At constant temperatures between 10.0° and 32.2°C with 16 h photoperiod development of eggs and nymphs was slowest at 10.0° (61.8 days av.) and most rapid at 26.7°C (27.0 days av.). Mortality of eggs and nymphs was moderate (43.7%) at 10.0°, least (24.2%) at 21.1°, and 100% at 32.2°C. Between 15.6° and 35.0°C, 16 h photoperiod, fecundity of winter form adults was greatest (486.3 eggs av) at 15.6° and lowest (0.0 eggs) at 35.0°C. For summer form adults fecundity was moderate (212.4 eggs av.) at 15.6°, maximum (444.9 and 447.3 eggs av., respectively) at 21.1° and 26.7°C, and least (2.8 eggs av.) at 35.0°C. Longevity of male and female winter and summer forms was greatest at the low temperature and least at the high temperature. These data are discussed with relation to field observations of natural pear psylla populations and control programs.

The predaceous mite Balaustium putmani Smiley was studied in the laboratory and in apple orchards in southern Ontario. A rearing technique was devised which facilitated the study of the life history and behaviour of individual mites.

Temperature and moisture influenced the development and hatching of eggs. In the presence of water, development proceeded more rapidly at the higher temperature of the 10°–25°C range tested. In the absence of water no development occurred. Larval B. putmani are free-living predators and although some were observed feeding periodically on pollen grains, they could not survive solely on this diet. All three motile stages are predators of a wide range of small, soft-bodied arthropods, but feed mainly on eriophyids and phytophagous tetranychid mites. The rate of consumption of the eggs and motile stages of the European red mite was determined for each motile stage at 20° and 25°C. Insemination is by externally deposited spermatophores and in the adult females, no facultative parthenogenesis was evident.

An equation developed in 1972 and 1973 for predicting the number of adult pecan weevils, Curculio caryae (Horn), in pecan trees was modified to include natural survival and evaluated for estimating weevil population and for determining the initiation of control measures. This method of scheduling insecticide applications resulted in a lower infestation of pecan weevil than jarring, the most commonly used sampling method, with the same number of insecticide applications. The use of a prediction equation for estimating C. caryae populations to determine economic thresholds looks promising for the researcher, grower, or pest management specialist.

Regression equations of per cent defoliation of white birch stands, Betula papyrifera Marsh., to birch casebearer, Coleophora fuscedinella Zeller, eggs or larvae had precisions (standard error of the estimate, b) of about 20% of the estimate. Although log-transformation of counts stabilized the variance, it did not increase the precision of the equations. Precision of regression estimates based on data from whole-stratum sample units differed little from that from only four mid-crown branches. The latter sample universe is smaller and more rapidly examined.

Adult and puparial keys are presented for five Microdon species occurring in eastern Washington and northern Idaho. The original description of Microdon cockerelli Jones is revised, and a new species of Microdon is described.

Laboratory and field studies indicate that differences in gypsy moth egg mass characteristics can be related to larval density and natural diet. Egg mass characteristics are valuable indices of population quality as well as future population levels. Laboratory crowding reduced number of eggs/mass but did not affect egg size. Field collected egg masses from various population levels in Massachusetts also varied in egg number/mass, but egg size could not be directly correlated to density. Laboratory rearing of larvae on several natural diets produced differences in both egg number and size. Maple diets produced egg masses with fewer, smaller eggs, as compared with oak diets. Field collected egg masses also varied in mean egg size, according to host tree species. Thus, forest composition may directly affect the quality of gypsy moth populations, as well as numerical levels. Increasing density could affect egg size indirectly, by forcing gypsy moth larvae to feed on unfavorable host foliage.

Nearly 1300 Lathrolestes nigricollis (Thompson) and 900 Grypocentrus albipes Ruthe (Hymenoptera: Ichneumonidae), were released in Quebec, in 1974 and 1975, in an effort to control the birch leaf-miner, Fenusa pusilla (Lep.). The two species of European parasites were liberated in stands of gray birch (Betula populifolia Marsh.) in four localities of the St. Lawrence River Valley. Mating was well observed for L. nigricollis but not for G. albipes, and both male and female progenies were later recovered for the two species. Three generations of parasitoïds, the first of which overwintered, were recorded at the end of the summer in 1975. Establishment of these parasites of F. pusilla is very likely to occur in the near future.

The population densities of several major apple pests and their natural enemies were studied in an insecticide-free young bearing orchard and in an older orchard of semidwarf trees on an integrated control program. In mature orchards of standard size trees, greater natural mortality occurs than that reported in this study. Over a 5-year period most pests, with notable exceptions, increased rapidly under insecticide-free conditions whereas occasional numerical surges of certain pest species occurred under the mild insecticide program. Insect damage on fruit at harvest averaged 24% in the insecticide-free orchard and 8% in the integrated control orchard which had 2.4 times more harvested fruit.

The effect of density on host–parasite interactions between Hypera postica (Gyllenhal) and Bathyplectes anurus (Thomson) was studied in a caged system in the laboratory. There was no significant relationship between proportion of hosts parasitized and host density. The frequency distribution of the parasite’s eggs approximated the Poisson distribution in 83% of the cases. There was a quadratic relationship between number of superparasitized hosts and parasite density. However, no significant correlation between proportion superparasitized and host density was detected. The Nicholsonian area of discovery was inversely related to parasite density with a strong mutual interference constant of −.467.

The absence of males in 1000 adults examined over a 2 year period, the facility with which unmated females deposited eggs, and the high percentage (86%) of these eggs which hatched are presented as evidence for obligatory parthenogenesis in Cloeon triangulifer McDunnough. It is suggested that the unusually long (June to November) emergence period of the species is a result of parthenogenesis.

This paper presents a sampling plan for estimating numbers of H. postica adults in alfalfa. The plan is based on vacuum samples of foliage and ground litter and uses a half ft2 (465 cm2) as the sample unit. For typical levels of infestation during the oviposition period in early spring, estimates with reasonable precision may be obtained by taking 60 randomly selected units from a field, at a total cost of 6 man-hours. For those in early summer, not more than 20 units are required.

For all population densities, the pattern of counts was well described by the negative binomial distribution. However, at densities below unity, the Poisson function described the data equally well.

An apparatus is described which permits either continuous or interrupted flow of diet under a membrane through which piercing and sucking insects can feed. The flow does not affect feeding behaviour while allowing a replacement of one diet by another which is 99% effective in less than 2 sec, using approximately 2 ml of diet. Monitoring electrical conductivity of a diet at the feeding membrane permits quantitative evaluation of exchange efficiency. Use of this apparatus in experiments on dietary requirements and mass-rearing are discussed.

A temporary pond close to Calgary, Alberta, was studied for 2 years. In the spring of the first year (1974) the pond filled with water to a much higher level than normal and it did not dry and reflood until August. The first flooding hatched eggs of Aedes euedes, A. cataphylla, A. excrucians, A. fitchii, A. flavescens, and A. mercurator; the second flooding hatched eggs of A. vexans and A. cinereus. Estimates of larval population size were made for the latter two species and little larval mortality occurred until the pond was reduced to a few small puddles, when larvae became stranded. The pond dried completely before the pupal stage was attained. Fifty per cent of surviving A. vexans larvae attained instar II in 3.7 days, instar III in 6.6 days, and instar IV in 10.3 days. A. cinereus developed more slowly.

In the second year (1975) the pond contained water from the middle of April to the beginning of June, and did not refill in the summer. Estimates of larval population sizes were made for A. euedes and A. mercurator. These larvae shared a preference for the deeper water in the centre of the pond. Their numbers declined at rates of 9% per day for A. euedes and 7% per day for A. mercurator. Larvae in the second instar survived a period of 3 days when the water surface was covered with ice and snow, but A. euedes experienced a sharp drop in numbers at this time.

Fifty-three per cent of the eggs of A. vexans survived a period of 1 year in areas not flooded with water at appropriate temperatures for hatching.

Forty exotic maize inbred lines from 10 countries with known resistance or susceptibility to the European corn borer, Ostrinia nubilalis (Hübner), were used to study the effect of plant resistance on borer survival from natural overwintering conditions and particularly the fecundity of the female moth during the following summer. Also, additional information was obtained on different biological characters of the insect. Resistant and susceptible lines were grouped according to their leaf feeding ratings (antibiosis), per cent borer survival at pollination time or at harvest (tolerance). Each specimen observed was kept on the same plant tissue until pupation. The number of eggs and egg masses/female was significantly higher only when lines are grouped according to their leaf feeding ratings. No significant differences were obtained in most biological characters of borers fed on resistant or susceptible maize lines: spring pupation, pupal parasitism, mortality and weight, moth emergence and sex ratio.

In this paper, a stochastic analysis approach for predator–prey systems modeling is developed. The states of the system are assumed to have a natural probabilistic variation. Elements of queueing theory are used to describe these variations and to obtain both the transient and steady-state results for the system. The predator is considered analogous to a service facility and the prey as customers to be served. The Holling disk equation and mantid–fly experiments are analyzed by this approach. The method provides a framework for a straightforward synthesis of the system components and is readily generalized for multiple predator systems. Furthermore, hunger and other behavioral aspects can be easily incorporated into the mathematical analysis.

Two leafroller spades are major pests of apple in British Columbia, Archips argyrospilus (Walker) and Archips rosanus (Linnaeus). Field observations showed that both species overwinter in the egg stage and that larval emergence times are similar. Experiments demonstrated that both species are susceptible to sprays of azinphos-methyl, diazinon, or trichlorfon applied at either the pink bud or petal fall stages. Dipel (Bacillus thuringiensis) failed to control larvae of either species.

The type material added to the Coleoptera Section of the Canadian National Collection of Insects from 1 January 1969 to 31 December 1973 is catalogued. This new material consists of 258 holotypes and 129 allotypes; 42 species are represented by syntypes and 499 by paratypes or paralectotypes. The reference to the original description for each species is cited. All data associated with the specimens are quoted except in the case of paratypes, paralectotypes, and syntypes. An index to all species is included.

The efficiency of Berlese-Tullgren funnels in removing the rusty grain beetle, Cryptolestes ferrugineus (Stephens), from wheat samples was tested by adding adults and larvae to wheat samples. The recovery of adults from 300 g samples was 79% at 12.3% moisture content (m.c.) and 49% at 16% m.c.; from 150 g samples the recovery was 84% at 16% m.c. The number of adults recovered represented at least 98% of those that did not escape from the top of the samples. The number that escaped varied with sample size and moisture content. The recovery of fourth instar larvae was 78% from samples of 300 g at 16% m.c. The percentage of first and second instar larvae recovered was 5.8 when larvae alone were mixed with the wheat sample and left for 65 h, 10.6 when larvae in flour were added to the surface of the wheat sample, and 27.9 when larvae in flour were added to the centre of the wheat sample.

Adults of five species of flea beetles were found attacking rape crops (Brassica napus L. and Brassica campestris L.) in the Canadian prairie provinces from 1971 to 1974. Phyllotreta cruciferae (Goeze) was the most abundant and serious pest, followed in order by Psylliodes punctulata Melsh. and Phyllotreta striolata (F.) (= vittata (F.)), while Phyllotreta albionica (Lec.) and Phyllotreta robusta Lec. were present only occasionally. The four Phyllotreta species confined their feeding largely to cruciferous plants, but Psyl. punctulata had a broader host range. All of the five species overwintered as adults, usually in leaf litter or turf beneath hedges, poplar groves, or fencerows, or sometimes in the soil in fields, and all became active with the arrival of warm sunny weather in the spring, with Psyl. punctulata usually being the first to appear. All appeared to have but one generation per year, with mating and egg laying occurring in the spring, the larvae inhabiting the soil and feeding on host-plant roots, and the new generation of adults emerging from pupae in the soil in late July and in August. The overwintered adults usually died in late June or early July, so there was a period in July when adult flea beetles were scarce. The most serious damage to rape crops by flea beetles was caused by overwintered adults attacking seedling crops in the spring; movement of these beetles into crops took the form of a creeping infestation moving from plant to plant into the field from nearby volunteer rape of cruciferous weed feeding grounds, or a more rapid and even infestation of a whole field with flight probably being the major method of movement. Flea beetles fed most actively when the weather was sunny, warm, and dry; cool damp weather reduced the intensity of attack and aided plant growth. Shade, such as exists in a healthy stand of rape beyond the pre-bloom stage, also inhibited attack. Occasionally, late-maturing rape crops were damaged in late summer by new generation adult flea beetles, particularly P. cruciferae, feeding on the green epidermis of the stems, leaves, and pods.

A field key for separating the five flea beetle species attacking rape crops in the Canadian prairie provinces is given.

The only confirmed host plant of Tingis ampliata H.-S. (Tingidae: Heteroptera) is Canada thistle (Cirsium arvense (L.) Scop.). For this and other reasons, T. ampliata appeared to be a promising biocontrol agent for use in Canada. However, in the laboratory, T. ampliata developed fertile eggs while feeding on the two economic plants globe artichoke (Cynara scolymus L.) and safflower (Carthamus tinctorius L.), and nymphs developed to adults on globe artichoke. Therefore, T. ampliata should not be released in Canada.