The twolined chestnut borer, Agrilus bilineatus (Weber) (Coleoptera: Buprestidae), is associated with mortality of stressed oaks in the eastern deciduous forests of North America. Beetles were attracted to stressed trees within hours of the onset of stress. We hypothesized that adult beetles rapidly locate suitable hosts by olfactory detection of tree-released volatiles. Trees with sticky-band traps and vane traps baited with crude steam distillates from inner bark of stressed white oaks, or with combinations of ethanol and oak volatiles, captured significantly more beetles than did water controls. Ethanol alone did not attract significant numbers of A. bilineatus. Eighty-two percent of beetles captured were females. Ethanol-baited traps captured large numbers of Cerambycidae, Scolytidae, and a few Cleridae, and these insects were not attracted to oak volatiles. Sticky-band traps were more effective than vane traps in capturing A. bilineatus and other Buprestidae, but Cerambycidae and Scolytidae were more effectively captured in vane traps. Our results show that A. bilineatus is attracted to oak volatiles but later successional beetles are attracted to ethanol.

Eight species of Chironomidae (Diptera), including Cricotopus sp. nr. tremulus, Tvetenia vitracies (Saether), Nanocladius (s.s.) cf. rectinervis (Kieffer), Nanocladius branchicolus Saether, Nanocladius (s.s.) cf. spiniplenus Saether, Paratanytarsus confusus Palmen, Polypedilum (s.s.) convictum (Walker), and Rheotanytarsus sp., are reported for the first time in phoretic association with nymphs of Pteronarcys dorsata (Say) (Plecoptera: Pteronarcyidae). The stoneflies and associated chironomids were found in rivers of central and northern Saskatchewan. Rheotanytarsus sp. and P. convictum were the most common ectosymbionts on P. dorsata. Phoretic larvae were found most frequently attached to the host’s metathorax. Pteronarcys dorsata nymphs may be ideal hosts for phoretic inhabitants because of their abundance, large size, and detrivorous habit.

The multivariate statistical techniques of canonical correlation and canonical redundancy analyses were used to assess the population structure of larvae of Sitona hispidulus (F.) in alfalfa field soil. A series of rhizosphere variables was correlated with a series of insect variables that represented the developmental stages of the insect to identify relationships between the insect and rhizosphere. Results indicated that 1st and 2nd-instar larvae were correlated with small root nodules and soil moisture, but not with taproot biomass. Third- and 4th-instar larvae and pupae were not correlated with any of the rhizosphere components measured. Fifth-instar larvae were associated with taproot biomass.

Seasonal and daily patterns of ballooning, and behavioral processes involved in aerial dispersal of the bagworm, Thyridopteryx ephemeraeformis (Haworth), were studied on Juniperus virginiana L. in Kentucky. The aerial dispersal period began in mid-May 1983 and lasted ca. 1 month. About 75% of dispersing larvae ballooned after making a bag. Settling velocities were determined for larvae with and without bags and trailing varying lengths of silk; a model was then developed that predicts dispersal distance for a particular wind speed and departure height. Most aerial dispersal is probably short-range. The bag reduced potential dispersal distance, but larvae with bags survived ca. 2 days longer than those without bags when exposed to abiotic factors off of a host. Larvae without bags ballooned mostly in morning, whereas 80% of the larvae dispersing with a bag ballooned in the afternoon. These patterns may be related to the diel periodicity of emergence of neonate larvae from old female bags, and the subsequent behavior of 1st instars prior to dispersal. A large proportion of each cohort emigrates regardless of host condition.

New genera Hirtodeceia, Marmarodeceia, Oncodometopus, Pachyopella, Poecilolycia, Trisapromyza, and Xeniconeura are described. The first two are exclusively Neotropical; the others occur also in the Nearctic Region. Relationships with other genera are discussed, and included species are listed. Homoneura (Euhomoneura) pictipennis Hendel is a preoccupied name, and the species is renamed and assigned to Marmarodeceia. Lyciella Collin is discussed, and L. rorida (Fallén) is recorded for the first time in North America.

In laboratory tests conducted under simulated stream conditions treatment with the insect growth regulator diflubenzuron at 1.0 mg/L/30 min at 15°C resulted in 100% mortality of Simulium larvae after 10 days. At 0.5 mg/L/15 min there was 97.6% mortality of S. vittatum larvae after 18 days in water at 10.5°C. Diflubenzuron was less effective when the growth rate of simuliid larvae during the test was slow due to inadequate nutrition, and it was more effective at 25 than at 20°C, but there was no difference in efficacy between 10 and 20°C. Efficacy against simuliid larvae varied inversely with their instar. Diflubenzuron at 1.0 mg/L/30 min was tested in the laboratory against selected nontarget invertebrates. Among the Ephemeroptera tested at 15°C, Baetis pygmaeus, Leptophlebia sp., and Isonychia sp. proved susceptible but not Stenonema fuscum and Ephemerella subvaria. Similarly diflubenzuron had little effect on the perlid stonefly Paragnetina media at 15°C and on the filter-feeding caddisfly Hydropsyche betteni at 20°C. Chironomid larvae (Phaenopsectra sp.) tested at 20°C were affected and the amphipods Gammarus pseudolimnaeus and Hyalella azteca were particularly susceptible at 25 but not at 15°C.

A key is given for 29 species in the subgenus Lambersius Olive in America north of Mexico. An annotated list is provided for 22 species, and descriptions for the following 7 new species: Uroleucon (Lambersius) carberriensis n. sp., U. (L.) clydesmithi n. sp., U. (L.) coloradensis n. sp., U. (L.) manitobensis n. sp., U. (L.) nevadensis n. sp., U. (L.) penderum n. sp., and U. (L.) suzannae n. sp. Uroleucon (Lambersius) tissoti (Boudreaux) is declared to be a synonym of U. (L.) luteolum (Williams) and U. (L.) baccharidis (Clarke) as a nomen dubium.

Larvae in the subfamilies and genera of Diprionidae in North America are described. Keys and illustrations are provided to aid in their identification.

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.

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.

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.

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.