Attack and emergence of the engraver beetles Ips pini Say and I. latidens LeConte were measured in lodgepole pine (Pinus contorta var. latifolia Engelm.) naturally attacked by the mountain pine beetle, Dendroctonus ponderosae Hopk., in 1991. Sample trees were baited with the Ips pheromones ipsdienol and lanierone 1 week and 3 weeks after attack by the mountain pine beetle and again the following spring to observe the effects of the timing of bait placement. The densities of attack, egg gallery length, emergence, and hibernation of Ips species were measured. Ips latidens did not attack either the baited or unbaked trees at breast height until the spring of 1992 and the relatively low emergence was not significantly different by treatments. Among the 1991 treatments, the densities at breast height (1.3 m) of I. pini attack, egg gallery length, adult emergence in the fall of 1991, and numbers of hibernating adults in the duff were all highest for the 3-week treatment and lowest for the unbaked treatment. Significantly higher densities of beetles emerged and hibernated in the duff on the north sides of trees. Ips pini emergence in late summer 1992 from trees additionally baited in spring 1992 was significantly higher than for trees baited only in fall 1991. The density and temporal distribution of the emergence of both Ips species is discussed in relation to that of the mountain pine beetle.

Five species of Aphthona [A. cyparissiae (Koch), A. czwalinae (Weise), A. flava Guillebeau, A. lacertosa (Rosenhauer), and A. nigriscutis Foudras] were introduced into Canada for the biocontrol of spurge. Four identification keys are provided to determine these species: a field key based on the coloration of the body and appendages, a key for males using characters of the aedeagi, and two keys for females, the first based on features of the spermathecae, the second based on those of the styli.

The diapause response to photoperiod in Ontario populations of Cotesia melanoscela, an introduced parasitoid of the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), was investigated under a series of stationary photoperiods and constant temperature. When the parasitic larval stages of C. melanoscela were exposed to different photoperiods, the insect exhibited a typical long-day response: long days (greater than 18 h) promoted continuous development whereas short days (less than 16 h) resulted in diapause in the cocooned prepupal stage. Within the region of the critical photoperiod (16–18 h) the diapause response was associated with larval development time. Individuals that developed more slowly were more likely to enter diapause. Cotesia melanoscela was sensitive to photoperiod throughout its entire larval period. These individual responses are used to interpret patterns of seasonality of the parasitoid in Ontario and to compare with published information from populations of C. melanoscela in New England.

From 1989 to 1993, trunk implants of acephate were tested for the control of seed and cone insect damage to conifer species in France and northeastern China. The treatments were promising for the control of the major pests that feed on cone and seed tissues, including cone flies, coneworms, and seedworms, in European and Siberian larch, Norway spruce, Scots and mountain pine. In contrast, acephate implants did not prevent seed chalcid damage nor that of gall midges in Douglas-fir, European larch, and Siberian larch. Treatment generally increased seed yield, but a significant increase in the number of filled seeds was seen only when chalcids and midges were absent. The 2-year effect of implants seemed limited. Acephate implantation did not seem to affect seed germination.

Myzocallis (Neomyzocallis) pseudodiscolor sp.nov. from Quercus macrocarpa in North America, and Tuberculatus pilosulus sp.nov. from Quercus serrata in Japan are described. The affinities of the two species are discussed.

Four indicators of productivity and quality for the alfalfa leafcutter bee, Megachile rotundata (Fab.), were examined over a 3-year period and the influence of different shelter designs, nesting materials, and 34 environmental variables evaluated. A higher percentage of cocoons per total cells was produced in polystyrene nesting material than in pinewood nesting material. Both nesting materials had similar percentages of tunnels capped or containing cells and total numbers of cells per hive. Shelters with conspicuous orientation patterns or silhouettes had more tunnels capped per hive, tunnels with cells, and greater total cell production per hive than did other shelter designs. The time of maximum bee production varied greatly among the 3 years. Many environmental variables, especially those associated with higher temperature, heat units, and mean actual temperature, had a significant positive effect on bee productivity and cell quality. The information contained in this study may help delineate those climatic areas where this valuable alfalfa pollinator can be most effective, and may assist beekeepers in making management decisions that will improve their operations.

The relative toxicities of two formulations (Dipel WP and Foray 48B) of Bacillus thuringiensis Berliner var. kurstaki to the obliquebanded leafroller, Choristoneura rosaceana (Harris), were determined in the laboratory. The effects of application rate (BIU per hectare) and spray volume (litres per hectare) on the efficacy of Dipel WP and Foray 48B against C. rosaceana were determined in raspberry fields. Mortality of C. rosaceana increased with application rate, and decreased with an increase in spray volume. Bacillus thuringiensis exhibited significantly longer residual activity al higher application rates and at lower spray volumes. The half-life (time at which 50% of original activity remains) of B. thuringiensis ranged from 2.45 to 6.68 days, depending upon application rate and spray volume. Laboratory and field studies indicate that Dipel WP and Foray 48B are highly and equally effective in killing larvae of C. rosaceana.

Variability in vectoring efficiency among six clones of Rhopalosiphum padi L. and five clones of Sitobion avenae Fabr. in transmission of three French PAV isolates (PAV-RG, PAV-2t, and PAV-13t) of barley yellow dwarf viruses (BYDVs) on seedlings of barley (Hordeum vulgare L.) cv. Plaisant was determined. All the clones could transmit these three isolates, but their vectoring efficiency was significantly different: 91% and 56% transmission efficiencies were obtained from the most efficient clones (Rp-M and Sa-R1) but only 21% and 9% from the least efficient clones (Rp-R26 and Sa-V) with 5-day acquisition and inoculation access periods (AAP, IAP). A significant difference in overall transmission between apterous adults and winged aphids of the tested clones was also found. In most cases, apterous adults were more efficient than were winged aphids. The overall transmission efficiency of apterous adults was 1.5 and 1.7 times that of winged ones for R. padi and S. avenae, respectively. The transmissibility of PAV-RG and PAV-2t isolates was similar within each of the tested aphid clones, but that of the PAV-13t isolate differed, particularly for the poorly efficient vector clones of S. avenae. Temperature could significantly influence the vectoring efficiency of the tested clones of R. padi, but the influence was greater on Rp-R26. High temperature (25 °C) facilitated more transmission than did low temperature (14 °C), and high temperature for AAP played a more important role than it did for IAP.

The reproduction of Forficula senegalensis Serv. was studied in fields of bulrush millet (Pennisetum typhoides Burm.), 40 km south of Maradi, Niger. Flight activity, as determined by light trapping, follows a seasonal cycle in two phases: first the arrival of adults of the previous year in the fields at the onset of tillering; and second, the dispersal of adults of the new generation at the time of blooming and maturation of the plant, and their departure at harvest time. Females lay their eggs at the collar of the plants during tillering; hatching and nymphal dispersal occur soon afterward. From the second instar on, nymphs migrate to the intermediate and upper levels of the plant. The reproductive cycle of F. senegalensis thus appears closely synchronized with the development of bulrush millet.

The use of potato as a trap crop for the Colorado potato beetle, Leptinotarsa decemlineata (Say), in processing tomatoes was evaluated. The proportion of beetles counted on potato trap rows vs. the tomato crop on a per plant basis was 0.99, 1 week after transplanting, and never fell below 0.93 on any sampling date. In tomato plots that received no insecticides, potato trap rows placed as much as 16 tomato beds apart were effective in reducing beetle numbers on the tomatoes and producing crop yields 61–87% higher than plots without trap rows. Four of six pairs of plots had significantly fewer adult beetles and significantly higher tomato yields when a potato trap crop was present.

Gall inducers are favoured as biocontrol agents of weeds because they tend to have a narrow host range. Six insect and one nematode gall inducer used in Canada are described in terms of their biology, gall morphology, gall physiology, and effectiveness in weed control. The species differ in plant organ attacked, requirement for moisture, whether the galls are induced by secretions or by severing xylem, and effectiveness, which in part relates to the ability of the gall to import nutrients. The most powerful galls divert assimilates from other sinks via a gall’s vascular system joined to that of their host. One of our examples also has mechanisms to compensate for reduction of turgor during drought. Two of the gall inducers enhance their nutrient supply by severing xylem in a plant nutrient sink. One, in the short-term sink of a thistle capitulum, obtains about a quarter of its assimilates at the expense of other capitula. The other, in the long-term sink of a rosette root, approximately halves seed production. Hypotheses are presented to explain various aspects of gall development and function.

Galls induced by the aphid Tamalia coweni (Cockerell) were sampled from greenleaf manzanita (Arctostaphylos patula E. Greene) in Shasta County, California. Thirty galls from each of four sites were collected over a 5-year period (1990–1994) at roughly weekly intervals (N = 5010). The contents of each gall were examined and recorded. Excluding T. coweni, 25 taxa were encountered representing eight arthropod orders: Acari, Thysanoptera, Hemiptera, Neuroptera, Coleoptera, Diptera, Lepidoptera, and Hymenoptera. All play a minor role in the gall community with the exception of two species of Diptera. The data suggest that Leucopis sp. and Heringia sp. are obligatory predators of T. coweni and coexist by partitioning the aphid resource with different exploitation strategies. Heringia sp. has a relatively low infestation rate (10.8%) but is a superior competitor. Leucopis sp. compensates for its inability to compete effectively with Heringia sp. by maintaining a higher infestation rate (41.4%).

Although the structure of the ovipositor of parasitic Hymenoptera is largely uniform, interspecific variation in its morphology can be observed. Such variability may be related to the diversity of hosts attacked. To verify such an hypothesis, we compared, using correspondence analysis, the morphological characteristics of the ovipositors of 20 species in three categories: (i) species belonging to the same taxonomic unit and attacking the same type of host, (ii) species belonging to the same taxonomic unit but attacking different types of host, and (iii) species belonging to different taxonomic units but attacking the same type of host. Results show that variability in some morphological traits of the ovipositor can be related to host characteristics. Adaptive convergence in morphological variations observed between species is discussed.

Species of the Agabus opacus- and lineellus-groups, as defined by Larson (1989), are combined and revised as members of the A. opacus-group. The A. opacus-group contains 13 species, namely: A. hypomelas Mannerheim, A. vancouverensis Leech, A. verisimilis Brown, A. vandykei Leech, A. wasastjernae (Sahlberg), A. opacus Aubé, A. confertus LeConte, A. euryomus sp.nov., A. walsinghami (Crotch), A. jimzim sp.nov., A. lineellus LeConte, A. discors LeConte, and A. austrodiscors sp.nov. Agabus wasastjernae and A. opacus are Holarctic and boreal; the remaining 11 species are confined to the Cordilleran region of western North America. Character distribution does not support recognition of subspecies of A. hypomelas, therefore A. hypomelas irregularis Mannerheim is regarded as a synonym of A. hypomelas. A lectotype is designated for A. discors LeConte. A phylogenetic tree of the hypothesized relationships between the species is presented.

A key to the species of the group is included. For each species, the following information is provided: synonymy; description and illustration of taxonomically important characters; notes on relationships, variation, distribution, and ecology; and a map of North American collection localities.

Male spruce budworm moths were kept in a wind tunnel for 4 days and assayed each day to determine their ability to locate calling females that were surrounded by rubber septa loaded with synthetic pheromone, a 95:5 blend of E:Z-11-tetradecenal. As the concentration of synthetic pheromone increased, the numbers of males successfully locating females decreased, the latency of response increased, and the speed of flight decreased. At release rates from the septa close to those of a calling female, 6–60 ng/h per septum, most disrupted males flew to a septum instead of the females. At the highest release rate tested, 600 ng/h, many males were inactive or flew to the sides of the tunnel, which indicates sensory fatigue. This effect was more pronounced among males that were continuously exposed to the synthetic pheromone for the 4 days than among males kept in pheromone-free air between assays. About a quarter of the males died or became unable to fly after the 4 days, but there was no change in the proportions of the different responses of males, or in their response times, with increasing age, nor was there evidence that males were conditioned by their experience on previous days. The results led to the conclusion that time-averaged atmospheric concentrations of the synthetic pheromone as high as 20 ng/m3 are necessary to achieve effective disruption of the orientation of male spruce budworm moths to calling female moths.

Collections (68) of spruce budworm from 33 locations from Newfoundland to Alaska were analysed for isozyme frequencies using horizontal starch gels. Collections represented pre-, early-, mid-, late-, and post-outbreak stages of several populations in balsam fir, white spruce, and mixed host forests, as well as successive annual collections at several locations. Isozymes were measured at 11 loci in mature larvae and at six loci in pheromone-trapped males; frequencies were essentially the same in both stages, and from all host species. Three loci (IDH-2, LDH-1, and AAT-1) were found to be sex-linked, with no heterozygotes in females. Mean percentage heterozygosity ranged from 13.2 to 23.1; at individual locations it tended to decrease over successive years of outbreak and over successive collections in the same year. Contingency chi-square analysis indicated small differences related to location and outbreak history but all populations were generally homogeneous over the entire range. Nevertheless, one allozyme of AAT-1 exhibited a significant cline in frequency from the southeast to the northwest. Gene flow across the entire range appeared to be appreciable.

Atmospheric permeation of apple orchards with 16:1 butyl butyrate (BB): 2(E)-crotyl butyrate (CB), the sex pheromone of the mullein bug, Campylomma verbasci (Meyer) (Heteroptera: Miridae), demonstrated potential for pheromone-based mating disruption; atmospheric permeation with single components did not. In traps baited with 16:1 BB:CB, catches of male C. verbasci were 3, 64, and 105% of catches in nontreated controls for disruption treatments of 16:1 BB:CB, CB alone, and BB alone, respectively. With the two-component pheromone as a disruptant, catches of male C. verbasci were significantly reduced relative to controls at dispenser densities of 250, 500, and 1000 per hectare; catches were lowest at 1000 dispensers per hectare. For monitoring of operational trials, pheromone-baited open wing traps hung 1.5 m above ground were judged to be more practical than open wing traps hung 2.5 m above ground, or closed wing traps or white sticky cards at either height. Atmospheric permeation with pheromone did not affect numbers of males and females captured on nonbaited white sticky cards, and trap height did not affect catches of females. However, in pheromone-treated plots, significantly more males were captured on 2.5-m-high nonbaited cards than on 1.5-m-high cards, probably representing incidental catches of males following false trails to pheromone dispensers hung in the upper canopy. This study is the first reported example of pheromone-based disruption of orientation behavior in the Heteroptera.

Electrophoretic analyses of 12 loci on nine populations from Morocco, northern Spain, and southern France have revealed heterogeneity among localities (Fst = 0.064, Nm = 3.65) and a highly significant G test for polymorphic loci. The nine populations clustered into two groups on the UPGMA phenogram of genetic distances. Ecophysiological characters were examined (photoperiodic thresholds for diapause induction, development time, and number of larval instars at 25°C, under various photoperiods) for four of these populations. According to these ecophysiological characters, the populations could be divided into two groups congruent with those obtained with the genetic analysis. Although the species is known as being sedentary, we can put forward the hypothesis that insects could fly, not across the Pyrenees, but via the Atlantic or Mediterranean coast, thus creating a genetic flow between populations. Moreover, despite a larval diapause, the high mortality rate observed within certain subpopulations might contribute to genetic differentiation from residual populations surviving hard winters.

A 2-year field study was carried out to locate and identify eggs, determine the temporal distributions of eggs and larvae, and assess the impact of Strobilomyia laricis and S. viaria on Larix laricina. Eggs of S. laricis were beige with a patterned surface and usually laid one per cone in the bud scales at the base of the cone. Eggs of S. viaria were white and smooth and usually laid one per cone between the ovuliferous scales of the cone. Strobilomyia laricis oviposited from mid- to late May and S. viaria from late May to mid-June, each species initiating oviposition at a different stage of cone phenology. Peak egg densities of S. laricis were 25 and 65% higher than those of S. viaria in 1990 and 1991, respectively. Larvae of both species completed development at the same time, from mid-June to early July. The mean number of scales eaten per cone did not differ between species; one larva damaged a mean of 8.4 scales per cone in 1990 and 10.7 scales per cone in 1991. As the number of scales per cone increased, the mean number of scales eaten increased and the mean percentage of scales eaten decreased. Cone crops were light in both years. In 1990, the only year we were able to differentiate cone maggot larvae, 44% of cones were damaged by S. laricis and only 16% by S. viaria. Together, S. laricis and S. viaria damaged 60 and 67% of the cones and destroyed 38 and 50% of the potential seed crop in 1990 and 1991, respectively.

Allozymes at several polymorphic loci were assayed in larval collections of 12 recognized species and two possible new species of Choristoneura and two species of Archips. Most of the 48 collections came from high density populations, and those of C. fumiferana, C. occidentalis, and C. pinus represented much of the geographic range of these species. Mean percentage heterozygosity ranged from 2.0 to 18.6%, based on nine polymorphic loci. Three loci are sex-linked in C. fumiferana, two in C. pinus and C. occidentalis and probably in some other members of the group. Allozymes of aspartate transaminase (AAT-1) were most varied among the species and permit identification of individual C. fumiferana in better than 95% of cases. Among the group of coniferophagous Choristoneura species genetic distances were small (max. Nei = 0.232); C. fumiferana was the most distinct species. Wagner trees based on modified Rogers’ distances supported the above conclusions but indicated that separations among C. biennis, C. orae, C. occidentalis, C. carnana, C. subretiniana, and the two new species of Choristoneura were very small and probably below the species level, based on the allozymes measured.