pdf, 57.71Mb - Entomological Society of Canada

Recommendations
Table 50
Senecio jacobaI'll L. , 199
L. jacobaeae was recovered at the two Prince Edward Island sites in 1982 and 1983
although numbers were low (L.S. Thompson personal communication 1983). Also the
possibility of some root damage from larval feeding was noted in New Brunswick (D.
Finnamore personal communication 1981). Prince Edward Island has a more even
distribution of summer rain than occurs on the south west coast of British Columbia, so
possibly the summers are too moist for the biotype released. Frick & Johnson (1972)
found that the life cycle of the Swiss biotype adapted in the laboratory by a decrease in the
length of the egg diapause. With the beetle's rapid adaptability and the probable wide
genetic variation of the British Columbia population (stock from three sources has been
released there), it should be possible to select an adapted biotype in a field cage and
increase the survivors in the laboratory if the field population falls critically low. The
other alternative is to import beetles from a climate with a similar summer rainfall to
Prince Edward Island, but even so some adaptation would probably be necessary.
(1) The cinnabar moth has reduced the seriousness of tansy ragwort in many areas;
however additional species of biological control agents are needed if a fully satisfactory
level of ragwort control is to be achieved.
(2) The most obvious candidate as a second biological control agent is the beetle
Longilarsils jacobaeae. A biotype of this beetle is now adapted to the southwest coast of
British Columbia and should be distributed to ragwort infestations in the region. Estab-
Open releases and recoveries against Senecio jacobaea L.
Species and release site Year Origin No. Recovered
Long;tarsus jacobaeae (Waterhouse)
British Ollumbia
Vancouver 1971 California ex Italy 100 adults 1974
Vancouver 1973 Switzerland 38 adults
Abbotsford 1971 California ex Italy 400 adults
1972 Lab reared ex California
and England 400 adults
1972 California and England 250 adults
1974 UBC site ex Switzerland 200 adults 1975
Nanaimo 1974 England 92 adults 1976
1976 Oregon ex Italy 1000 adults
Chilliwack 1978 Abbotsford 500 adults 1979
Prince Edward Island
Mt. Herbert 1978 British Columbia 300 adults 1982
Charlottetown 1981 British Columbia ISS adults 1982
New Brunswick
Fredericton 1981 British Columbia 180 adults
Tyrill jacobaeat (L.)
New Brunswick
Sussex 1970 Nova Scotia 1000 larvae 1971
Bathurst 1970 Nova Scotia 1000 larvae 1971
Ontario
Guelph 1979 Nova Scotia 4500 larvae Not recovered
Guelph 1981 Nova Scotia 4500 larvae Not recovered
H)'lemya sm«iella (Meade)
British Ollumbia
Abbotsford 1970 Switzerland 6S adults
453 puparia Not recovered
Prince Edward Island
Charlottetown 1970 Switzerland liS adults Not recovered
Charlottetown 1971 United States liO adults Not recovered