Growth rate, diapause incidence, and diapause intensity were different in two strains of corn borers found in southwestern Ontario. Crosses between these two strains demonstrated that growth rate was female sex linked while diapause incidence was male sex linked. The effect of these two characteristics on hybridization is discussed.

During the past decade, larvae of the housefly, Musca domestica L., have been reared routinely in a medium containing two parts of wheat bran and one part of alfalfa meal, moistened with a yeast suspension and a solution of malt euuact. The recent appearance of a standard mixture of wheat bran (33.3 per cent), alfaIfa meal (26.7 per cent), and brewers grain (40.0 per cent), called CSMA (formerly NAIDM), has further simplified the rearing of this species of fly. This note reports a modification of the CSMA medium and its use in the sterile culture of housefly larvae.

The relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.

Adult carabid beetles of the species Harpalus pensylvanicus (DeGeer) and Pterostichus melanarius (Illiger) were collected from a cultivated field near London, Ont., and brought into the laboratory for observation and mass culture in terraria; the culture method is described. Both species oviposited successfully in the laboratory; P. melanarius produced as many as 134 eggs/female over a 6-month period, whereas H. pensylvanicus deposited only about 10 eggs/female under similar conditions. However, percentage emergence in Harpalus was substantially higher (62.6) than with Pterostichus (36.8 and 45.7). Large numbers of first- and second-instar P. melanarius larvae may be obtained by using the rearing method described. The low oviposition rate of H. pensylvanicus made large-scale rearing of this species difficult.

Observations are made on the mating behaviour and adult parasitization by horsehair worms (Nematomorpha) of Pterostichus.

Experiments were designed to determine the effects of low doses of some insecticides on the viability and physiological characteristics of commercial Bacillus thuringiensis (Berliner) as a prelude to studies on the susceptibility of lepidopterous forest defoliators to mixtures of bacteria and insecticides.

The results show that the insecticides tested had no effect on viability or physiological integrity of the bacteria.

Bacteria–insecticide combination effects varied from strongly antagonistic to strongly supplemental depending on insecticide or Thuricide® formulations and concentrations and on the relative susceptibility of the test species to either agent applied separately. Pyrethrum at 10−3 was highly potentiating to BT at 10−1 against third instar Halisidota argentata. Among Hyphantria cunea, a supplemental effect always resulted from combining Thuricide® at 10−2 with low concentrations of malathion, phosphamidon, or pyrethrum.

There was generally a drastic reduction in feeding activity among BT-treated insects and a further reduction among BT-chemical-insecticide-treated ones compared with controls.

During May, 1935, C. F. Doucette collected a few adult weevils on flower heads of mustard growing at the edge of a bulb field near Lynden. Wash. These weevils were recognized by the writer as apparently different from any of the species listed from North America, and a trip was made to Lynden on June 1, 1935, to obtain additional specimens. Specimens were also collected on mustard close to the northern limits of Bellingham, at two points between there and Lynden, north of Lynden, and in the vicinity of Nooksack, all in Watcom County. On the following day two specimens were collected on mustard at Big Lake, Skagit County. Big Lake is practically in the seed-growing section of the county, where a large portion of the cabbage seed used in the United States is produced. Weevils were determined by L. L. Buchanan as Ceutorhynchus assilmilis Paykull, and Mr. Buchanan stated that this species had not previously been reported from North America and that it appeared to be of considerable economic importance in Europe.

In the genus Ephoron of Japan three species are recognized: E. shigae (Takahashi), E. limnobium sp.nov., and E. eophilum sp.nov. This study includes a key to the species, a description of each species, and maps of species distributions.

Two localities in central Alberta yielding insects of Paleocene age are described. About half of the 176 specimens obtained are coleopteran larvae; many of the adults and larvae are members of aquatic groups.

Larvae of the larch sawfly, Pristiphora erichsonii (Htg.), feed on the foliage of conifers of the genus Larix. In Manitoba and Saskatchewan, where the studies described here were conducted, the native host is tamarack, L. laricina (Du Roi) K. Koch. At outbreak population levels larval feeding commonly causes complete defoliation. Trees show a marked reduction in foliage production after three or four successire vears af severe defoliation (6). As a consequence, larval starvation is commonly associated with declining host vigour. Starvation reduces the population size directly by causing larval mortality and indirectly by reducing the reproductive capacity of the partially starved survivors. This paper deals primarily with the measurement of the sub-lethal effects of starvation during the last larval stadium as studied in laboratory-reared and field-collected insects.

In 1910 in a paper on the parasites of the Gypsy and Brown-tail moths, W. F. Fiske calculated the mortality necessary to stabilize the gypsy moth population and stressed the importance of a sequence of parasites and predators attacking successive stages of the insect host, in the establishment and maintenance of satisfactory control. In 1912, in the bulletin entitled “The Importation into the United States of the Parasites of the Gypsy Moth and Brown-tail Moth”, L. O. Howard and W. F. Fiske studied the problem of a sequence of parasites much more fully. They then made the very important point that aggregate percentage of kill necessary for the control of an insect pest could not be secured by simply adding together the figures representing the kills resulting through attack by each of two or more species. It was going to be necessary, they said, to combine these several aggregates in a different manner. Thus a 50% parasitism of the eggs if it could possibly be secured, followed by another 50% parasitism of the caterpillars, could not by any possibility be considered as resulting in 100% parasitism or complete extinction but only in 50% parasitism added to 50% of what remained which amounted in effectto 25% of the whole. In this manner an aggregate of 75% only is secured. They said further that any specific amount of parasitism as 20% of the eggs, was neither more nor less, but exactly as effective as 20% parasitism of the caterpillars and pupae, in so far as its value in constructing the final aggregate was concerned. The principle they thus established, though it may seem obvious enough, had not apparently been previously recognized by workers on biological control and it is of the very greatest importance.

Data are presented which show that first brood codling moth larvae have a higher diapause rate (and are thus univoltine) if reared in apples crowded with other larvae than if they are reared in uncrowded apples. From this relationship, a theoretical mechanism is proposed to help explain the interaction of genetic and nutritional effects in determining the dominant voltinism strain in codling moth populations.

Pitfall traps provide an easy and inexpensive way to sample ground-dwelling arthropods (Spence and Niemela 1994; Spence et al. 1997; Abildsnes and Tommeras 2000) and have been used exclusively in many studies of the abundance and diversity of ground beetles (Coleoptera: Carabidae). Despite the popularity of this trapping technique, pitfall traps have many disadvantages. For example, they often fail to collect both small (Spence and Niemela 1994) and “trap-shy” species (Benest 1989), eventually deplete the local carabid population (Digweed et al. 1995), require a species to be ground-dwelling in order to be captured (Liebherr and Mahar 1979), and produce different results depending on trap diameter and material, type of preservative used, and trap placement (Greenslade 1964; Luff 1975; Work et al. 2002).

Laboratory studies show that diapause, or eonymphal development, has a temperature optimum approximating 8 °C, at which some 29 days are required for its completion. The optimum for morphogenesis is 22 °C. About 33 and 37 days for females and males, respectively, are required for its completion.

Field data for three sites with mean temperatures near 22, 19, and 16 °C. show that emergence took place earliest at the intermediate site and latest at the exposed site, which experienced the highest mean temperature. Emergence of males and females overlapped, but at the shaded site, having the lowest mean temperature, females emerged sooner than males, whereas the reverse was observed at the exposed site.

The length of the eonymphal stage in the field is dependent upon site temperature and can be predicted from laboratory data. The duration of the pronymphal stage is dependent not only upon site temperature, but also upon the length of time which has been required for eonymphal development. Thus the longer the eonymphal period. the shorter the pronymphal period. This compensatory mechanism is probably due to a temperature effect on any morphogenesis that takes place concurrently with diapause.

Among territorial syrphids, males of Eumerus tuberculatus (Rond.) are less aggressive than Merodon equestris (Fab.) and Eristalis tenax (L.) males. This difference in aggressiveness persists even when territorial pressures increase with increasing numbers of conspecifics.

Males of each species recognized conspecific females mainly by a combination of visual and behavioural cues. A territorial male might approach any intruder, but would only attempt to mate if, like the appropriate female, the intruder did not respond to the male's approach. Differences in behavioural patterns may be due to different mating strategies.

During an investigation into the importance of fungal disease as a factor in the control of orchard pests throughout the Annapolis Valley, Nova Scotia, the haemocoele of large numbers of Macrosiphum pisi (Kaltenbach) was found to be infected with a fungal growth that resulted in death. This fungus was identified from mounted specimens as Empusa (= Entomophthora) aphidis Hoffman.

Cumulative temperature requirements and development thresholds were determined for two populations of Dicyphus hesperus Knight, 1943 to compare their suitability for use in biological control in greenhouse vegetable crops. The populations were from near Summerland, British Columbia, Canada (49°36′N, 119°40′W, at 334 m elevation) and from near Woody, California, United States of America (35°42′N, 118°50′W, at 500 m elevation). Eggs of the California (CA) population had a higher cumulative temperature requirement for hatch than those of the British Columbia (BC) population. Males of the CA population had a slightly lower cumulative temperature requirement for development from hatch to adult than males of the BC population. The populations did not differ with respect to development thresholds. Males of the CA population experienced higher mortality during development at 35 °C than BC males or females of either population. Males and females of both populations developing at 35 °C were significantly smaller than those developing at more moderate temperatures. The differences between populations with respect to development were biologically trivial. With respect to the effects of temperature on development time under greenhouse conditions, the two populations appear to be equally suitable for use in greenhouses.

Eighteen piercing and sucking insects were identified as feeders on green pods of mustard crops, Brassica juncea (L.) Coss. in Saskatchewan. Of these, the false chinch bug, Nysius ericae (Shilling), Lygus spp., and the western damsel bug, Nabis alternatus Parshley, were found to carry the yeast Nematospora coryli Peglion internally. N. ericae was capable of transmitting this organism to seeds in healthy green mustard plants.

In the first paper of this series (3), the factors affecting flight, and the flight potential of egg-laden females of the European pine shoot moth, Rhyacionia buoliona (Schiff.), were discussed. It was shown that the adults are relatively strong fliers, with a potential flight range greater than indicated in much of the earlier literature. It was also pointed out that natural dispersal of this species is dependent upon flight and subsequent oviposition by gravid females because unmated females seldom fly, and little, if any, population dispersal occurs through the long range movements of early instars drifting on silk. This final paper of the series deals with field studies designed to obtain information concerning the dispersal tendencies of gravid females under natural field conditions.

An individual-based phenology model for western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), was developed using stage-specific rates of development, oviposition, and egg hatch observed under controlled conditions at several temperatures. Model output was compared with age distributions estimated by sampling field populations of budworm at several locations in British Columbia, Canada, over many years. The fit of the model was very good for the entire life cycle of the insect. We further validate the model by comparing output with independent observations of moth flight phenology of C. occidentalis and Choristoneura fumiferana (Clemens) in populations of Cypress Hills, Canada and illustrate spatial variation in the seasonal occurrence of early-stage feeding western spruce budworm over most of its range in western Canada. In addition to serving as the underlying structure for the modelling of population dynamics at the seasonal level, the model can be used to predict the time of occurrence of different life stages for precise timing of pest management operations.