Nine species of parasites and one hyperparasite were reared from a complex of the brace spanworm, Operophtera bruceata (Hulst), and the European winter moth, O. brumata (L.), collected in the Victoria area of Vancouver Island, British Columbia, in 1976 and 1977. Parasitism of the host complex was about 1.5%, mainly due to an unnamed species of Phobocampe (Ichneumonidae). All species of parasites taken in British Columbia on the two hosts have congeneric counterparts on O. brumata in Europe as listed by Wylie (1961); thus the release of exotic species in addition to the two already released in British Columbia may not enhance the biological control of O. brumata. Descriptions and illustrations of cephalic structures of final-instar larvae of the parasites and a key for their separation are given.

Adoption of the term “tonofibrillary platelets” for the small, sclerotized areas of muscle attachment on the cuticle of Lepidoptera larvae is advocated and a simplified system of abbreviations for the names proposed by Mutuura (1980) for these areas is suggested.

Ten species of black flies were collected from the Souris River, Manitoba between April 1977 and October 1978. Adults of Simulium luggeri Nicholson and Mickel, Simulium meridionale Riley, Simulium venustum Say, Simulium verecundum Stone and Jamnback, and Simulium johannseni johannseni (Hart) were collected feeding on livestock and humans, and are well known pest species. Simulium vittatum Zetterstedt was the most abundant species, but was not a pest on man or domestic animals. Simulium tuberosum (Lundström) and Simulium johannseni duplex Shewell and Fredeen were the least abundant species. Simulium j. johannseni, S. j. duplex, S. venustum, S. verecundum, S. tuberosum, and Cnephia dacotensis (Dyar and Shannon) appeared to be univoltine species while S. luggeri, S. meridionale, Simulium decorum Walker, and S. vittatum were multivoltine in the Souris River.

An evaluation of cone, plate, rope, and wire cage sampling devices for black fly larvae and pupae indicated that cone samplers provided a more representative sample for population assessment.

In a black fly control program, of the Souris River, Manitoba two separate larvicide treatments in spring may be necessary. In the case of two treatments, the first should be aimed at late instar larvae of S. j. johannseni, S. venustum, and S. verecundum. Since the majority of S. luggeri and S. meridionale would be in the egg stage at this time, a second treatment, 10–14 days later, would be necessary to control late instar larvae of these species.

Host foliage was evaluated for nonpreference and antibiosis by field rearing Douglas-fir tussock moth larvae, Orgyia pseudotsugata (McDunnough), (instars 2–6) at typical outbreak and non-outbreak forest sites in central California. Nonpreference was evaluated by comparing frass production and antibiosis by comparing survival, pupation, and fecundity on the different sites. Typical outbreak sites had a lower site index and higher plant moisture stress than typical non-outbreak sites. Production of frass for all crown levels collectively was not significantly different between sites, although more frass was produced in the tops of trees on outbreak sites. Survival and pupation were also not significantly different between sites, but egg production was 28% higher on outbreak sites than non-outbreak sites. If differences in foliage quality did exist between sites, they did not affect the tussock moth enough to explain observed differences in population numbers.

Larvae of the chironomid Nanocladius (Plecopteracoluthus) branchicolus Sæther were found living phoretically with nymphs of the stonefly Acroneuria lycorias (Newman). The male and fourth instar larva of N. (P.) branchicolus are described for the first time. The stonefly and chironomid were found in streams in central and northern Saskatchewan forests. Of six Saskatchewan Perlidae species, the chironomid was associated only with A. lycorias. The chironomid most often occurred beneath stonefly wing pads. In the laboratory chironomid pupation lasted about 2 days with emergence occurring about 2 days prior to stonefly emergence.

Dissections of eggnests of brood XIV, 17-year periodical cicadas (Magicicada spp.) confirmed earlier reports that most eggs do not hatch when the host twig is so damaged that it withers, breaks and dies, i.e., “flags”. However, the proportion of eggs hatching in experimentally broken twigs is intermediate between the proportions hatching in flagged twigs and in live twigs. Evidently, the developmental stage of the egg at the time of twig breakage is the major factor reducing hatching success.

Some of the vigorously growing branches respond to oviposition damage by secreting resin or forming callous tissue, which imprisons many eggs, preventing them from hatching. The data suggest that ovipositing cicadas have developed an oviposition strategy that both maximizes the number and percentage hatch of eggs laid per twig, and reduces the incidence of flagging and host defence responses. Large aggregations of ovipositing females may weaken the host plant and prevent it from responding. On the other hand these aggregations increase twig breakage. However, the proportion of twigs broken is reduced by each cicada species using somewhat different twig sizes, by the smaller species adjusting eggnest structure to fit the twig size used, and by all females positioning their eggnests along the twig in such a way as to avoid overlap.

The number of large embryos in adult Macrosiphum euphorbiae (Thomas) was investigated in 1974–77 as a means of forecasting population trends on field tomatoes. In an incubator the embryo count (e) of apterae and alatae was related to the daily birthrate (N) by the equation N = 0.45 e + 0.33, except in the first 4 days of adult life of the apterae. On field plots of tomatoes, e was only satisfactory for forecasting population trends in 1 of 4 years of observations. This probably occurred because the adults were mainly apterae. The relationship between flights of alatae and populations on tomatoes appeared to differ from year to year. In 1974 the number of alatae in large populations in tomato plots was more closely related to the number of alatae trapped in flight with a suction trap in the week after than in the week before the tomatoes were sampled, suggesting many alatae were leaving the tomatoes. In 1975–77, populations on tomatoes were low and the number of alatae on the plots was more closely related to suction trap catches in the week before than in the week after the counts on tomatoes, suggesting many of the alatae on the plots had recently arrived there. The percentage of alatae among adults on field tomatoes declined with days from planting each year. Red forms always constituted ≥ 50% of populations on tomatoes and in flights, the rest being green.

Male release-recapture experiments show that under natural photoperiod there is no cross attractancy between species of the sympatric pairs E. declarata and E. campestris or E. declarata and E. rockburnei, but that there is between the parapatric pair, E. campestris and E. rockburnei. When the calling periods of E. declarata and E. campestris females are synchronized by photoperiod manipulation there is cross attraction between these two species as well. However, in mating discrimination tests between E. declarata and E. campestris the normally strong bias against interspecific mating is only partially overcome by synchronizing mating activity rhythms. The residual tendency for conspecific mating is more likely due to imperfect synchronization of mating rhythms or differences in close range courtship behavior than to differences in attraction pheromone. Males of all three species are attracted to the same synthetic attractants. The results are consistent with the hypothesis that the attraction pheromones of the three species in the declarata group are very similar and are unlikely to play a major role in reproductive isolation, which is probably effected primarily by differences in circadian rhythms of mating activity.

Two species of the genus Sesioplex Viereck of North America are revised. One new species, californicus, is described, the other, depressus Viereck, is redescribed. The limits of the genus are redefined and a key to adults is provided. The important taxonomic features of both species are illustrated by line drawings.

Damage to honeysuckle (Lonicera spp.) has been associated with Hyadaphis tataricae (Ajzenberg), an aphid species of European origin previously unknown in North America. A survey indicated that H. tataricae is present throughout much of the Province of Quebec. Marked differences were observed in the degree to which various species and cultivars of honeysuckle were attacked, in both the Montreal Botanical Garden and the van den Hende Garden in Quebec City.

Variables affecting the efficacy of seven juvenile hormone analogues on western spruce budworm, Choristoneura occidentalis Freeman, were examined in laboratory bioassays. Those tested were epofenonane, hydroprene, kinoprene, methoprene, triprene, ZR-587, and ZR-1662. Selected intrinsic variables—stage of development, sex, and extent of direct contact with sprays—were examined in bioassays involving direct exposure of third instars, direct applications to three pupal age classes, and indirect applications to sixth instars. An extrinsic variable, persistence in the environment, was assessed by determining the residual effectiveness of each juvenile hormone analogue to sixth instars. Sixth instars, rather than third instars, appeared to be the target of choice for two reasons. First, less active ingredient would be required for equivalent mortality by the time of adult eclosion. Second, greater, more consistent, deleterious reproductive effects coupled with a lower incidence of sexual variation in lethal effectiveness, would occur. Pharate pupae and untanned pupae were very susceptible to most of the chemicals and may provide a secondary target for the primary target, sixth instars. The importance of direct chemical-insect contact in achieving maximum reproductive inhibition suggests that these chemicals might be used most effectively in ways such that contact can be maximized, as in ground applications. Finally, some juvenile hormone analogues such as epofenonane and ZR-1662 appeared to persist long enough to permit flexibility with respect to instar distribution in a population.

A series of field experiments using large field cages were used to evaluate the role of aphidophagous predators on the population dynamics of the pea aphid, Acyrthosiphon pisum (Harris), on alfalfa, Medicago sativa L. The pea aphid numbers increased rapidly in the cages to as much as 5 times the density in the adjacent fields. The difference between densities in the cage and field decreased as the season progressed. No significant differences in fecundity of the aphids were found either in clip cages in the field and cages, or in the laboratory using field-collected aphids that were allowed to larviposit for 24 h. We used an earlier simulation model of the aphid to show that if fecundity alone were responsible it would have to be 3 times the maximum rate we have ever observed. The return of the aphid density to the field value when one cage was removed and the aggregation of predators show the importance of predator movements in limiting prey numbers.

The relationship between posttreatment temperatures of 15°, 20°, 25°, and 30°C and toxicity of six pesticides to adult female Phytoseiulus persimilis Athias-Henriot and Tetranychus urticae Koch were studied in the laboratory.

The toxicities of cyhexatin, dicofol, propargite, citrazon, chlorobenzilate, and per-methrin were positively correlated with temperature. Except for propargite and permefhrin, P. persimilis was less susceptible than T. urticae at 15° and 20°C, but equal in susceptibility at 25° and 30°C.

The results obtained may indicate a potential value of posttreatment temperature manipulation as a useful adjunct to integrated pest control programs in glasshouses.

Intensive sampling for eggs of Aedes vexans (Meigen) in upland wet-prairie habitats revealed that three species of plant, Echinochloa crusgalli (barnyard grass), Polygonum pennsylvanicum (smartweed), and Cyperus esculentus (yellow nutgrass), commonly occurring in contiguous U.S.A. and southern Canada and dense mats of vegetative detritus could be used as indicators of oviposition sites. Where a slope was steep, specific elevations indicated oviposition site preferences. Plant species and elevation were both indicators of areas where soil moisture was attractive to gravid females. Soil moistures between 55% and 69% were found optimal for oviposition.

When 95% ethanol was sprayed at the rate of approximately 46 ml/m2 of bark surface on the lower 1 or 2 m of standing living spruce trees, Picea engelmannii Parry – P. glauca (Moench) Voss hybrid population, 23 of 47 and 18 of 19 treated trees in two areas received one to many spruce beetle, Dendroctonus rufipennis (Kirby), attacks, whereas only 2 of 63 and 2 of 64 untreated trees, respectively, were attacked. Some of the treated trees were killed by mass attacks of the beetles, but most trees pitched out the attacks. Thus beetle attacks on essentially resistant trees were induced by the ethanol treatment. However, spruce beetles were not attracted by the ethanol treatment.

Field experiments tested lineatin, the aggregation pheromone of Trypodendron lineatum (Olivier), in combination with either S-(+)- or (±)-sulcatol, the pheromones of Gnathotrichus retusus (LeConte) and G. sulcatus (LeConte), respectively. Beetles of each species responded maximally to their own pheromone alone or in a binary combination. Slight, but significant cross attraction between Gnathotrichus spp. was evident, and G. retusus was slightly attracted to lineatin. Both Gnathotrichus spp., but not T. lineatum, responded to α-pinene with ethanol. These two compounds had no effect on the allelochemic activity of the pheromones. While mutually inhibitory communication would be of adaptive advantage in bark beetles which compete for an essentially 2-dimensional host, the phloem tissue, little selection pressure would occur among ambrosia beetles which share a more bountiful host, the 3-dimensional sapwood; hence the lack of mutual inhibition between Gnathotrichus spp. and T. lineatum. On the other hand, enantiomer-based specificity in pheromone communication between Gnathotrichus spp. may have been at least a partial basis for speciation. Compatibility of lineatin with either S-(+)- or (±)-sulcatol indicates that in pheromone-based pest management, 2-binary pheromone stimulus release systems can be used instead of 3 single ones.

The spread of Thymelicus lineola (Ochsenheimer) in North America has been extensively documented (Rawson 1931; Clench 1956; Pengelly 1961; Arthur 1966; Burns 1966; McNeil et al. 1975; McNeil and Duchesne 1977). In Canada, T. lineola has been recorded from British Columbia, Ontario, Quebec, New Brunswick, Nova Scotia, Newfoundland, and now Manitoba (Gregory 1975; Jackson 1978). In the north central United States T. lineola has been recorded from St. Louis Co. and International Falls, Minnesota (Brewer 1977; Lundeen 1980). Pengelly (pers. comm.) observed T. lineola at Dryden, Ontario in 1972. McCabe and Post (1977) did not include this species in their list for North Dakota. The purpose of the present note is to report on the presence and collections of T. lineola in Manitoba and in northwestern Ontario.

Pine oil, a by-product of sulphate wood pulping, protected pheromone-baited, living Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl.), and spruce (Picea glauca (Moench) Voss - P. engelmannii Parry hybrids) from attack by Douglas-fir beetle (Dendroctonus pseudotsugae Hopk.), mountain pine beetle (D. ponderosa Hopk.), and spruce beetle (D. rufipennis (Kirby)), respectively. Pine oil also protected surrounding trees and reduced attack incidence on Douglas-fir, lodgepole pine, and spruce within at least a 10 m radius. α-Terpineol, one of the constituents of the pine oil mixture, was less effective.

The flight range of Culicoides variipennis was studied in a bluetongue virus enzootic area during the summer of 1977. Field-collected larvae and pupae were reared to the adult stage in a field laboratory. Approximately 82,200 flies were marked with micronized fluorescent dusts and released and 403 were recaptured in CO2-baited baffle traps. The maximum distance traveled was 0.8 km by a male and 4.0 km by a female. One female was recovered on the release night 2.8 km from the release point. The mean distance traveled (MDT) was 0.8 km on the release night, 2.02 km on one night postrelease, and 2.11 km on two nights postrelease. The MDT for all flies recovered up to eight nights postrelease was 1.89 km.

Based on the overall MDT of 1.89 km, the transmission of a disease agent by C. variipennis becomes theoretically possible if the host population density is greater than one per 3.57 km2. The probability of transmission can be significantly reduced if a 3.57 km2 area surrounding a single C. variipennis breeding site is treated with an effective insecticide.

Phenological events associated with control of San Jose scale (Quadraspidiotus perniciosus (Comstock)) in deciduous tree fruit orchards of the western United States were modeled, using the Predictive Extension Timing Estimator (PETE). The model closely simulated adult male activity and first crawler emergence, although spring male emergence was too variable to rely entirely on accumulated degree days from 1 January for management decisions. Pheromone monitoring of spring males improves timing for control of subsequent crawlers when a biofix of 275°D from 1 January is used.