The genus Trichosilia Hampson, until now monotypic, is revised to include 10 species, 4 of which are described as new: T. austrina Lafontaine, from Texas; T. woodiana Lafontaine, from northwestern Canada; T. boreana Lafontaine, from northern Canada and Alaska; and T. beringiana Lafontaine and Kononenko, from northwestern Canada, Alaska, and Chukotka, USSR. All species are illustrated and characters to distinguish the species are given. Distribution maps for the species and a phylogenetic analysis of the genus are also included.

The cold-hardiness of Pissodes strobi (Peck) and of its insect associates in leaders of Picea sitchensis (Bong.) Carr. was tested to determine whether the insect associates could be retrieved free of P. strobi for use in biological control attempts on P. strobi. Leaders were stored at −8, −16, or −26°C for periods from 1 to 14 days. All P. strobi were dead after 14 days at −16°C, whereas their dipteran predator, Lonchaea corticis Taylor, and hymenopteran parasites, Eurytoma pissodis Girault and Rhopalicus pulchripennis (Crawford), continued development after storage at −26°C. The scarcer Dolichomitus terebrans (Ratzeburg) (Ichneumonidae) survived similarly although we did not always find it in our samples; and the equally scarce Bracon pini (Muesebeck) (Braconidae) seemed susceptible to −26°C but continued development at −16°C. Of the few Allodorus crassigaster (Provancher) (Braconidae) obtained one adult emerged after 7 days at −16°C. These results show that in leader clipping operations now used for attempted control of P. strobi, most of the insect associates could be retrieved from the leaders after suitable cold treatment. Additional tests showed that cold-treated leaders could be stored outdoors in temperatures at least down to −20°C with little effect on adult emergence of insect associates. The field testing also showed that few P. strobi in leaders of P. sitchensis can survive overnight temperatures near −20°C.

Resistance to pyrethroid insecticides, identified previously in adults of Phyllonorycter blancardella (Fabr.), was shown to extend to both egg and larval stages. Eggs of both resistant and susceptible strains were more susceptible than larvae to various pyrethroid insecticides. Eggs treated 0–2 days post oviposition were more susceptible than 4- to 6-day-old eggs and/or larvae for both strains. Older larvae, especially from resistant strains, were less susceptible than early instars. For eggs and 1st-instar larvae, differences between resistant and susceptible strains were largely overcome by treatment with higher concentrations of permethrin. In the field, low levels of resistance were overcome by applications of permethrin at 212.5 g AI/ha diluted in 3370 L water/ha timed for first hatch of eggs.

An IPM program was developed to control Venturia inaequalis (Cke.) Wint., Lygus lineolaris (Palisot de Beaiivois), Conotrachelus nenuphar (Herbst), and Rhagoletis pomonella (Walsh), the annual key pests of apple orchards in southwestern Quebec. The program was found to control other pests, such as Orthosia hibisci (Guenée). Phytophagous tetranychids were controlled with the introduction of an organophosphate-resistant strain of Amblyseius fallacis Garman, Key pests were monitored carefully and pesticide applications were timed to correspond to their presence in the orchard. After an extremely severe winter and late spring frosts, the IPM program failed to provide commercially acceptable pest control. A measure to correct this problem is suggested in the text. This program reduced the cost of pesticide treatments by 34% when compared with pest control practices currently used by commercial growers in Quebec.

Two Sumithion® formulations were sprayed aerially to compare their effectiveness in controlling spruce budworm, Choristoneura fumiferana (Clemens), in balsam fir, Abies balsamea (L.) Mill. Sumithion 20% flowable, a new formulation, and Sumithion technical were applied twice at 210 g AI (in 1.5 L of spray mix)/ha using a Cessna 188 Agtruck equipped with four Micronair atomizers. More than 95% of the technical and <45% of the Sumithion flowable spray droplets were <50 μm in diameter. Larval reduction ranged from 67 to 84% in the Sumithion flowable plots, from 52 to 55% in the Sumithion technical plots, and from 28 to 38% in the untreated plots. Postspray residual populations averaged 4.1, 6.2, and 10.3 larvae per 46-cm branch in the flowable, technical, and untreated blocks, respectively. Defoliation in the Sumithion flowable block averaged 18.5% and was not significantly different from the technical block but both were significantly less (α = 0.05) than that in the untreated block, which averaged 46.2%. The results suggest that Sumithion 20% flowable was more efficacious in controlling spruce budworm than Sumithion technical insecticide.

Ce texte décrit deux nouvelles fourmis néarctiques appartenant au genre Leptothorax (stricto sensu). La première, L. retractus, occupe un territoire transcontinental, tandis que la deuxième, L. sphagnicolus, fut repérée jusqu’à présent uniquement dans les pessières tourbeuses de la région du Saguenay–Lac St Jean, au Québec. Leur nombre respectif de chromosomes se chiffre à n = 17–18 et n = 13. Toutes deux se distinguent par une production inusitée de formes femelles intermédiaires et une répartition géographique de nature boréo-tempérée. Leurs caractéristiques bio-écologiques connues et leurs relations taxonomiques dans le genre sont discutées.

Setodes furcatulus Martynov, S. amurensis Martynov, S. crossotus Martynov, and Leptocerus moselyi Martynov are redifined. Setodes obscurus n.sp. and Rhyacophila maritima n.sp. are described. Setodes argentatus Matsumura, Trichosetodes polonorum Botosaneanu, and Agapetus inaequispinosus Schmid are recorded for the first time from the Maritime Province.

Laboratory tests showed that a Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), strain collected from potatoes on a farm near Sherbrooke, Quebec, and known in 1979 to be resistant to most recommended organochlorine, organophosphorus, and carbamate insecticides, also had developed 23- to 38-fold levels of resistance to the pyrethroid insecticides permethrin, fenvalerate, and cypermethrin by 1982. Piperonyl butoxide (PB) had only a minor effect on fenvalerate and deltamethrin toxicity to insecticide-susceptible CPB and on deltamethrin toxicity to pyrethroid-resistant CPB. However, PB effectively synergized fenvalerate in pyrethroid-resistant CPB, e.g. a 1:8 fenvalerate:PB mixture was 12-fold more toxic than fenvalerate alone.

Experiments were done in fields of potato in Fredericton, New Brunswick, in 1981, 1982, and 1984 to determine the effect of native predators on the abundance of aphids. The populations of predators were altered by pitfall trapping within plots enclosed by polythene barriers and by applying a selective insecticide. The abundance of aphids was monitored in the enclosed plots and in unenclosed areas serving as control. The experimental design was successful at significantly reducing the numbers of Carabidae in the enclosures compared with the open plots. Aphid populations tended to be larger in the plots with depleted populations of Carabidae than in the control areas and were significantly larger in the plots where the insecticide depleted the populations of canopy level predators. These results suggest that the Carabidae play a relatively minor role in aphid control on the potato crop compared with specific predators.

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.

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.

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.

On 2 April 1986, while removing an accumulation of mosses from the roof of a covered picnic table near a home on Brookfield Road, St. John's (Fig. 1), several hundred larvae (leatherjackets) of the European crane fly, Tipula paludosa Meigen, were found overwintering in the moss between the slots of the asphalt shingles (Fig. 2). During the period 1971–1985 a heavy growth of mosses had become established in the slots between the shingles. Sufficient organic matter, together with particles of soil and sand, had accumulated in these slots to support the mosses, which gradually spread outward to the flat surfaces of the shingles (Fig. 1).