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PfeoIopbus ba9zonus
(Grav.)
(Hymenoptera:
Ichneumonidae)
Pathogens
Table 88
Neotiipriol/ .f(°r/iler (Geoffroy), 337
Laboratory and field cane studies of parasitoids against the European pine sawfly
Neodiprion seniler (Geo r.)
Species and province Year Origin Number
Dipriocampe diprioni Ferriere
Ontario 1970 Austria 196
1971 Austria 228
1974 Germany 73
1975 Austria 19
1976 Switzerland 136
1977 Switzerland 72
£Xenlerus abruplorius Thnb. 1969 Austria 579
Ontario 1970 Austria 244
1978 Austria 242
1978
1978
Germany
Germany { Austria
64
75
1978 Italy 211
1979 Finland 139
As stated earlier, shipments of parasitoids to Newfoundland were started soon after it
was known that N. senifer was established there. The first species to be shipped was P.
basizonus, a multivoltine parasitoid of cocooned pre-pupae successfully introduced from
Europe in the 19305 (McGugan & Coppell962). N. seniler cocoons containing developing P.
basizonus were shipped to Newfoundland in the summer of 1977. They were obtained
from a rearing programme conducted in Sault Ste. Marie, Ontario, during the winter
preceding shipment, and were reared in St. John's. Emerging parasitoids were released
twice weekly between 21 July and 15 August at Windsor Lake, 9.7 km from St. John's. A
total of 631 males and 376 females was released in an infested plantation of mixed jack
pine and Scots pine (Otvos & Griffiths 1979) (Table 86). Approximately 130 adult P.
basizonus were recovered from 600 N. seniler cocoons "planted" in the release area in
the summer of 1977, indicating that the released adults had attacked successfully in
the field (Otvos & Griffiths 1979). Further releases of large numbers of this parasitoid
obtained from rearings in Sault Ste. Marie were made in 1978 and 1979. A small number
of adults from Finland was also released in 1980 (Table 86). There have been no further
recoveries of adults of this species from field-collected cocoons to date. Monitoring of
this release is continuing.
In Ontario, European pine sawfly NPV was extensively used in the 19505 and 1960s by
Christmas tree growers and provincial government forestry officials.
There are several methods of producing this virus in host insect larvae, the simplest
and cheapest being to do so in the field. Plantations with a suitable insect population
density are found and fourth-instar larvae are sprayed using a mist blower to disseminate
NPV at a concentration of 10" PIB/ml. The first dead larvae are found about 7 days after
spraying and colonies of dead and dying larvae are collected daily until about 14 days
after spraying. Larvae are removed from the foliage, frozen, lyophilized, ground to a
fine powder, and the concentration of PIB per gramme determined. About lOS PIB are
obtained from one dead larva, so, using a dosage of 5 x 10" PIBlha. about 50 virus-killed
larvae are required. A virus treatment is therefore very economical. Between 1970 and
1975 a considerable quantity of this virus was produced by Ontario Ministry of Natural