The larvae of 17 species of Hydroporus Clairville were described and characterized; a key for their discrimination and illustrations of structural features of first- and third-instar larvae are provided. Many structural features, especially those of chaetotaxy and porotaxy of head capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for taxonomic and phylogenetic comparisons. Based on 21 larval characters, the phylogenetic relationships among the five main lineages of Hydroporus (s. lat.) occurring in North America were studied. Structurally, the species of the subgenus Hydroporus (s. str.) and of the vilis species-group (H. planiusculus Fall) were found to be the most generalized taxa whereas the subgenera Neoporus Guignot and Heterosternuta Strand encompassed the species with the most derived condition. The subgenus Heterosternuta was closely related to the subgenus Neoporus and both subgenera were hypothesized to form a distinct monophyletic unit on the basis of five synapomorphies. The only representative of the oblitus species-group studied, H. paugus Fall, was related to Hydroporus (s. str.) and the vilis species-group by the shape of the siphon. This species was a very peculiar clement within Hydroporus (s. lat.) because it was the only known species of the genus without stemmaia in the first- and second-instar larvae, with stemmata greatly reduced in size in the third-instar larvae, and with a secondary dorsomedian seta on antennomere 2. The larval features of Hydroporus (s. lat.) were compared with those of Hygrotus Stephens. The comparison suggested that both genera form a monophyletic unit, that each of them is a distinct monophyletic unit, and that Hydroporus (s. lat.) is the sister-group of Hygrotus Stephens.

Daily patterns of host-seeking activity by female tabanids were determined by hourly trapping (0530–2230 hours) with Manitoba horse fly traps at Seven Sisters, Man., 4 days a week, throughout the summer of 1988. Hybomitra epistates (Osten Sacken) and H. pechumani Teskey and Thomas were most active during late morning or mid-day; H. arpadi (Szilady) and H. zonalis (Kirby) in early afternoon; H. affinis (Kirby), H. illota (O.S.), and H. lasiophthalma (Macquart) in late afternoon; H. nitidifrons nuda (McDunnough) and H. lurida (Fallen) in early evening.

The morning onset of tabanid flight activity usually was related to temperature, but the cessation of activity in the evening was related either to temperature or light, depending on which was first to fall below threshold levels. Tabanid flight activity was generally low at temperatures below 20°C, although H. lasiophthalma and H. affinis occasionally were caught at 12°C. Little flight activity occurred at light intensity levels below 1000 lx regardless of temperature. At Churchill, Man., where tabanids were trapped hourly from 27 July to 15 August in 1988, H. affinis and H. frontalis (Walker) activity was low below 14°C, although some activity occurred at 6°C.

Seventeen species of the genus Otiorhynchus are known to occur in North America (including Greenland) (O'Brien and Wibmer 1982; Wibmer and O'Brien 1989). Warner and Negley (1976) provide a key to 16 species (not including O. monticola Germar, since recorded from Greenland) and provide information on distribution and natural history. All species occurring on mainland North America are known to be introduced. Whereas some of the species have broad distributions in North America, for example O. ovatus (L.), others are known from only a few adjacent localities. Species such as O. singularis (L.) and O. sulcatus (F.) are found in both western and eastern North America but not in intervening areas. Such distributions likely represent separate introductions.

The feeding behavior of adult Colorado potato beetles has been studied on leaflets from two clones of Solanum berthaultii Hawkes (PI473340, clones #1726 and #1729) and on S. tuberosum L. var. Norchip leaflets treated with leaf extract from S. berthaultii 1726. Treatment of S. tuberosum leaflet with leaf extract from S. berthaultii 1726 (0.075 mg/cm2 of leaflet) did not modify the behavior of adult Colorado potato beetles even if consumption was reduced. On S. berthaultii 1726, consumption and consumption rate were reduced, the frequency of the “moving” behavior increased, the frequency of the “resting” behavior decreased, and the frequency of the “feeding” behavior did not change compared with S. tuberosum. The antifeedant property of S. berthaultii 1726 probably was perceived during the sampling step of the feeding behavior and prevented continuous feeding.

The beetles avoided contact with S. berthaultii 1729 leaflets, less consumption occurred, the frequency of the “feeding” and “resting” behaviors was reduced, and the “moving” frequency increased in most cases. This suggested the presence of deterrents influencing host acceptance and initiation of feeding. On S. berthaultii 1726 and 1729, the frequency of some behaviors changed during the bioassay (2.5 h in duration), probably as a consequence of food deprivation.

A European microphysid, Loricula bipunctata (Perris), is reported as new to the Nearctic Region. The only other member of the genus recorded from North America, the Palearctic L. pselaphiformis Curtis, also is adventive in our fauna (Kelton 1980)

In May 1990, the carabid beetle fauna of an urban Edmonton, Alta., garden was sampled by hand, and specimens were identified using Lindroth (1968). The most common carabid in the garden was Acupalpus meridianus (L.). Other carabid species found in the same small area included: Carabus nemoralis Müller, Clivina fossor (L.), Amara familiaris (Duftschmid), A. apricaria (Paykull), Agonum placidum (Say), and Pterostichus melanarius (Illiger). All of these except A. placidum are introductions from Europe (Spence and Spence 1988).

Many cone and seed insects exhibit a dormancy in which the individuals may undergo a diapause that lasts 1, 2, or more winters and the proportion of 1-year diapause (1YD) and 2-year diapause (2YD) varies from year to year (Hedlin et al. 1980). Thus, segregating the two diapause types carries a practical importance for forecasting the attacking adult population in a given year. Based primarily on teleological reasoning it has been argued that insects committed to a longer dormancy may have higher weights with metabolites to sustain survival for a longer period. Individual weights have been examined with the hope of separating 1YD from 2YD individuals.

A spruce budmoth population reduction of 82%, as measured by moth emergence, was realized after a foliar spray in which Futura®, a commercial Bacillus thuringiensis Berliner (B.t.) formulation, was added to a suspension of Steinernema carpocapsae (Weiser). The nematode suspension, which took advantage of the wetting and spreading agents in the formulation, was applied to runoff at the rate of 9785 viable infective juvenile nematodes per litre. Mortality was attributed to the nematodes; B.t. was not available to the cryptic larvae. Soil drench treatments were encouraging, and suggested that applications of nematodes to the soil may be feasible.

A mating suppression bioassay, an electroantennogram study, and a lure attractancy study demonstrated the sensitivity of the Croesia curvalana (Kft.) moth to the female sex pheromone. Mating suppression of 98% was achieved with source concentrations of 30 μg of either (E)- and (Z)-11-tetradecenal (95:5) or the natural pheromone blend of (E)- and (Z)-11-tetradecenal (90:10) + (E)- and (Z)-11-tetradecenyl acetate (85:15) (aldehyde:acetate = 9:1), and was 60% with a source concentration of 0.6 μg. Source concentrations of the minor component acetate, ranging from 15 to 0.6 μg, produced mating suppressions of from 78 to 38%. Male antennae responded to source concentrations of 2 × 10−10 mg (E)- and (Z)-11-tetradecenal (90:10) and antennal saturation occurred at 2 × 10−4 mg. Little female response was found at any age. Polyvinyl chloride lures releasing 1–2 ng/h captured males at approximately the same rate as did virgin moths. Release rates as low as 8 ng/h reduced trap capture from the 4 ng/h release rate found to be most effective under prevailing environmental conditions using Pherocon 1C traps. Results from these studies suggest C. curvalana could be a candidate for pheromone-based field mating suppression.

Combinations of Bacillus thuringiensis Berliner subspecies kurstaki and Beauveria bassiana (Balsamo) Vuillimen formulated on granules were applied separately and in combination to field corn to suppress larval populations of the European corn borer, Ostrinia nubilalis (Hübner). Research was conducted in 2 separate years. Laboratory-reared O. nubilalis eggs or larvae were placed on the plant during either the whorl stage (V6) or the pollen-shedding stage (R1) to simulate first- and second-generation O. nubilalis oviposition periods, respectively. Efficacy was determined by measuring the length of European corn borer tunnels in the corn stalk at harvest time. In the 1st year, first generation, and second generation (of 2nd year) B. thuringiensis and B. bassiana alone and in combination caused significant reductions in tunneling compared with that in the check populations. There were no significant differences in tunneling between any treatments in the second-generation study of year 1. Bacillus thuringiensis and B. bassiana were independent of each other in their suppression of insects. Tunneling by the naturally occurring second-generation larvae (year 2) was recorded to determine if B. thuringiensis and B. bassiana applied in the V6 stage persisted in the plant. Pith samples were excised from nodal plates 7–10 of the corn stalk to determine the incidence of B. bassiana. There was a significant correlation (r = −0.376) (P≤0.05) between the occurrence of B. bassiana in the corn plant and tunneling by second-generation larvae. These data indicate that B. bassiana placed in the whorl of the corn plant may provide season-long suppression of O. nubilalis.

Early season infestations of adult tuber flea beetles, Epitrix tuberis Gentner, usually are concentrated at the edges of potato fields, and it generally has been assumed that they move into potato fields from the outside inward. This edge-effect suggests that tuber flea beetles overwinter outside potato fields, and other species of flea beetles have been reported to behave similarly (Wolfenbarger 1940; Dominick 1971; Burgess 1981). This may not be true of E. tuberis, however. Hoerner and Gillette (1928), in Colorado, noted that potatoinfesting flea beetles [probably E. cucurneris (Harris), E. subcrinata (Lec.), or E. tuberis] often congregated under piles of old potato vines in potato fields, and Hill and Tate (1942) observed flea beetles feeding on cull tubers in a potato field after harvest. These observations suggest, but do not confirm, that some flea beetles including E. tuberis may remain in harvested potato fields during winter.

Corn rootworm (Diabrotica spp., Coleoptera: Chrysomelidae) is a serious pest insect of corn production. It is estimated that farmers in the United States have losses of over $1 billion each year as a result of crop damage and treatment costs for this pest (Metcalf 1986). Chemical control is the main method of suppressing corn rootworm populations and the amount of insecticide used against Diabrotica spp. is greater than for any other pests of corn in the United States (Suguiyama and Carlson 1985). The development of nontoxic and biodegradable alternatives to chemical insecticides is highly desirable.

The genus Dalbulus (Homoptera: Cicadellidae) consists of 11 species, 10 of which can be found in México (Nault 1990). Some members in the genus, such as the corn leafhopper, Dalbulus maidis (DeLong and Wolcott), and the Mexican corn leafhopper, Dalbulus elimatus (Ball) are serious pests of maize due to their transmission of three corn stunting pathogens: corn stunt spiroplasma (CSS; Spiroplasma kunkelii Whitcomb et al.), maize bushy stunt mycoplasmalike organism (MBSM), and maize rayado fino virus (MRFV) (Nault 1990). Due to the widespread damage that these leafhopper-vectored pathogens cause in maize-growing regions in Latin America, a search for the leafhopper natural enemies was conducted in maize agroecosystems in central México.

Codling moth, Cydia pomonella (L.), is a major pest of apples, pears, and certain stone fruits and tree nuts. Alternatives to conventional insecticides are needed to manage codling moth infestations in the field and after harvest. In an earlier evaluation of codling moth ovipositional behavior on stone fruits, “Queen Ann” plums were found to be highly acceptable (Yokoyama and Miller 1988). We present preliminary testing of plum fruit volatiles for effect on the ovipositional behavior of codling moth, with emphasis on the ovipositional deterrent activity of 1-nonanol.

Allozyme and morphological variation were investigated for mountain pine beetle populations in limber pine and lodgepole pine in Alberta and British Columbia. Fourteen gene loci, five of which were polymorphic, were studied. Heterozygote deficiencies were detected at the ME locus for 13 of the 16 groups of beetles sampled. Selection against heterozygotes appears to be the most plausible explanation. There was no significant difference in heterozygosity between beetles from lodgepole pine and those from limber pine. Relatively high levels of genetic differentiation, in terms of allele frequency, were observed among beetles from different sites, host species, seasons, and individual conspecific trees within a site. Low levels of differentiation were observed between beetle generations at a site and between sexes. We attribute significant host-associated genetic differentiation to differential survival in hosts rather than to differential host preference of beetle genotypes. Standardized discriminant function analysis of 12 morphological characters indicated significant differences in beetle shape between sexes, host species, and among sites. Overall, there was little evidence of preferential host selection by beetles which would imply substructuring of Dendroctonus ponderosae Hopkins populations along host lines.

Sympatric, synchronous populations of conifer-feeding Choristoneura (Lepidoptera: Tortricidae) occur in western North America (Powell 1980). Choristoneura occidentalis Freeman, the western spruce budworm, co-exists with C. retiniana, the Modoc budworm, in mixed stands of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and true firs, Abies spp. Choristoneura occidentalis has brown larvae and a broad geographic distribution associated with one of its principle hosts, Douglas-fir (Stehr 1967). Larvae of C. retiniana are green and feed on true firs, particularly white fir, Abies concolor (Gord. & Glend.) Lindl. (Stehr 1967; Carolin et al. 1987).

Agapeta zoegana L. (Lepidoptera: Cochylidae) is a Eurasian root-mining moth introduced into North America for control of spotted knapweed, Centaurea maculosa Larnarck. The biology and host specificity of the moth were described by Müller et al. (1988, 1989). Early-instar larvae mine the epidermal tissues of the root crown. Older larvae mine the root cortex and endodermis and cause considerable damage, especially to small plants or when several larvae infest a single large plant. Larvae can migrate below ground to a new host plant if the initial knapweed plant has been destroyed. The moth overwinters as a larva in the root and emerges as an adult in June through August. Several generations per year may occur.

While studying the types of the Crambinae in the National Museum of Natural History, Washington, DC, I came across an odd-looking specimen with a crambine facies but with a very faint wing pattern unlike any crambine I had ever seen. A note that it was probably a member of the Pyraustinae (Pyralidae) had been written by A.B. Klots on the label of the female genitalia slide (prepared by Carl Heinrich on 30 August 1930). Closer examination showed that the tympana1 organs were of the pyraustine type, with the praecinctorium bilobed. Upon my request, E.G. Munroe examined the specimen and discovered that it belonged to the genus Udea Guenée in the Pyraustinae. The specimen is the type of Platytes aenigmatica Heinrich (1931), a species described in the Crambinae (Pyralidae). It is here transferred to the genus Udea as Udea aenigmatica (Heinrich), new combination. Because this name was classified incorrectly, the species was not treated by Munroe (1966) or included in Munroe (1983).

First detection of the Russian wheat aphid, Diuraphis noxia (Mordvilko), in the United States occurred in March 1986 in the Texas panhandle. Within 3 years, this aphid pest was found in 15 western states and three provinces in Canada. Each year since 1986, Russian wheat aphid has been responsible for millions of dollars in grain loss and insecticide treatment costs (Anonymous 1988, 1989). Physiological responses of the plants to the aphid include chlorotic streaking, rolled leaves, entrapment of developing seedheads, stunting, reduced tiller production, and reduced yields (Hewitt et al. 1984; Johnson et al. 1988; unpublished data).

Microdon albicomatus Novak are obligate temporary myrmecophiles, passing their immature life in the nests of ants. Second and third larval instars are aggressive mimics of ant brood (Garnett et al. 1985). Larvae physically and chemically (Garnett et al. 1985; Stanley-Samuelson et al. 1990) resemble the ant cocoons upon which they prey and are transported with the ant brood by the worker ants.