Rates of development of selected stages and complete development of the carrot weevil, Listronotus oregonensis (LeConte), were determined in the laboratory at controlled temperatures ranging from 17.5 to 30°C. Within that range of temperature, rates of development increased with temperature. Fitting the data to a cubic polynomial function provided an excellent description of the relationship between temperature and rate of development for all stages as shown by R2 values of at least 0.98.

An investigation of the insects that damage cones (megasporangiate strobili) and seeds of tamarack [Larix laricina (Du Roi) K. Koch] in New Brunswick was undertaken. During two growing seasons (1982 and 1983) cones were removed from natural and planted stands of tamarack on a weekly basis. These cones were dissected, the nature and amount of insect damage recorded, and insect habits documented. Efforts were made to rear to adults any destructive insects encountered in order to identify them and to isolate parasites. Insects destroyed from 24.6 to 88.0% of the seed produced in the stands under study. Larvae of the spruce budworm [Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae)] and the cone maggot [Lasiomma viarium (Huckett) (Diptera: Anthomyiidae)] were responsible for most of the damage. Among insects that caused lesser amounts of damage were a cone midge [Resseliella sp. (Diptera: Cecidomyiidae)], a seed chalcid [Megastigmus sp. (Hymenoptera: Torymidae)], and various lepidopterous larvae. Applications of the insecticides carbofuran and dimethoate reduced the amount of insect damage. Carbofuran applied at the rate of 13.5 g active ingredient per centimetre of diameter at breast height provided the best protection. Trees treated in this manner had 37.0% of their seeds destroyed by insects as opposed to 74.2% on control trees.

Factors influencing spruce budworm (Choristoneura fumiferana) mating and mating suppression in an enclosed environment in the laboratory were investigated to develop a quantitative assay suited to statistical analysis. Mating in the absence of the two major components of spruce budworm sex pheromone (control) was not affected by changes in moth population density nor by increasing the experimental duration from 20 to 44 h. The proportions mated increased with an increase in the male:female ratio to 1.5:1 and when the experimental duration was prolonged to 68 h. Using a population density, sex ratio combination of 15:10 (male:female) the proportions of mated females decreased with increasing source concentrations of the two major spruce budworm sex pheromone components (95:5 E/Z-11–14-tetradecenal). This effect was diminished with increases in the population density and with extended test duration. Mating in the presence of pheromone remained lower than controls over all durations tested.

In 1982, the synthetic pyrethroid, cypermethrin, was among the insecticides recommended as a spray for control of adult flea beetles attacking canola crops in Saskatchewan (Saskatchewan Agriculture 1982). Growers reported some problems with its effectiveness at the recommended rates of 14–20 g AI/ha, however, and the recommendation for its use against flea beetles was subsequently discontinued. Laboratory spray trials were begun in 1982 to determine if post-treatment temperature affected the contact toxicity of cypermethrin to adults of the major pest species, Phyllotreta cruciferae (Goeze), and if the dosage that had been recommended was adequate as a contact spray.

Oxydemeton-methyl, azinphosmethyl, dimethoate, and acephate were evaluated in Douglas-fir seed orchards for control of Douglas-fir cone gall midge, Contarinia oregonensis Foote, and Douglas-fir seed chalcid, Megastigmus spermotrophus Wachtl. Results varied with infestation levels and specific chemicals. There was no significant reduction of infestation levels of either insect with the application of acephate. Oxydemeton-methyl injections, oxydemeton-methyl spray, and dimethoate significantly reduced cone gall midge damage. All four chemicals were ineffective against the seed chalcid for infestations of less than 10% of extractable seed. Oxydemeton-methyl injections, azinphosmethyl, and dimethoate significantly reduced the incidence of seed chalcid when the infestation was high (61%). There was no statistically significant difference (α = 0.05) for pairwise comparisons between chemicals which significantly reduced the infestation levels of either insect.

Efficient sampling procedures for estimating densities of eggs of Douglas-fir cone gall midge (DFCGM), Contarinia oregonensis Foote, on individual trees as well as for orchards were developed from data collected in Douglas-fir seed orchards in 1978–1981. Egg distribution was contagious and generally fitted the negative binomial distribution on individual trees, but a common k could not be estimated. Tree and crown level affected density of midge eggs within orchards. Average density at the midpoint of the cone-bearing portion of the crown was not significantly different from the tree average. The optimum sampling pattern in an orchard, i.e. one conelet from the midpoint of the cone-bearing portion of each of 120 trees, would require 120 person-hours to process the samples when DFCGM egg densities are high (worst-case situation).

The 1st-instar larva of Metrius contractus Eschscholtz is described and illustrated. The larva differs from those of other Carabidae (except some species of ozaenines) by having the epipleurites of the 9th segment and the tergum of the 8th segment transformed into a plate and by having the urogomphi antler-like and located in a vertical plane. These character states support the hypothesis, based on published analysis of the adult structures, that the monogeneric tribe Metriini is closely related to the tribes Ozaenini and Paussini. The ranking of Metrius, Ozaenini, and Paussini is re-evaluated and it is proposed that these three groups be combined in one tribe, the Paussini (sensu novo). The tribe Paussini, thus constituted, is placed with the tribes Brachinini and Crepidogastrini in the subfamily Paussinae. The relationships of the subfamily are unclear, but it probably represents a primitive element of the Carabidae. Based on the available data on bionomics and larval morphology of paussines, it is suggested that larvae of Metrius live in rotten logs and depend for their survival on some kind of animal which they attract through a secretion released at the extremity of the abdomen. The kind of animal and the type of interaction between the animal and the Metrius larvae remain unknown.

A series of samples of the twospotted spider mite, Tetranychus urticae Koch, from 16 experimental populations on “Totem” strawberry, Fragaria × ananassa Duch., were examined to determine the index of dispersion, the variance–mean relationship, the distribution, and the relationship between the mean number of T. urticae/leaflet and the proportion of leaflets without T. urticae. The slope of the variance–mean relationship, 1.64 ± 0.0355(SE), did not differ between sample dates but the intercept decreased significantly (p < 0.01) from 2.56 ± 0.0969 before harvest to 1.76 ± 0.140 during harvest. At 0.0136 T. urticae/leaflet before harvest and 0.0644 T. urticae/leaflet during harvest, the variance equaled the mean, implying that at these densities the data followed the Poisson distribution. Above these densities the data were overdispersed, most samples conforming with the negative binomial distribution but some tending towards greater dispersion than the negative binomial. There was no common k for the negative binomial nor did the data fit the expectation for 1/k that was consistent with the variance–mean relationship. A distribution-free sampling scheme based on the sample mean and the proportion of leaflets without T. urticae () was developed. Tetranychus urticae density can be quickly determined in the field using the naked eye, by iteratively observing leaflets for the presence or absence of T. urticae and referring to a small table that gives both the mean density for a given and the number of leaflets required to obtain a specified standard error.

Various temperatures were tested for maintaining Pteromalus puparum (L.) adult parasites in the laboratory. Survival of adults caged in groups and supplied with a 10% sugar solution exceeded 80% after 30 days at 15 and 23°C. When kept individually in small gelatin capsules at 3°C, survival was good only up to 15 days. The gelatin capsules, however, allowed easier handling of individual parasites without disturbing the entire group.

Larvae of Coquillettidia pertubans (Walker) are found in some marshes of permanent water with stands of aquatic vegetation. Eighty-six marshes, located within a 400-km2 area of Hennepin County, Minnesota, were examined in the fall of 1984 to determine factors that characterize C. perturbans breeding sites. We found that C. perturbans larvae attached to the roots of primarily Typha species although other plant species were also used. The water in sites with larvae was significantly deeper, lower in dissolved oxygen, and contained a significantly thicker layer of organic debris than sites without larvae. Larvae were associated with sites where Typha had specialized structures called water roots, which grow in the water column. Larvae inhabiting floating mats of vegetation were associated with interior openings within the mats.

Damage at cone harvest by the Douglas-fir cone gall midge, Contarinia oregonensis Foote, was positively correlated with the number of egg-infested scales per conelet in the spring. Reducing the average number of galled seeds per cone by 1.5 increased the average number of filled seeds per cone by 1.0 in insecticide trials. Optimum sample sizes for estimating average densities of egg-infested scales were calculated to be one conelet per tree and 150 trees per orchard. The mean crowding variable was linearly related to average density so a sequential sampling technique relative to a critical density, using Iwao’s procedure, was developed for determining the need of control actions.

Pea aphids, Acyrthosiphon pisum (Harris), were sampled from 1980 to 1983 in field peas, Pisum sativum (L.), in Manitoba. Sweep and foliage samples were taken in commercial fields and plots. Aphids were found in late May or early June soon after the crop emerged, but populations were low throughout June. Populations increased in July, when the crop was flowering and producing pods, and peaked in the latter half of July or early August in 3 of the 4 years, when pods were maturing. Populations decreased rapidly after the peak, as the plants senesced. In 1980, a drought year, aphid densities were low and the populations peaked in the middle of August. From 1981 to 1983, densities exceeded the economic threshold in all commercial fields and all but one of the plots that were sampled.

This paper treats taxonomically 10 North American species of the genus Pardosa. The coloradensis group contains only the three species Pardosa metlakatla Emerton, 1917, Pardosa coloradensis Banks, 1894, and Pardosa ontariensis Gertsch, 1933 (= Pardosa pristina Fox, 1937, new synonym). The xerampelina group contains three Nearctic species, namely, Pardosa diuturna Fox, 1937, Pardosa xerampelina (Keyserling, 1877) (= Pardosops impavidula Roewer, 1954, new synonym), and Pardosa nordicolens Chamberlin and Ivie, 1947. The lapponica group comprises the Holarctic species Pardosa lapponica (Thorell, 1872) (= Pardosa harperi Bishop, 1949, new synonym) and the Nearctic Pardosa concinna (Thorell, 1877). The tesquorum group is composed of the Holarctic species Pardosa tesquorum (Odenwall, 1901) and the Nearctic Pardosa mulaiki Gertsch, 1934.

Several insect growth regulators (IGRs) were tested against citrus thrips, Scirtothrips citri (Moulton), in Munger cells. In all larval tests, the IGRs worked by preventing the thrips from developing to the pupal or adult stages. After exposing adult females to IGR residues, numbers of emerging progeny were reduced, although these results did not always rank the IGRs in the same order as the larval tests. The most effective IGR tested was UC84572, followed by cyromazine. Avermectin B1, a streptomycete-derived lactone, did not show IGR activity but acted as an insecticide and controlled the thrips at a much lower percentage active ingredient.

Normally, Urophora cardui (L.) induces galls on the stems of Cirsium arvense (L.) Scop. (Canada thistle). However, six galls were found in flowerheads when flies were cultured in growth chambers. All flowerhead galls developed from receptacle tissues of male thistle capitula and were structurally similar to those induced from stem tissues. The appearance of these atypical galls contributes to our understanding of organ specificity of gall-inducing insects.

Sarcophagid larvae were occasionally found in pitcher-plant (Sarracenia purpurea L.) leaves from mid-June until early September during 1982–1984, in bogs located at The Pas (53°50′N, 101°15′W) and Patricia Beach (50°25′N, 96°36′W), Manitoba, and Kenora, Ontario (49°47′N, 94°29′W). Larvae were collected primarily from “new” leaves (current year's growth), but also from “old” leaves (leaves from the previous summer which retain water throughout the current season). Only one sarcophagid larva was found per leaf.

La poursuite de l'échantillonnage de Culicides larvaires afin de déterminer la colonisation par les populations de moustiques d'un gîte nouvellement aménagé, nous a permis de capturer deux larves de Culex tarsalis Coquillett le 28 août 1984. Il s'agit de la première mention de cette espèce au Québec.

Ether extracts from Eurygaster integriceps (Evlakhova and Chekhourina 1962) and Bombyx mori (Koidsumi 1957) have been found to inhibit germination of conidia of the white muscardine fungus, Beauveria bassiana, and of Aspergillus flavus, respectively. Free fatty acids, such as caprylic acid, which inhibit the germination of B. bassiana conidia (Smith and Grula 1981), have been found on the cuticle of several insects (Smith and Grula 1982; Saito and Aoki 1983). However, Smith and Grula (1982) found that the toxicity of free fatty acids to B. bassiana conidia in vitro is dependent on the nutritional conditions present. The germination of B. bassiana conidia onthe integument of the mountain pine beetle, Dendroctonus ponderosae, is seldom observed without nutrient enhancement (Hunt et al. 1984). My objective was to determine whether the relative absence of conidial germination on D. ponderosae cuticle is due in part to the action of toxic free fatty acids.

The carrot weevil, Listronotus oregonensis (Le Conte), is an important pest of carrot and celery in eastern Canada (Stevenson 1985). In Quebec, it is univoltine and overwinters as adults (Boivin 1985). At present, the only way to control this pest is with chemical insecticides applied either as granules at seeding time to control the larvae or as foliar sprays to control the adults before they start to oviposit. If integrated pest management (IPM) programs are to be applied to crops attacked by the carrot weevil, additional control methods are needed.