The mean post-mating age of mated female moths of the European corn borer, Ostrinia nubilalis (Hübner), from light traps varied from 3.4 to 5.2 days during the June–September flight period at Harrow, Ontario, in a manner consistent with assignment of moths to 3 generations per year. At the beginning of the first generation the mean age was 3.66 days and rose to 5.21 before flights ceased. At the beginning of the second generation the mean age was 3.39 days and rose to 4.47 days. A third generation could be detected in early September by a significant drop in age and an increase in virgin females. The average age of mated females was negatively correlated with the proportion of virgin females in the same week (r = −0.648, P = 0.02), indicating that about 40% of the variance in age of mated females was associated with emergence of new recruits to the population. Females collected with a sweep net from their day time resting places in weeds were either the same age or older than those from the light trap. The mean age of moths from light traps was found to be not meaningful when it was tested as a factor in forecasting damage caused by their progeny in green peppers 3–5 weeks later.

The effects of the major factors on populations of the wheat stem sawfly, Cephus cinctus Norton, were studied in the field at Lethbridge, Alberta between 1970 and 1977. Fecundity of the females, which contain an average of 32.7 eggs, is influenced by the condition and variety of host plants in which they develop as larvae. Populations of the adults that emerge from infested crops cut 7–9% by the larvae in one year may infest 70–80% of the stems of adjacent crops in the following year. Increased adult densities, however, fail to increase markedly the percentage of stems infested because the adults concentrate at field margins when they reinfest the most preferred stems. Because only one larva can mature in each stem, competition within stems that receive more than one egg causes a major drop in the population but not in the percentage of infested stems cut. Another major drop is caused by host plant resistance, which is influenced in both susceptible and resistant wheats by the weather during the growing season. On an average, all of the larvae die in 28% of the infested stems of two susceptible wheats and in 67% of those of a resistant wheat. The mortality in resistant wheats, however, is generally not sufficient to prevent economic infestations in subsequent years. Parasitism, which was a major factor in only 7 of 36 years in southern Alberta, is increased by weather conditions that cause delayed ripening of the wheat crops. The mortality of mature larvae and pupae averaged 21.3%. It is affected by extremes of moisture and temperature and can be increased slightly by shallow tillage of infested stubble.

Five trap designs were evaluated for sampling the insect complex attracted to severed shortleaf (Pinus echinata Mill.), Virginia (P. virginiana Mill.), and loblolly (P. taeda L.) pines. The baffled flight trap was superior for capturing Coleoptera. Plexiglas®, saran screen, and 4-directional Plexiglas traps were most efficient in trapping Diptera and Hymenoptera. The results indicate that the choice of any particular trap depends on the group of insects to be sampled.

The accumulation of monoterpenes during the defensive response by grand fir was quantified over a 28-day period. Monoterpene content increased exponentially with time and varied greatly among trees. Following analysis, sampled trees were observed for 4 years. Those trees which showed an extensive accumulation of monoterpenes in response to artificial inoculation with fungi transmitted by the fir engraver were less likely to be killed during this period than trees which exhibited low levels of secondary monoterpene accumulation. The extent of the defensive response was influenced by host age, disease, crown class, and artificial stress. Following inoculation with fungi transmitted by the fir engraver, the proportions of limonene, myrcene, and Δ-3-carene, present in the monoterpene fraction increased. In previously reported laboratory bioassays, each of these compounds has demonstrated higher toxic or repellent properties, or both, than have the other monoterpenes present in grand fir. Mechanical injury resulted in less pronounced reactions than did fungal inoculation. Necrotic lesion formation is accompanied by an increased concentration of short-chain hydrocarbons, followed by a decline to normal levels. Necrotic lesion formation and monoterpene synthesis represent at least two independent activities during the wound response.

In this paper a process-oriented model of spruce budworm phenology is developed which produces simulations comparing favorably with observed phenological trends taken from literature. Major features of this model include: (1) non-linear descriptions of temperature-dependent development of larval instars and pupal stadium; (2) three sources of variability in development rates (intrinsic, sex-related, and microclimatic); and (3) generation of daily temperature cycles for four microhabitats from input min-max air temperature data.

The costs and benefits of insecticidal control and the losses attributable to flea beetle damage are estimated for oilseed rapes in Canada. Analyses of two farm surveys and reports on the efficacies of the various control practices conducted in test plots led us to calculate three sets of estimates based on different assumptions. Four-fold differences are observed between the lowest and highest estimates. The lowest estimates are adopted as the most realistic. The estimated losses were $72 million in 1979, 8% of the annual production. In 1979 growers spent about $12 million on insecticidal control which saved about $44 million worth of production. We conclude that flea beetle damage to rape causes an average annual yield loss of about 10% and is higher in Manitoba than Saskatchewan. The damage levels estimated from small test plots are higher, on average, than those in commercial fields, which accounts for most of the differences among estimates.

The formerly monotypic genus Halidayina Duda, based on the Holarctic species H. spinipennis (Haliday) is revised. Two new species are described, H. exserta from Arizona and California, and H. asymmetrica from Mexico.

A generic description of the larvae of Pagastia Oliver is presented. The larvae of three Nearctic species, P. partica (Roback), P. sequax (Garrett), and P. sp. A are described. A diagnostic key to these species is included.

Three new oribatid mites, Niphocepheus aborigensis n. sp. (Niphocepheidae), Proteremaeus macleani n. sp. (Eremaeidae), and Asperemaeus longipilus n. gen., n. sp. (Eremaeidae), are described from subalpine habitats in the subarctic of the Soviet Far East.

Feeding activities of freshly hatched larvae of Urophora cardui (L.) cause the formation of callus-filled channels which later serve as the routes by which adults exit their galls. Callus cells of the channels deteriorate the following spring when the gall is wetted by melting snow and rainfall. Establishment of U. cardui as an agent in the biological control of Canada thistle may be impaired in habitats with insufficient moisture to degrade the callus plug.

On 20 September 1980 a single male gypsy moth, Lymantria (= Porthetria) dispar (L.), was found in a pheromone trap near the Arts and Culture Centre, Corner Brook, Newfoundland. Identification was confirmed by Dr. J. D. Lafontaine, Biosystematics Research Institute, Ottawa. This was the first record of the gypsy moth in Newfoundland, which is separated in the south 144 km from Nova Scotia and in the north 14 km from Labrador.