Tests of sexual isolation indicate that, in the absence of temporal and spatial isolation, the strict mating behavior of the females and the high sexual aggressiveness of the males of Choristoneura fumiferana (Clem.) would obstruct any inward flow of genes from either C. occidentalis Free, or C. biennis Free. Under these same conditions, however, the two latter species may receive genes from C. fumiferana, since, in tests, their females mated indiscriminately and their males were less aggressive than those of C. fumiferana.

In New Brunswick, Tremex columba (Linnaeus) has a minimum life cycle of 2 years. Adults oviposit most commonly in weakened or injured beech trees (Fagus grandifolia Ehrhart) from about 15 August to 15 October and lay two to five eggs in each oviposition hole. The blackish eggs either hatch in 2–4 weeks or hatch the next May or early June. The larvae tunnel in wood infected with the fungus Daedalea unicolor Buller ex Fries. This fungus is closely associated with each stage of female development. Eggs laid in the absence of the fungus hatch but the larvae do not develop beyond the first instar. T. columba passes the second winter in the larval stage and the adults begin to emerge in August. During each year of observation, males began emerging before females. The emerging females often lay eggs in the galleries and the progenies are male. Three species of Megarhyssa are the chief parasites of T. columba larvae in New Brunswick.

At least seven species of arthropods were found in or associated with leaf galls of the grape phylloxera, Phylloxera vitifoliae (Fitch), on cultivated and wild grapes in Ontario, Leucopis simplex Loew and Lestodiplosis grassator (Fyles) were the most common species. Larvae of both preyed upon eggs of the phylloxera; whether they attacked other stages was not determined, nor was their effect on gall populations. L. grassator occurred almost exclusively on wild grapes; L. simplex was found in galls on both cultivated and wild grapes, associated with all generations of the leaf form of phylloxera. L. simplex was parasitized by Melanips sp. and Lygocerus sp. Another predator, Scymnus cervicalis Muls., occurred rarely. Thrips, mites, and neuropterous larvae were also found occasionally, but predation by these species was not demonstrated.

Ventral nerve cord severence in newly emerged females of Tenebrio molitor L. resulted in a rate of oocyte production significantly higher than in normal, mated females and much higher than in intact virgins. This suggests that some nervous, inhibitory factor normally controls oocyte production. Mating partially suppresses this inhibitory mechanism, but the higher rate of oocyte production in females with severed nerve cords indicates that the inhibitory mechanism is exercising some control over oocyte production at all times. A sequence of events in the control of oocyte production in Tenebrio is proposed.

Female pupae of Malacosoma pluviale (Dyar) treated externally with 80 μl of farnesyl methyl ether during their second day retained most of their original lipid content on the seventh day, when the eggs were maturing. Control pupae lost nearly half their original score in the same interval. In contrast to controls, pupae treated with 40–80 μl (4th–6th days) developed fewer, lighter eggs, and their adults lived longer, were more active, and less inhibited in egg-laying. But the egg masses from treated individuals contained scattered, tumbled eggs and were oversupplied with spumaline.

When eggs were incubated in April, those from individuals treated with ≥ 40 µl failed to hatch. Eggs from females that had received < 40 μl hatched, bur the resulting colonies died before their second instar in their normal habitat, whereas control colonies survived. Hatching of treated stock could be induced by premature incubation in January, but the numbers and quality of the emerging larvae were greatly reduced in comparison with controls.

The results provide further evidence that behavioral types in M. pluviale are mainly nutritional products. Because of the treatment, developing eggs were deprived of nutrients during the pupal stage and developing adult tissues were oversupplied. Farnesyl methyl ether may have exerted its effect by acting like an excess of juvenile hormone during that part of the pupal stage in which the normal level of activity of the true juvenile hormone is thought to be very low.

Field evidence suggests that an equivalent humoral imbalance sometimes may occur naturally, and thus affect a generation's reproductive capacity, especially near a peak in abundance. Hormonal mimics therefore might be used to manipulate pest populations, but this suggestion includes a cautionary note.

Many of the small leafhoppers that feed and reproduce upon the foliage of birch trees belong to the subfamily Typhlocybinae. The main species are Typhlocyba hockingensis Knull, T. pomaria McAtee, Ribautiana foliosa (Knull), Edwardsiana bergmani (Tullgren), Empoa latifasciata Christian, Dikrella cruentata (Gillette), Alebra albostriella (Fallen) and several Erythroneura species. Their ecological requirements and life histories are described. Notes on morphology and illustrations of each species except the Erythroneura are included.

The adults, mummies, and final-instar larvae of the eight hymenopterous parasites of the pea aphid, Acyrthosiphon pisum (Harris), in Eastern Canada are described and illustrated. The history, synonymy, and biology of each species, and the problems of species differentiation in two of the genera, Aphidius and Praon, are discussed. Keys are given to separate the adults, mummies, and cast skins of the last larval instar.

Larvae of Hyphantria cunea Drury were reared on early, mid-season, and late foliage collected from the same apple trees. Survival was significantly lower on late foliage and the fecundity of the moths decreased from 604 in the early series to 128 in the late. Half the filial generation was reared under nutritional stress on a deficient synthetic diet and the other half on a very favorable host, speckled alder. Under both conditions there was a strong transmitted influence of parental food quality on the viability of the eggs and on the ability of first-instar larvae to become established on food. The progeny of the late series did not survive beyond this instar. When the filial generation was subjected to nutritional stress, the influence of parental food was apparent throughout the larval, pupal and adult stages, with progeny of the early series having higher survival than those of the mid-season series. However, when the filial generation hail very favorable food, there was no significant difference in survival rates subsequent to the larval establishment period.

The quality of foliage available to univoltine populations of H. cunea depends largely on temperature. Thus, in the development of population models for this species, temperature should be treated as a variable having not only direct effects on establishment and survival each season, but also indirect effects on the quality of the progeny in the following season.

Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., broods developed more rapidly at a constant 21 °C. than at 13 °C. or at the temperature outdoors during the summer. The dry weight and fat content of young larvae developed at 13 °C. were lowest, whereas the dry weight and fat content of adults reared at 13 °C. were highest. Adults reared outdoors had the lowest dry weight and fat content. The differences in weight and accumulated fat are attributed to the effect of temperature on the length of time available for feeding, and on the rate of metabolism in the various developmental stages. Variations in temperature during the prediapause–diapause period also produce changes in the relation between the size and fat content of the adults.

The suitability of a European moth Anaitis plagiata (L.) for the biological control of the weed Hypericum perforatum L. in British Columbia is evaluated. It is concluded that the introduction of the moth is justified as it offers prospects of reducing the weed density without damage to economic plants. A. plagiata is preadapted to dry habitats and ecologically restricted to them. Its high fecundity and two generations a year should enable it to reach an effective population level rapidly and the early spring feeding by the overwintered larvae should damage the weed when it is most vulnerable. It was shown by feeding tests that the larvae are restricted to plants in the genus Hypericum. Furthermore, all the known hosts of the genus Anaitis are restricted to the genus Hypericum which indicates that the insect-host plant relationship is an old and highly stable one. Larval feeding was found to be partly in response to a chemical compound present in the cuticular waxes of the host plant.

The pine seedworm, Laspeyresia piperana (Kft.), is a common pest in cones of Pinus ponderosa Laws. in British Columbia and may destroy up to 50% of the seed.

Moths emerge in May, mate, and lay eggs on second-year pine cones. Immediately after hatching, the larvae migrate to the centre of the cone and feed on seeds throughout the summer. In autumn, larvae tunnel into the cone axis to overwinter. Pupation occurs in spring.

Ovex, tetradifon, and chlorbenside which are largely innocuous, and parathion which is more harmful, to beneficial insects and predaceous mites, have been used in apple orchards in Nova Scotia to control outbreaks of phytophagous mites. Dicofol is used at present but it is toxic to predaceous mites. Animert V-101 is effective against Panonychus ulmi (Koch) but is ineffective on most beneficial species. Dicofol and Animert V-101 initially reduced a high population of P. ulmi but were equally ineffective on predaceous insects. The latter chemical was innocuous to Typhlodromus pyri Scheuten and Vasates schlechtendali (Nal.) but gave partial control of P. ulmi. A similar high population of P. ulmi was reduced to a low level on a comparative untreated plot where a high number of predators was present. This reduction was evident 1 month later than on the treated plots. The overwintering numbers of P. ulmi in 1966 were below a commercially tolerable level on the three plots.

The use of false-underground hives (surface hives with tunnels attached to their entrances) when and where the desired species of bumblebees were common made the task of obtaining colonies for pollination purposes comparatively easy. False-underground hives were much less costly to set out than underground hives and attracted many more queens of surface-nesting and versatile species, as well as underground-nesting species, than did surface hives. Apparently the surface-nesting species will accept a nest that is entered through an upward-sloping tunnel but not one that must be reached through a downward-sloping tunnel; underground-nesting species require a tunnel but are not influenced by the direction of its slope.

Setting occupied hives on posts with moats protected the queens or their broods from flooding, ants, ground squirrels, skunks, mice, shrews, and ungulates, but not from Psithyrus, even when odoriferous substances were put in the moats to mask the odor of the broods.

The viral activity of soil treated with polyhedra of the cabbage looper, Trichoplusia ni (Hübner), was determined at intervals by bioassay. Soil in plots treated in 1961 at a rate of 6.4 × 1010 polyhedra per square meter of surface contained about 25% of the original infective virus more than 5 years after treatment. A similar rate of decline in viral activity occurred in plots treated with polyhedra in 1963. Viral activity of soil retained under artificial conditions decreased more rapidly.

Field and laboratory tests showed that foliage of cruciferous plants grown in soil treated with polyhedra was contaminated with the virus, probably largely by virus-laden soil being splashed onto foliage by rain.

An account is given of the development of a spray nozzle consisting of three steel hypodermic needles coaxially arranged to form three concentric tubes. Air from the inner passage and outer annular orifice atomizes the liquid issuing from the intermediate annular orifice. The resultant effect is an improved control over spray breakup and deposit. A description of the nozzle, its performance characteristics and some application to the study of insect toxicology are presented.

The newly named C. biennis has a two-year cycle characterized by a second period of diapause at the end of the third instar. Second diapause occurs to varying degrees in C. fumiferana, C. occidentalis, C. orae, C. pinus pinus, and many of their hybrids, but has not been recorded in C. viridis. Although the incidence of second diapause can be influenced by the length of photoperiod to which larvae are exposed after completion of the second-instar diapause, second diapause occurring naturally is not primarily under environmental control. Laboratory studies have demonstrated differences in the incidence of second diapause manifested by these species and by some of their hybrids that point to the existence of genetic differences between them. This evidence supports the newly gained taxonomic status of these insects.

Laboratory tests of heat tolerance of last-instar larvae of the larch sawfly, Pristiphora erichsonii (Htg.), were made to provide information for the evaluation of the role of high temperature as a mortality factor in field populations.

Test larvae were reared from eggs at 21 ± 1.5 °C and 50 ± 10% relative humidity. LT50's were determined at 37°, 39°, 40°, and 41 °C for larvae conditioned at 30 °C and 75% relative humidity.

Larvae were less heat resistant during the first 24 hours after molting than they were 24 to 48 hours after molting. The conditioning temperature and the duration of conditioning had very significant effects on heat tolerance. Differences in acclimation due to heat treatment could not be accounted for by differences in free water content.

Temperature acclimation will occur in field populations and must be considered in evaluating the role of high temperature as a natural mortality factor.

Larvae may encounter lethal temperatures when wandering on branches or tree trunks or crawling on dry ground in open sunshine.

The optimum temperature for rate of development and survival of immature stages of Coccinella novemnotata Herbst was found to lie between 70° and 80°F. Different photoperiods between 10 and 18 hours per day did not influence rate of development or survival. With a 16-hour photoperiod the mean number of eggs laid per female and mean longevity of females were greater at 70° than at 80°F, but not significantly so. At 90°F egg production was sharply curtailed and most eggs produced were infertile, probably due to inactivation of sperm in the male. Photoperiods of 10, 12, and 18 hours per day induced diapause in a large percentage of adult females; intermediate photoperiods of 14 and 16 hours per day were much less effective. Low temperature and lesser amounts of food available to adult females increased the effectiveness of the short and the long photoperiods for inducing diapause. The stage susceptible to induction of diapause, or conversely the initiation of gonad maturation, was determined to be the young adult from emergence to 7 days of age. The results of experimental data are related to a field study of the biology of this insect in California.

None of the saturated C6–C14 fatty acids fed free as components of a chemically-defined diet to larvae of Pseudosarcophaga affinis Auct. nec Fallén (Diptera: Sarcophagidae) improved the rate of growth and development, but several were toxic. In descending order of toxicity, the fatty acids were capric (C10), caprylic (C8), caproic (C6), and lauric (C12); myristic (C14) had no apparent effect. The ED50 was 0.00025 M of capric acid, 0.054 M of caprytic acid, and 0.155 M of caproic acid, respectively. Even at 2.5% of the diet lauric acid was not very toxic. The effects of fatty acids on P. afjinis are similar to those on other insects, though the order and degree of toxicity varied in some cases. Of course, certain fatty acids were widely used as insecticides: their activities varied with molecular configuration and physical–chemical properties. Present insight, however, is that certain fatty acids when eaten may be beneficial to some species and harmless or injurious to others. This suggests that perhaps fatty acids may be useful selective insecticides or substitutes for more dangerous chemicals.

In feeding tests with 20 different dry foodstuffs, some, usually those of high carbohydrate content, permitted Tribolium confusum jacquelin du Val to survive and develop reasonably well. Differences between the sugar content of Sugar Pops and Corn Flakes were probably the reason for better growth on the former than on the latter. Moreover, raisins and bran, i.e. Raisin Bran, was a better food than Bran Flakes. The hygroscopic properties of dehydrated peaches and of pineapple juice soon rendered them unfit as food for T. confusum. It is apparent that though some modern dry foodstuffs that lend themselves well as stored products may be highly susceptible to insect attack, others seem to be “self-protected” from serious insect infestation. This suggests that stored food products might be packaged and handled selectively according to their susceptibility rating and so result in obvious economies in their handling.