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Literature Cited
Current approaches to biological control of agricultural insect pests 5
In the last Review, the use of a nematode, DD-136, was reported (Welch 1971)
against several crop pests. This work was not continued although there are still several
avenues to explore. Hopefully this will be done in the future. It will also be noted from
Table 1 that predators were used in only 2 instances - one adventitiously, the other in
a greenhouse situation. Possibly this group is less favored because the members tend
to be less specific than parasitoids. However for reasons considered above, even
relatively small degrees of mortality can effect population reductions on a much larger
scale. But it would also be important to determine if there would be a net increase in pest
mortality or if it would be merely compensatory.
Of the 26 agents used, 11 were by inoculation with parasitoids and 7 by inundation
with pathogens. Inoculations gave high success in 2 cases; others could not be
evaluated as it was too early or recoveries had not yet been made. In contrast, 5 of the
7 pests were controlled well by inundation with pathogens. However this method is
primarily for short-term stage control whereas inoculation of new natural enemies is a
long-term population control measure.
In many cases, establishment of exotic natural enemies may be hampered by the low
numbers available for release e.g. against Adelphocoris lineolatus (Goeze), Phyllotreta
spp., and Thymelicus lineola (Ochs.). Propagation has been difficult or unattainable.
Sometimes mortality has been high in rearing andlor storage. This has required intense
efforts by the CIBC to increase the number of individuals obtained. Some new
techniques have been considered e.g. leaving an area undisturbed on the premise that
parasitoid populations would increase. Increasing host populations by the addition of
their eggs from other areas has also been tried successfully in some cases although the
danger of introducing more virulent strains has restricted the use of this technique.
In addition to the work reported in the following chapters there have been some
minor efforts which did not warrant separate sections. These are as follows: Mantis
religiosa L. ootheca were collected near Belleville, Ontario, in 1971 and 1972 and
released near St. John's, Newfoundland against various grasshopper species (Acrididae);
no recoveries have been recorded (R. Morris, 1981, personal communication).
Coccinella septempunctata L. was found in northern New Jersey, in 1973 apparently
as an adventitious introduction (Angalet & Jacques 1975). They were redistributed to
various states in subsequent years and to Nova Scotia in 1981. The species had been
reported from various parts of Quebec (Larochelle 1979) and was found in New
Brunswick in 1981 (P.W. Schaefer, 1981, personal communication).
As in previous reviews, this publication has been possible only through the cooperation
of those who performed the work. In this part. 28 authors have contributed. Their efforts
are gratefully acknowledged. as well as those of editors and typists who are too numerous
to name individually.
Angalct. G. W.; 1 acquest R.L. (1975) The establishmcnt of Coccinella septempunctata L. in thc continental Unitcd Statcs. USDA Cooperative
Economic Insect Report 25, 883-884.
Kcllchcr. 1.S. (1971) Current approachcs to biological control of agricultural insect pests. In: Biological control programmes against insects
and weeds in Canada 1959-1968. Commonwealth Institute of Biological Control Technical Communication
4.1-3.
Larochellc, A. (1979) Les coleoptercs Coccinellidac du Quebec. Cordulia. Supplement 10. I-Ill.
Wclch. H.E. (1971) Various target species allcmplS with 00-136. In: Biological control programmes against insects and weeds in Canada
1959-1968. Commonwealth Institute of BiologiClll Control TechniCIJI Communication 4. 62-66.