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392 P. D. Syme
Temelucha inlemlptor
(Grav.)
(Hymenoptera:
Ichneumonidae)
ParageroIa nigrifemur
(Ashm.)
(Hymenoptera:
Bethylldae)
throughout the range of European pine shoot moth in Ontario and collections since that
date have confirmed this (Fig. 22). It was also well established throughout Quebec, in the
maritimes, and in Michigan, where it had not been released (Syme 1971).
Since 1968, this parasitoid has become widespread throughout Nova Scotia and
Prince Edward Island and has been found in the southeastern corner of New Brunswick
(L.P. Magasi 1981 personal communication). In Newfoundland it has been recovered
twice, both times at St. John's (A.G. Raske 1981 personal communication). No releases
have ever been made of this parasitoid in either the maritimes or Newfoundland. Thus,
the hypothesis expressed by McGugan & Coppel (1962) and Syme (1971), that the
parasitoid and its host are easily dispersed by planting infested nursery stock, is clearly
reinforced by the events of later years. It is also known that O. obscurator disperses well
on its own, for at Cockburn Island in Lake Huron, where it had been released in 1966
(Syme 1971), it was recovered 5 years later (1971) at Sand Bay, 12 km from the release
point. Here it parasitized 39% of the European pine shoot moth, indicating it had been
present for some years. In 1972 no R. buo[iana could be found at Sand Bay.
In British Columbia, where again no intentional releases have ever been made, O.
obscllrator occurs in the general area of Vancouver-Victoria (C.E. Brown 1981
personal communication) (Fig. 22).
In Ontario, where further studies have been made of the beneficial effects of wild
carrot and other flowering plants on the longevity and increased fecundity of O. obsauator
(Syme 1977), several situations were studied since 1968 that supported this technique of
enhancing parasitoid attack. At one small plantation in Brantford Township, Brant
County, where D. carota was plentiful, O. obscllralor was released during the summer
of 1972. The population was not sampled in 1973 or 1974, but by 1975 parasitism had
risen to 60% and no European pine shoot moth population remained in 1976. In three
other plantations replete with D. carota, parasitism rose to over 50% in 3 to 4 years with
the concurrent demise of the European pine shoot moth population.
It seems apparent that the presence of a suitable source of food in the form of D.
carota can, under otherwise favourable conditions, increase the effectiveness of O.
obscllrator to a level virtually able to eliminate the European pine shoot moth population.
On the basis of these results, workers in Nova Scotia are attempting to establish wild
carrot in pine plantations, but the results are not yet fully known (L.P. Magasi 1981
personal communication).
This primary internal larval parasitoid with cleptoparasitic habits (Syme 1971) has not
been released since 1961. It persists at Elmira, Ontario, where it competes to the
detriment of O. obscllralor. T. interrllptor was virtually always in a host with O. obscllrator,
resulting in the death of the latter. Thus, in a field experiment designed to show the effects
of D. carola, on O. obscllralor at Elmira, from 1966 to 1978, T. interrllptor parasitized up
to 50% of the hosts already attacked by O. obscuralor, preventing the latter from
attaining levels of parasitism over 40% necessary to cause the collapse of host populations.
Thus it confounded the field trial that otherwise showed promise of demonstrating the
beneficial effects of D. carota on O. obscurator.
This external, multivoltine gregarious parasitoid had been found to be very effective
against European pine shoot moth in Argentina (Brewer & Varas 1971). With background
supplied by E.M. deBrewer, Department of Entomology, Cordoba National University,
laboratory tests in Canada (Sault Ste. Marie) demonstrated that P. nigrifemur showed
no tendency to select for hosts parasitized by O. obscllralor. Thus it has no cleptoparasitic
tendencies (Syme 1974). Consequently, on 21 August 1974,695 adults (unsexed)
were released at a site 4.5 km north of Elsinore, Amabel Township, Bruce County,