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Pest Status
Background
Releases and Recoveries
Altics csrduorum
Guer. (Coleoptera:
Chrysomelidae)
Chapter 32
Cirsium arvense (L.) Scop., Canada
Thistle (Compositae)
D.P. PESCHKEN
New data have been published on the pest status of Canada thistle, Cirsium arvense (L.)
Scop., since the previous ten year review (Peschken 1971). Thomas (1980) summarized
the abundance of Canada thistle on cultivated land in Canada. This is a particularly
serious weed in the three Prairie Provinces, especially in the black soil zone and in
Manitoba. In this province it ranked fifth and sixth in abundance in 1978 and 1979
respectively; ninth and twelfth in Saskatchewan from 1976 to 1979; and on the average
thirteenth in Alberta from 1973 to 1979. Of their most troublesome weeds, farmers in
Alberta, Saskatchewan, and Manitoba ranked Canada thistle second, fifth, and third
respectively, i.e. considerably higher than the rank based on relative abundance (Thomas
1980). Peschken et al. (1980) estimated the loss in yield of wheat in Saskatchewan based
on the sampling estimate of the density of Canada thistle in wheat fields (Thomas 1976)
and estimates of the reduction in yield of wheat at various density levels of Canada
thistle. Assuming the 10 year average yield of 1607 kg per ha and a price of$14.7 per 100
kg, Saskatchewan farmers lost 24 300 t of wheat or $3 600 000 in the reduction of yield of
wheat alone due to Canada thistle in 1976. The costs of chemical and cultural control of
Canada thistle are high. Thus the total cost of Canada thistle in terms of cost of control
and losses to all crops is a multiple of the $3 600 000 estimated for wheat.
Natural enemies of Canada thistle and the initial stages of the biological control work
were discussed in the previous review (Peschken 1971). Work on the biological control
of Canada thistle has also been done in the United States with Altica carduorum Ouer.
(Coleoptera: Chrysomelidae), Urophora cardui (Diptera: Tephritidae), and Ceutorhynchus
Iitura (Coleoptera: Curculionidae) (Andres 1980, Schaber et al. 1975, Story
1980). The latter species is established in Idaho, South Dakota, and Montana (Julien,
1982). Baker et al. (1972) reported on releases of A. carduorum against Canada thistle in
England. Ward & Pienkowski (1978a, 1978b), working in the state of Virginia, United
States, investigated the biology and mortality of Cassida rubiginosa Muell. (Coleoptera:
Chrysomelidae) which has been accidentally introduced into eastern North America.
One insect was screened but not released. The only confirmed host plant of Tingis
ampliata H.-S., (Heteroptera: Tingidae) in its native habitat in Europe is C. arvense.
However, in the laboratory it developed fertile eggs on several other plants. including
the cultivated globe artichoke (Cynara scolymus L.) and safflower (Carthamus tinctorius
L.). Therefore, T. ampliata was not recommended for release (Peschken 1977).
(a) Ecology
Baker et al. (1972) showed that the development ofthe immature stages of A. carduorultl
is slightly faster at 100% relative humidity (r.h.) than at 97%. At an average temperature
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