfly.


1961 ◽  
Vol 93 (3) ◽  
pp. 228-238 ◽  
Author(s):  
F. T. Bird ◽  
J. M. Burk

An outbreak of the European spruce sawfly, Diprion hercyniae (Htg.), occurring in Eastern Canada between 1930 and 1942, was controlled by a virus disease (Balch and Bird, 1944). The sawfly has been kept at a low level by the disease and by parasitic insects introduced from Europe (Bird and Elgee, 1957).An infestation of the sawfly was discovered in 1947 near Sault Ste. Marie, Ontario, by the Forest Insect Survey Section of the Forest Biology Laboratory at Sault Ste. Marie. This infestation was about 100 miles beyond the previously known western distribution of the insect. Intensive larval sampling in 1949 showed that it was free from virus and practically free from introduced parasites. Thus, an excellent opportunity was provided to introduce the virus into a disease-free population, to study its establishment and spread, and to compare the long term effects of virus alone on population trends with the effects that virus plus introduced parasites were shown to have on population trends in New Brunswick (Bird and Elgee, 1957). The virus was introduced into the infestation in 1950 and studies were carried out each year from 1950 to 1959.


1960 ◽  
Vol 92 (8) ◽  
pp. 608-610 ◽  
Author(s):  
C. V. G. Morgan ◽  
A. F. Hedlin

The juniper berry mite, Trisetacus (Eriophyes) quadrisetus (Thomas), was unknown in Canada until 1956, when its occurrence was noted on Rocky Mountain juniper, Juniperus scopulorum Sarg., in the Tzouhalem Indian Reserve near Duncan on Vancouver Island, B.C.; it has not been found elsewhere in the Province (Fig. 1). Material was first submitted to the authors by Mr. W. G. Ziller, Forest Biology Laboratory, Victoria, B.C. Each year almost the entire crop of berries on the only two trees in the area is destroyed by the mite; these trees are 30 and 50 feet high. In 1956 and 1957, no normal berries were observed. In 1959, only four healthy berries were found amongst 715 examined from the two trees. Such a heavy infestation indicates that seed production by these trees was practically eliminated since feeding by the mite destroys the seed.


2010 ◽  
Vol 40 (8) ◽  
pp. 1542-1549 ◽  
Author(s):  
Peter H. Nishimura ◽  
Colin P. Laroque

As many insect outbreak reconstructions are typically based on targeted single-site sampling, researchers have often been limited in their ability to draw conclusions about regional trends as opposed to local trends in the data. The results of this paper demonstrate the value of a systematic sampling design when studying spatio-temporal processes that can vary greatly within large continuous areas of forest. Many single-site research programs have been conducted to reconstruct the history of larch sawfly ( Pristiphora erichsonii Htg.) outbreaks in the eastern boreal region of North America. However, no such research has yet been conducted in the region of Labrador. In an attempt to illustrate the strength of a systematic gridded sampling protocol over a single-site study, we sampled a 12-site grid in western Labrador. Dominant and codominant species were sampled at each grid point, resulting in 24 master chronologies. Six eastern larch ( Larix laricina (Du Roi) K. Koch) chronologies (host) and a regional black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) chronology (nonhost) were used to establish a host–nonhost analysis of past sawfly outbreaks on a regional scale. Both regional and localized larch sawfly outbreaks were identified, but in general, larch sawfly outbreaks in western Labrador appeared to be spatially synchronous and regional in scale.


1960 ◽  
Vol 92 (9) ◽  
pp. 662-667 ◽  
Author(s):  
W. Y. Watson ◽  
G. R. Underwood ◽  
J. Reid

Three known species of scale insects belonging to the genus Matsucoccus occur on pine trees in northeastern North America: M. gallicolis Morr., on pitch pine, Pinus rigida Mill., and scrub pine, Pinus virginiana Mill. (Parr, 1939); M. resinosae Bean and Godwin on red pine, P. resinosa Ait. (Bean and Godwin, 1955); and M. macrocicatrices Richards on eastern white pine, P. strobus L. (Richards, 1960). This last species. in contrast with the others, is closely associated with the fungus Septobasidium pinicola Snell. From 1957 to 1959 personnel of the Forest Insect Laboratory, Sault Ste. Marie, and the Forest Biology Laboratory, Fredericton, collected some 500 specimens from 21 areas in Ontario and the Maritime Provinces. These collections, augmented by herbarium specimens provided by the Forest Pathology Laboratory, Maple, from five other areas in Ontario, not only the insect specimens necessary for the dercription of the species, but information on its biology and distribution.


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