Ceutorhynchus litura (F.) laid an average of 123 eggs per female. Development from egg to adult took about 6 weeks at room temperature, followed by an obligatory diapause of 3–4 months. In laboratory rearings a maximum of only an 8-fold increase over the original breeding stock was achieved in one generation. The weevil was released against the weed Canada thistle (Cirsium arvense (L.) Scop.) near Belleville, Ont., in 1967. Near the centre of the release site on about 400 m2, thistle shoots have decreased to 4% of their former density of about 3–7 shoots per 0.25 m2. Circumstantial evidence indicates that the weevil aided in the spread of thistle rust Puccinia punctiformis (Str.) Rohl.

Little attention has been given to the selection of the most effective agents for the biological control of weeds. The consequence has been a needlessly high failure rate and cost. Seven methods for their selection are discussed and a scoring system proposed as a means of incorporating their best features.

In Holomelina immaculata (Reakirt) periodicity of male attraction to synthetic 2-methylheptadecane, the female-produced sex pheromone, is modified by temperature cues. In the field this response interval occurs from approximately sunset to about 4 h after sunset on a warm day and night (30° to 17 °C) and for the 2 h prior to sunset on a cool day and night (23° to 16 °C).

In laboratory studies at 24 °C female H. immaculata placed in continual scotophase have an endogenous calling rhythm, but they are apparently inhibited from calling by constant photophase. In 16:8 or 12:12 light–dark cycles at 24 °C calling occurs from the 2nd to the 6th hour of scotophase, whereas at 15 °C calling takes place from the initiation to the 5th hour of scotophase. The critical cues governing initiation of calling behaviour are lights-off or a temperature decrease cue, and a temperature decrease signal overrides the apparent inhibitory effect of continual photophase.

Immature stages of the pea aphid, Acyrthosiphon pisum (Harris), from viviparous, parthenogenetic populations, were exposed to hot and cold temperatures outside the favorable zone. Between 34.5 °C and 41.0 °C, time to 50% mortality (LT50) decreased approximately according to the relation log Y = 10.30−0.22X. From −9 °C to −12 °C, LT50 decreased rapidly and changed little with further temperature decrease to −16 °C.

Survival was affected by acclimation which was complete after 1 to 2 days. Acclimation to temperatures between 10 °C and 25 °C changed LT50 by as much as 1.3 times at 39 °C and 2 times at −12 °C.

Temperature tolerance increased with age.

A study was conducted in a mature apple orchard in Nova Scotia to compare the density of eggs of the European red mite, Panonychus ulmi (Koch), over the whole tree to their density on a selected area using a random selection and standard selection technique. Both methods provided nearly equivalent estimates of population densities for generations 2 and 4 but not for generation 3. The population estimates based on sampling from the selected area overestimated the whole tree population.

Optimum allocation of sampling resources may be obtained by sampling a small number of clusters from each of a large number of trees.

Interference between Formica obscuripes Forel and Dolichoderus taschenbergi (Mayr) colonies was observed in the laboratory and in the field. D. taschenbergi was by far the stronger competitor in the laboratory test, but only slightly superior to F. obscuripes in the field. It was concluded that colonies of F. obscuripes and D. taschenbergi transplanted to areas requiring ant protection would not be rendered ineffective by the presence of previously established colonies of either species.

A new species, Ctenicera sleeperi, from the desert areas of southern California is described and illustrated. It is closely allied to C. pilatei (Champion), new combination, from Yucatan, Mexico; both species differ from all other nearctic species by the presence of setae on the tarsal claws and by the absence of the cubital crossvein. The differences between the nearctic species of Esthesopus and Horistonotus are discussed and illustrated. H. mitis Horn is transferred to Esthesopus, with H. pallidus Fall as a synonym.

A 10,000 acre stand of mature balsam fir, in Temiscouata County, Quebec, which had a spruce budworm population of about 21 larvae/18 in. branch-tip was sprayed with a Bacillus thuringiensis + chitinase formulation. Aerial spraying was carried out by three TBM aircraft between 4 and 7 June 1972, when insect development was at the peak of the third instar. Where the quantity of B. thuringiensis colonies per square centimeter was higher than 77 and spray deposit higher than 0.4 gal/acre (U.S.), larval mortality was between 84% and 93% compared with between 39% and 53% in the check plot. Foliage protection was 47%. The results indicate the possibilities of using B. thuringiensis + chitinase to control spruce budworm infestations.

Two new species of the genus Lygus Hahn are described: potentillae from Canada, Alaska, and Colorado; and mexicanus from Mexico and Texas. Lygus abroniae Van Duzee is considered to be a typical member of the genus Lygus. The seasonal colour variations of the three species are noted, their relationships to other species in the genus are discussed, and their host plants are given.

A method for preparation, dispensing, and handling of large volumes of a synthetic diet for rearing a variety of insect species is described. A 16.5 imp. gal electrically-heated steam-jacketed kettle fitted with a bridge-mounted mixer is used to liquefy the agar and to mix the ingredients. An automatic filler is used to dispense measured amounts of diet directly from the kettle into plastic creamer cups set up on disposable pressed-board cafeteria trays. The trays facilitate easy handling and storage of diet and also serve as rearing units. The composition of the diet, the amount of ingredients to prepare 15 imp. gal, and some of the insect species successfully reared on the diet, are also noted.

Injury to sugar maple buds, shoots, twigs, and stems resulted in forked trees in Upper Michigan. Six species of insects were observed to feed on buds: The lepidopterans Proteoteras moffatiana Fernald (Olethreutidae), Obrussa ochrefasciella (Chambers) (Nepticulidae), Choristoneura rosaceana (Harris) and Cenopis pettitana (Robinson) (Tortricidae), and the coleopterans Phyllobius oblongus (L.) (Curculionidae) and Platycerus virescens (F.) (Lucanidae). Twig and shoot damage resulted from severed shoots, twig cankers, and scarring resembling weevil feeding injury. Stem damage was caused by breakage and browsing animals. Bud injury averaged 5.80% per year, twig damage 3.18% per year, and stem breakage 0.36% per year. Injuries to terminals resulted in 85% forked stems, 8% single stems, 3% stunting, and 4% unaffected.

A new monotypic genus, Bolbothyreus, is proposed for the South American species Stenaspidius ruficollis (Bruch). The new genus seems most closely related to Bolbapium Boucomont from South America and less so to Stenaspidius Westwood from Australia.

A new beech-inhabiting aphid, Phyllaphis grandifoliae, is described from Ontario. Its relationships to other species are noted. A key to species of Phyllaphis is given.

Semium villosum n. sp. is described from Mexico. S. hirtum Reuter is known to occur in Canada and Mexico. The 4 known species are keyed and illustrated.

The mosquitoes Anopheles barberi, Orthopodomyia signifera, and Orthopodomyia alba are recorded for the first time in Canada. All three species were found breeding in the water-filled rot cavities of trees in the deciduous forest of Point Pelee National Park, Ontario. Attention is drawn to the probable rarity of these mosquitoes in Canada and their conservation is recommended.