An outbreak of needle miner on lodgepole pine occurred in the late 1940's, decreased to low levels in the 1950's. but increased aeain recently. In both outbreaks, populations were highest in a band along the middle of the slopes of the valleys.

The moths are crepuscular with most of the flight, feeding, and laying activities taking place at sundown. Temperatures and wind at this time are critical for these activities. Low temperatures and wind which are more common at higher elevations probably reduce oviposition rates. Some downward drift of the moths also probably takes place making the rate of increase through the adult and egg stages much higher at valley bottom than further up the slope.

For the past forty years there have been virtually no introductions of honeybee stock from foreign countries into Canada or the United States. This has been due to the stringent restrictions on importing honeybees which have been in force since 1922, as a safeguard against the introduction of acarine disease. The mite which is responsible for the disease, Acarapis woodi, is present in many parts of Europe, and has also been reported from Asia, Africa and South America. It has not so far been found in North America, although external mites of the same genus (A. dorsalis and A. externus) are now known to occur fairly commonly throughout Canada and the United States.

Heterogenetic holocyclic species in Adelgidae consist of the five generations: sexuales (♂, ♀), fundatrix (F), alata-migrans (M), hiemosistens (H), alata- remigrans or sexupara (R), of which the (♂, ♀) and (F) live on the primary host (Pinaceae: Picea), (H) on the secondary host (Pinaceae: Pinus, Abies, Tsuga, Pseudotsuga or Larix), and the two winged generations (M) and (R) maintain the migration cycle from and to the other host. The range of such a species is controlled by the occurrence together of both the primary and the secondary host. It seems that the evolution of the Aldelgidae has been closely associated with the phylogeny and distribution of the conifer-family Pinaceae, and that speciation of the parasite has followed the speciation of the host plant.

Conventional and modified methods of obtaining supercooling points of immature stages of insects have been utilized in studies of the cold-hardiness of the European pine shoot moth and the European pinesawfly. A method has been developed to permit visual observation of the freezing process of more than one specimen at a time. A freezing chamber consisting of a hole one inch in depth and one-half inch in diameter is located in the upper end of an aluminum rod partially submerged in a dry ice-alcohol mixture. A small filter paper disc, used as the insect platform, rests upon a #40 copper-constantan thermocouple located near the base of the freezing chamber. The thermocouple enters the chamber through a hole in the wall after several circuits around the circumference of the rod to prevent temperature anomalies attributable to thermal conduction within the wire. The thermocouple is connected to a sensitive recording potentiometer. The wall of the freezing chamber is blackened to prevent reflection of light from obscuring the view of the freezing process, through a binocular microscope mounted above the freezing chamber. The moment of freezing is readily recorded on the temperature trace provided by the potentiometer. At a cooling rate of approximately 5°F. per minute, a correction factor of 2.5°F. must be added to the indicated freezing point to obtain the actual temperature at the surface of the platform. When this correction is applied, the results provide data applicable to statistical analysis of freezing point determinations.

Relatively little is known of the life history, ecology and behaviour of most species of Tabanidae. Knowledge of their immature stages is particularly deficient. The larvae of only 46, or about ⅛, of the North American species have been described and many of these descriptions are inadequate. The present research was initiated in 1960 to describe and classify tabanid larvae and to contribute information on larval habitats and life histories.

The larch sawfly, Pristiphora erichsonii (Htg.), has been studied in Manitoba for over 50 years, since the first outbreaks led to the introduction of the European parasite, Mesoleius tenthredinis Morley. This parasite was credited with reducing the severity of early outbreaks but when host populations again increased in the early 1940's, it was found that M. tenthredinis was ineffective due to the ability of host larvae to encapsulate parasite eggs. Intensive studies of individual mortality factors were initiated at the Winnipeg Laboratory as staff and facilities were expanded in the late 1940's. Development of the life-table concept of recording population data (Morris and Miller 1954) led to co-ordination of several projects until by 1955 a team of research officers was engaged in comprehensive studies of general ecological relationships, parasitism, vertebrate predation, and the effect of defoliation on host stands. Members of the team currently engaged in population dynamics studies and responsible for this exhibit are: Dr.C. H. Buckner, vertebrate predators; W. G. H. Ives, quantitative methods and natural control; L. D. Nairn, interrelations with host tree; Dr. W. J. Turnock, natural and biological control, bioclimatology. Other Winnipeg officers working on related larch sawfly projects are Dr. R. J. Heron, physiological studies, and J. A. Muldrew, biological control with particular reference to immunity to M. tenthredinis.

Preliminary observations show that the pigmentation of eggs and other tissues in conifer sawflies is a valuable taxonomic criterion when the colour can be described objectively in such a way as to allow mathematical analysis of the data. Reproducible semi-integral attenuance spectra covering the spectrsl range 30 kc./cm. to 13 kc./cm. are obtained usins Shibata's opal glass technique for the examination of translucent material. Tfiese spectra are plotted as the log of the semi-integral attenuance and analyzed both qualitatively for positions of maxima and minima, and quantitatively for the relative attenuance level at given spectral positions. The homogeneity of quantitative data from different samples is tested graphically by the triangular co-ordinate method.

One of the outstanding problems now involving North American Trichoptera is that about 80% of the species are still totally unknown in the immature stages. As in many other insect groups, most initial work has been concerned with species differentiation, classification and distribution, and has dealt largely with adults. There are now about 1000 species of caddisflies known from Canada and the United States, but larvae, the best known of the immature stages, have been described for only about 190 of them. Lack of information concerning larvae is especially conspicnous in the Limnephilidae, our largest family, where this stage is known in only about one-half of the genera. Although inadequate knowledge about the immature stages of insects is not uncommon there are, for the study of Trichoptera, several reasons why much could be gained by overcoming it.

In wireworms most of the sensory nerve system terminates peripherally in seven types and 20 sub-types of sense organs. All are represented in the head and its appendages. The main types of sensilla are thick-walled hair, campaniform, mandibular pore canal, scolopophorous, peg or thin-walled hair, and sensory plate organs, and a large antennal sensory appendix. The first three types are innervated by one, the fourth by two, the fifth and sixth by four, and the last by more than four neurones.

Introgressive hybridization, the feeding back of alien genes from an invading species into a resident population, has not been widely studied in animals. Conclusions favouring its occurrence are mostly founded on comparative studies of external morphology: since parallel selection of similar gene allels would provide the same end result, such conclusions are open to question. White's arguments against introgression as the cause of overlapping phenotypes in Austroicetes grasshoppers, on the other hand, carry conviction because they are based on comparative internal morphology – on cytological study: the two supposedly interbreeding species were found to differ in several chromosomal diagnostics, to the complete absence of intermediates.

The development of the Manitoba Horse Fly Trap was motivated initially by the need to control tabanid flies in spite of a lack of effective and safe insecticides. This objective could be realized only through a study of orientation behaviour in the field. Starting with the old observation that tabanids are attracted to darkcoloured objects (‘targets’), the influence of colour of target, colour of background, size, shape and movement of target were investigated. The most attractive target proved to be a glossy black (or red) sphere about 24 inches diameter, about three feet above the ground. In the course of its development the trap has provided interesting insights into visual perception of tabanids which will require physiological confirmation. The attractant principle is overwhelmingly visual. An initial surmise that thermal radiation contributes to the attraction significantly has been superseded, although a thermal stimulus may be involved in the behaviour of the flies after they reach the trap. Since only the hemato- phagous sex (females) is attracted to the trap, the behaviour involved appears to be teleologically related to host seeking activity. On arrival at the trap the insects fly in the space around the target and eventually move upward into the no-return chamber at the apex. When the trap is used for fly control the apical chamber is not needed if the interior of the trap is treated with a powerful, residual insecticide. In addition to its potential uses in conjunction with insecticides for control of tabanids, the Manitoba Horse Fly Trap can be used to study the correlation of flight activity with meteorological conditions as well as the seasonal and geographical distribution of tabanid species. The trap can be used effectively in the study of Stomoxys behaviour and control. If the sphere is replaced by a wick containing organic sulfides, blow flies can be attracted to it in considerable numbers.

During the past 100 years, insect control has been a predominant objective and influence on the development of entomology in Canada. Preoccupation with the insecticide method of insect control threatened for a while to divert entomologists from the biological bases of their science. But the scientific questions and practical problems raised by insecticides have recently generated a renaissance of biological thinking about insects and ways to control them. Older biological methods and certain promising new ones are receiving increased attention. Insecticides have won a permanent place in our arsenal but we can no longer continue to rely so heavily on this one weapon. A new perspective is emerging in which strategies of insect control will be formulated on the basis of population dynamics studies and will involve assembling from a variety of control methods the appropriate combinations to meet particular problems. The requirements of these combined strategies will impinge increasingly on economic and social affairs which, in turn, will modify the technology of insect control.

Chlorinated hydrocarbon insecticides and notably DDT have provided means of effectively controlling mosquitoes, blackflies and insects of medical importance not only in Canada but elsewhere, and of eradicating the transmission of malaria by anophelines, the world programme for which is already successfully half completed. However resistance has developed to these insecticides in 80 species of public-health importance, including 3 in Canada. Basic studies on the physiological mechanism and mode of inheritance of resistance in Culicine mosquitoes are being performed in Canada. Among insects and mites of agricultural importance, 14 species have developed resistance in Canada, and a world total of 77. Basic studies on the mode of inheritance of cyclodiene-resistance in root maggots are being undertaken in Canada. Countermeasures against resistance include the use of synergists, non-detoxicatable analogues, and negatively-correlated compounds. Resistance usually dictates a shift from the chlorinated-hydrocarbon to the organophosphorus insectices, thus reducing the residue problem, particularly for wildlife. Alternative methods of control include the sterile-male technique, with 2 successful examples but no success yet with mosquitoes, and the use of chemosterilants, with an example of imminent success against houseflies on islands. Chemosterilants however, like bacterial toxins, are not free from the possible development of resistance by detoxication.

The background against which decisions on control strategy and tactics are made is explained and general approaches to pest control are discussed at length. Canadian work on population dynamics that involves research on the processes that regulate numbers is reviewed. The author's conviction that this work provides the best avenue yet explored to the solution rather than temporary alleviation of pest problems is explained. A pest-control strategy for the insects attacking peach in the Niagara Peninsula, in which a logical progression of research, the assignment of priorities, and the concentration of staff and facilities on problems of major importance are advocated, is outlined. Finally, weaknesses in administrative strategy are discussed and it is suggested that the findings of basic researchers on population dynamics should be exploited more fully by parent organizations and applied more energetically by those directly charged with responsibility for insect control.

A computer program has been developed for use in evaluating various strategies of insect pest control. At its present stage of development, the program simulates the effects of various dosages of insecticide, parasite release, and spraying of virus, or any combination of these, weather and pest density on reproduction, dispersal and mortality in a pest population. Effects of changing pest densities on the parasite population and on tree growth and mortality in a hypothetical, 6.4 million-acre balsam fir forest are simulated. Also, the computer simulates dispersal of parasites and disease incidence. All computations are performed separately for each of 625 4-mile-by-4-milc hypothetical squares of forest area in the hypothetical 10,000 square mile area. All operating costs and losses due to lost tree growth and tree mortality are printed each year. The particular set of strategies to be used in each game is included in the input data for each 35-year computer experiment, along with data on physiological parameters, allowable pest thresholds for each type of control, genetic parameters, behavioristic and dispersal data and costs of control. One play of the game takes 50-120 seconds on an IBM 7090 computer, depending on the array of strategies selected.

There were a number of significant conclusions from the simulation study. Biological control agents can not be as effective as insecticides unless they keep the pest at very low levels indefinitely. If they only drop the pest to about 10% of the peak level it would have attained without control, this may not be good enough to save the trees, because lethal effects accumulate. That is, pest densities which are not quite high enough to kill a tree quickly can kill it if the pest persists at these densities for several consecutive years. However, by selecting biological control agents with optimal physiological parameters, biological control can be made to produce totally effective control.

For all kinds of control, control is vastly more effective if applied 10 years or more before peak pest densities. Therefore, potential pests should be subjected to preventive control at pre-pest densities, rather than being allowed to reach critical densities. The latter policy ignores the hazard of successive years of sublethal pest densities whose effects can cumulate to become lethal. It should be noted, however, that this conclusion follows from exploration of a hypothetical situation, and might not be applicable when considered relative to the exigencies of an actual field problem.

The decision-making process in insect control at the practical level involves not only the complex relationships between pests and their environment, but also equally complex human relationships and values. The actions advantageous to one of our resources may be harmful to another. Ultimately, the process of decision-making, at the individual problem level, must be integrated with economic factors, public health and sociological considerations. Calculated risks must be taken, but decision-making should he based on the evaluation of data bearing on efficiency, economy and safety of use of any method, including pesticides. Integrated control as a newly repopularized concept is examined in relation to the economics of its potential application in Canada. The concept of safety of pesticide residues in food is discussed and related to “good agricultural practices.” Three operative levels of decision-making are examined; the regulatory, quarantine and pest suppression activities and the role of the local advisory committees on pest control. The author expresses concern that the current public preoccupation with establishing safeguards for pesticide use does not begin and end merely with legislative action and strengthening of enforcement agencies. A desirable parallel result likely to be overlooked would be administrative and financial support for research on how the use of pesticides may be developed in the best interests of the community as a whole.

The Canadian program in insect pathology is reviewed in general terms. The pathogens that have been studied include viruses, fungi, bacteria, protozoans and nematodes. Many aspects of the various host-parasite relationships have been investigated under field and laboratory conditions.

Some recent developments on aphid digestive enzymes, aphid feeding and nutrition on host-plants, and on artificial media are briefly reviewed. A chemically defined diet, on which pea aphid life and reproduction can be sustained during two successive generations, is described. An important feature of this successful chemical diet concerns its amino acid composition, which was based on that of pea aphid blood and honeydew. An artificial feeding method for aphids divorced from their host-plants should prove a valuable tool in the study of the nutritional requirements and the intermediary metabolism of these insects, as well as in determining the influence of dietary constituents on polymorphism and in relation to the phenomena of plant resistance to aphids.

The number and kinds of courses in Entomology at Canadian Universities are briefly described. There is a discussion of two approaches to the undergraduate degree: one, the broad approach, where only one course in a specialty is taught but many disciplines are covered, and two, the narrower approach, where many courses in the specialty are given.

The author favours the broad approach. Biologists should be produced first and Entomologists second. There is some question as to whether, at the Universities, Entomologists, in the narrow sense, should be produced at all.

The argument for graduate training in biological disciplines instead of training in specialized groups of animals is presented. Also the question is raised of where, and how, graduate training should be done. It is concluded that graduate training is best done in the biological disciplines, that it should be directed by the Universities, not by off-campus laboratories and that it should be done in a manner decided by the Universities.

The reason control measures are applied is to reduce the harm caused by pests. “Pests” is a subjective word that is arbitrarily used to refer to some of the living organisms that harm man and his property. Pest control measures may be classified on any of several bases, bur any one classification that uses several bases is liable to cause misunderstandings. Biological controls are the use by man of living organisms to control pest damage. Approaches to biological control are illustrated by results of work on four pests found in Ontario. These results also illustrate how insects may be interrelated through natural enemies that they have in common. As far as possible control measures should be selective for pests, or pest and other non-beneficial, species only. Biological controls tend to be relatively more selective than other, comparable, control measures. They are also the most feasible existing way of keeping pest damage down without continuing human intervention. Increasing attempts to erase pest problems, rather than to alleviate pest attacks temporarily, may result in increased Government participation in and regulation of pest control programmes.