History of Larch Sawfly Outbreaks and their Effect on Tamarack Stands in Manitoba and Saskatchewan

1962 ◽  
Vol 94 (3) ◽  
pp. 242-255 ◽  
Author(s):  
L. D. Nairn ◽  
W. A. Reeks ◽  
F. E. Webb ◽  
V. Hildahl
Keyword(s):  
Life Table ◽  
Annual Reports ◽  
Forest Insect ◽  
Forest Reserve ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
History Of ◽  
Insect Survey

The larch sawfly, Pristiphora erichsonii (Htg.), has been under observation in Manitoba and Saskatchewan since early in the present century. Recorded observations were somewhat fragmentary until 1937; since then systematic and detailed annual reports have been provided by the Forest Insect Survey and since 1948 intensive ecological and life table studies have been conducted by staff of the Winnipeg Laboratory at the Whiteshell Forest Reserve, Manitoba.

Estimation of Parasitism of Larch Sawfly Cocoons by Bessa harveyi Tnsd. in Survey Collections

1959 ◽  
Vol 91 (8) ◽  
pp. 496-500 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice
Keyword(s):  
Forest Insect ◽  
Small Areas ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Insect Survey ◽  
Forest Biology ◽  
Biology Laboratory ◽  
Total Parasitism

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.

An Outbreak of the Larch Sawfly (Pristiphora erichsonii (Htg.)) in the Maritime Provinces (Hymenoptera: Tenthredinidae) and the Role of Parasites in its Control

1954 ◽  
Vol 86 (10) ◽  
pp. 471-480 ◽  
Author(s):  
W. A. Reeks
Keyword(s):  
Prince Edward Island ◽  
Ecological Study ◽  
Maritime Provinces ◽  
Forest Insect ◽  
Staff Members ◽  
The Past ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Insect Survey

At least four outbreaks of the larch sawfly, Pristiphora erichsonii (Htg.), have occurred in the Maritime Provinces within the past 70 years. The first (1) occurred from about 1883 to 1885, the second from about 1906 to 1909 (1), and the third from 1919 to 1927. The last outbreak started in 1933 and ended in 1942. Despite extensive sampling by the Forest Insect Survey from 1943 to 1953, only six samples have been taken during this period in the three Maritime Provinces, and each was an isolated colony. Although an ecological study of the insect was not attempted during the latest outbreak, general observations were made by the writer and other staff members of the Survey. These observations are summarized in the present paper to record the outbreak and some of the factors that contributed to its termination. Another outbreak has persisted in Newfoundland from 1942 and perhaps earlier, but the present discussion is largely confined to events in New Brunswick, Nova Scotia, and Prince Edward Island.

History of the Larch Sawfly, with Notes on Origin and Biology,

1955 ◽  
Vol 87 (3) ◽  
pp. 103-111 ◽  
Author(s):  
H. C. Coppel ◽  
K. Leius
Keyword(s):  
British Columbia ◽  
North America ◽  
Native Species ◽  
Insect Pest ◽  
Forest Insect ◽  
Larch Sawfly ◽  
History Of ◽  
Biological Characters ◽  
The Difference ◽  
Forest Biology

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.

Mortality of Cocoons of the Larch Sawfly, Pristiphora erichsonii (Htg.), in Relation to Distance from Small-Mammal Tunnels

1959 ◽  
Vol 91 (9) ◽  
pp. 535-542 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Forest Reserve ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
The Relationship

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

BESSA SELECTA (MEIGEN) (DIPTERA: TACHINIDAE) AS A PARASITE OF GILPINIA HERCYNIAE (HARTIG) (HYMENOPTERA: DIPRIONIDAE)

1947 ◽  
Vol 79 (5) ◽  
pp. 84-104 ◽  
Author(s):  
L. S. Hawboldt
Keyword(s):  
High Mortality ◽  
Great Difficulty ◽  
Control Factor ◽  
Forest Insect ◽  
Larch Sawfly ◽  
Insect Survey

This project arose out of studies of the European spruce sawfly, Gilpinia hercyniae (Htg.), in connection with the Canadian Forest Insect Survey at the Dominion Entomological Laboratories, Fredericton, N.B. Bessa selecta (Mg.) had been observed as a parasite of the larch sawfly, Pristiphora erichsoni (Htg.), but particular interest was aroused in it as a parasite occurring on the European spruce sawfly. The latter host was frequently found to bear the eggs and integumental funnels of B. selecta. The object was to study its biology and effectivness as a possible control factor of the spruce sawfly. However, great difficulty was experienced in rearing the host due to high mortality caused by disease. Hence the original aims were not attained to the entire satisfaction of the author.

Ecological Life-History of the Larch Sawfly, Pristiphora erichsonii (Htg.) (Hymenoptera: Tenthredinidae), in Manitoba and Saskatchewan

1960 ◽  
Vol 92 (7) ◽  
pp. 500-516 ◽  
Author(s):  
W. J. Turnock
Keyword(s):  
United States ◽  
Life History ◽  
The United States ◽  
Western Montana ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
History Of ◽  
Lake States ◽  
Holarctic Region ◽  
North Western

The larch sawfly is a common defoliator of trees of the genus Larix throughout the Holarctic Region. In North America it has been reported from every province of Canada but in the United States it is confined to the northeastern States, the Lake States, and north-western Montana (Drooz, 1956). The northern limits of distribution have not been determined, but extend as far as 61° N. lat. north of Saskatchewan.

A Sequential Sampling Technique for Surveys of the Larch Sawfly

1958 ◽  
Vol 90 (6) ◽  
pp. 331-338 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice
Keyword(s):  
Sampling Methods ◽  
Population Studies ◽  
Sequential Sampling ◽  
Sampling Technique ◽  
Large Sample Size ◽  
Forest Reserve ◽  
Forest Insects ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

Sequential sampling methods have been developed for population surveys of a number of forest insects (4, 6, 7, 9). These methods permit rapid classification of populations into broad infestation classes with predetermined accuracy and a minimum of sampling, and are useful for mapping and recording widespread infestations.The method of assessing egg populations of the larch sawfly, Pristiphora erichsonii (Htg.), developed by Ives (3) for intensive population studies, was not suitable for surveys because of the large sample size required. A sequential plan for the larch sawfly using hypothetical infestation classes was briefly reviewed by Ives (2). This plan is modified in the present paper in accordance with new data that have accumulated from observations on plots in the Whiteshell Forest Reserve and other stands in Manitoba and Saskatchewan.

Population Dynamics of the Larch Sawfly

1964 ◽  
Vol 96 (1-2) ◽  
pp. 160-161 ◽  
Author(s):  
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Life Table ◽  
Quantitative Methods ◽  
Population Data ◽  
Natural Control ◽  
Mortality Factors ◽  
Ecological Relationships ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

The larch sawfly, Pristiphora erichsonii (Htg.), has been studied in Manitoba for over 50 years, since the first outbreaks led to the introduction of the European parasite, Mesoleius tenthredinis Morley. This parasite was credited with reducing the severity of early outbreaks but when host populations again increased in the early 1940's, it was found that M. tenthredinis was ineffective due to the ability of host larvae to encapsulate parasite eggs. Intensive studies of individual mortality factors were initiated at the Winnipeg Laboratory as staff and facilities were expanded in the late 1940's. Development of the life-table concept of recording population data (Morris and Miller 1954) led to co-ordination of several projects until by 1955 a team of research officers was engaged in comprehensive studies of general ecological relationships, parasitism, vertebrate predation, and the effect of defoliation on host stands. Members of the team currently engaged in population dynamics studies and responsible for this exhibit are: Dr.C. H. Buckner, vertebrate predators; W. G. H. Ives, quantitative methods and natural control; L. D. Nairn, interrelations with host tree; Dr. W. J. Turnock, natural and biological control, bioclimatology. Other Winnipeg officers working on related larch sawfly projects are Dr. R. J. Heron, physiological studies, and J. A. Muldrew, biological control with particular reference to immunity to M. tenthredinis.

Some Ecological Factors Governing Populations of the Larch Sawfly, Pristiphora erichsonii (Htg.)

1951 ◽  
Vol 83 (6) ◽  
pp. 152-156 ◽  
Author(s):  
R. R. Lejeune
Keyword(s):  
Soil Moisture ◽  
Ecological Factors ◽  
Forest Insect ◽  
Environmental Resistance ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Growth Habits ◽  
Resistance Data

Several ecological factors governing populations of the larch sawfly, Pristiphora erichsonii (Htg.), have been studied in Manitoba and Saskatchewan since the present outbreak began about 1939. It soon became clear that soil moisture, parasires and predators, and the growth habits of tamarack were among the most important components of the environmental resistance. Data from ohservations and experiments were gathered by several investigators of the Forest Insect Laboratory, Winnipeg. Manitoba, and are still largely unpublished. In this paper, an attempt is made to appraise the over-all effect of these factors on abundance of the larch sawfly.

Developmental Rates of Larch Sawfly (Pristiphora erichsonii (Htg.)) Larvae in an Insectary and in Field Shelters

1960 ◽  
Vol 92 (9) ◽  
pp. 668-674 ◽  
Author(s):  
W. G. H. Ives
Keyword(s):  
Larval Development ◽  
Life Histories ◽  
Field Data ◽  
Forest Reserve ◽  
Sawfly Larvae ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Developmental Rates

In 1959 a study was conducted in the Whiteshell Forest Reserve, Manitoba, to determine if insectary-reared larch sawfly larvae developed at the same rate as in the field. Data were collected on the rate of frass production in both situations and used as an index of larval development. This was part of a broader study that will be reported on more fully in a later publication, but the immediate results should be of interest to those concerned with studies on ecological life histories of other insects.

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