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Table 86
Open releases and recoveries
Neodiprion sertiler (Geoffr.)
Neodipriol/ satirer (Geoffroy). 335
of parasitoids against the European pine sawfly,
Number Year of
Species and province Year Origin released recovery
Dipriocampe diprioni Ferriere
Ontario 1972 Austria 78
1974 Germany 183 1975
1978 Italy
{
33
Italy
1979 Switzerland
and Austria
272
Exenterus abruptorius Thnb.
Ontario 1972 Austria 648
1973 Austria 1021
1979 Austria 967
1979 Italy 1035
1980 Finland 235
1980 Austria 90
Newfoundland 1980 Finland 75
Lophyroplectus lWeator (Thnb.)
Ontario 1970 Ontario 80 1970
1972 Ontario 2263 1972
Newfoundland 1978 Ontario 306
1979 Ontario 38
1980 Ontario 467
1980 Austria 50
1980 Finland 1
Pleolophus basizonus (Grav.)
Newfoundland 1977 Ontario 1007 1977
1978 Ontario 2104
1979 Ontario 1007
1980 Finland 25
infested with N. sertiler near Williamsford, Ontario. Eggs of N. sertiler were collected
in the release area and examined in the spring of 1962 and spring egg collections were
made annually until 1968 in a population study plot 0.8 km away. No recoveries of the
parasitoid were obtained.
Because the egg stage of N. seniler in Canada was essentially an untapped resource
for biological control. it was decided that more study on European egg parasitoids was
justified in spite of earlier failures. The work was carried out by CIBC European
Laboratory scientists. As a result of this work (Pschorn-Walcher & Eichhorn 1971,
1973) it was found that D. diprioni had a univoltine strain adapted to N. seniler and a
morphologically similar bivoltine strain which occurs rarely in N. sertiler. Earlier
failures may have been the result of using the wrong strain and further work on
introduction. using the univoltine strain, was justified. This work started in 1971 with a
preliminary test which indicated that D. diprioni had attacked Canadian N. sertiler and
had overwintered successfully outdoors near Chatsworth, Ontario.
A release of 32 male and 46 female adults was made in Dufferin County Forest, 5
September 1972 (Table 86). but this area was sprayed inadvertently with a chemical