Predation experiments were conducted to identify a predator with the capacity to control the tomato russet mite, Aculops lycopersici (Massee) (Eriophyidae), in greenhouse tomato crops. The efficiency of four predatory mites species was evaluated at the individual level in the laboratory: the tydeid Homeopronematus anconai (Baker) and the phytoseiids Phytoseiulus persimilis Athias-Henriot, Amblyseius cucumeris Oudemans, and A. fallacis Garman. The first three species had already been suggested as potential control agents. Predation by P. persimilis was essentially zero on tomato russet mite, whereas H. homeopronematus failed to develop to the adult stage when fed solely with this prey. Amblyseius cucumeris developed successfully on tomato russet mite but failed to reproduce. Only A. fallacis appears to possess several of the biological attributes required to control the tomato russet mite. This species attacks all stages of the pest and displays excellent survival (.92%), adequate rate of development (6.3 days at 22 °C), and good reproductive capacity in the presence of A. lycopersici.

The invasion of a Douglas-fir seed orchard by host-specific seed chalcids immigrating from the surrounding plantations of Douglas-fir has been monitored for a 10-year period. The orchard cone crop was entirely harvested every year to prevent the establishment of a resident chalcid population. Over the 10 years the percentage of infested seeds resulting from the immigration of seed chalcids ranged from 0.88 to 91.0%. A model to forecast the importance of annual seed orchard infestation by immigrating populations is proposed. This model is based on passive diffusion of females emerging in the surrounding plantations with a downwind drift. Only a few plantations located within a radius of 5 km from the orchard appeared to contribute significantly to orchard infestation. Settlement of Douglas-fir orchard in regions with low density of conspecific trees and annual harvest of cones are suggested to limit the importance and regularity of seed chalcid damage.

A survey of 65 populations of Colorado potato beetle, Leptinotarsa decemlineata (Say), from locations across Prince Edward Island in 1993 indicated that insecticide resistance was widespread, but was most prevalent in the western and central potato-producing areas. Of the populations surveyed, 31, 26, 19, and 4% were classified as resistant to permethrin, carbofuran, azinphos-methyl, and endosulfan, respectively. Of 53 populations surveyed for resistance to these four insecticides, 13, six, four, and one of the populations were classified as resistant to one, two, three, and four insecticides, respectively.

A commercial formulation of neem seed extract, Margosan-O, containing 0.3% AI azadirachtin, was tested under laboratory and field conditions against the European leafroller, Archips rosanus L. In laboratory tests, a 1% aqueous solution of neem insecticide produced 100% larval mortality within 48 h of treatment. At lower concentrations of 0.1 and 0.01%, 48-h mortality rates were reduced. Prolonged deleterious effects of sublethal treatments of neem were observed even at the lowest concentration (0.001%) tested. Mortality in the 0.1 and 0.01% treatments group reached 100% within 32–39 days after treatment. Field data showed that 3 weeks after application, 1% Margosan-O was as effective as the organophosphate insecticide diazinon and significantly more effective than the microbial insecticide Dipel (Bacillus thuringiensis). Larvae exposed to higher concentrations of neem died within 48 h after feeding on treated foliage. At lower rates, feeding deterrence (including cessation of feeding) and growth regulatory effects (e.g. difficulty in molting, abnormal larval growth, and formation of malformed pupae and adults) were recorded.

A chromatic mutation, dark body (mutants with a darker body than wild individuals), allowed us to test the effectiveness of the second mating in the bisexual species Trichogramma turkestanica Meyer, and of the first mating in the thelytokous species T. cordubensis Vargas and Cabello. Second mating in T. turkestanica was mostly efficient (i.e. followed by fertilization). Nevertheless, the latency before the second mating was longer as the time between second and first matings increased. The utilization of the spermatozoa from the second mating increased as the stock of spermatozoa from the first mating decreased. A long time in the presence of a male was necessary to obtain mating of the thelytokous females of T. cordubensis. Such fertilized females produced a low percentage (28%) of daughters from bisexual reproduction.

The antibiosis of crucifers to flea beetles, Phyllotreta cruciferae (Goeze), was compared for Brassica juncea L., B. napus L., and B. rapa L. with low antixenosis, B. carinata L. and Sinapis alba L. with moderate antixenosis, and Thlaspi arvense L. with high antixenosis. Adult flea beetles collected from the field in early spring fed actively on intact or excised leaves of all plants except T. arvense. The beetles survived, and gained weight and fat on the Brassica species and S. alba, but not on intact foliage of T. arvense. No antibiosis was detected in any of the Brassica species or in S. alba. Intact foliage of T. arvense was so antixenotic that beetles probably starved rather than suffered from antibiosis. A low level of antibiosis was detected in excised foliage of T. arvense where the antixenosis was lost. These experiments show that estimates of beetle survival, dry weight, and fat content can be used in the laboratory to test small numbers of candidate plants for antibiosis. However, the level of antibiosis appears to vary less among Brassica species and related plants than does the level of antixenosis, and so the latter is a more promising type of resistance for use against flea beetles in canola.

Four surveys of Bombus workers found on various flower species generated classifications of bumble bees according to tongue length and corolla depth of flower species. The long-tongued bees frequented species with long corollas and short-tongued bees frequented species with short corollas. Within-species analyses revealed several significant positive correlations between tongue length and corolla depth. The advantage of short tongues in bumble bees was investigated in an analysis of working speeds of different species on white clover, which has a short corolla. Bees with short tongues were more efficient than bees with long tongues.

Cylas formicarius (F.) shows a strong overall sexual monomorophism, with external differences noted in only three organs: (a) relative size of the hind wings; (b) form of the antennal club and numbers of its different types of sensillum; and (c) size of the compound eyes and their individual facets. We relate these to known or predicted behavioural differences. Eye dimorphism is used to test a theoretical rule on the relationship between differences in overall eye size and in the size of individual ommatidia. Some sexually monomorphic features are briefly discussed, including two types of putatively sensory hairs not found on the antennae.

Below-ground herbivores have been poorly studied regardless of their importance for the establishment and composition of plant communities. In a subalpine grassland associated with a 3200-m-elevation pine forest in central Mexico, the composition and vertical and horizontal distribution of the macroarthropod root-feeding community was studied for 14 months. The root-feeding community included six species of Coleoptera and one species of Diptera. The dominant species were Phyllophaga spp. (subgenus Phytallus, "macrophylla" group) and Trachyploeomimus aff. spurcus Champion. Mean density and biomass of this community were 101 individuals and 3 g per square metre, respectively. These values were low when compared with those reported for other communities. Species were most abundant in the first 10 cm of the soil all year around. Dominant species showed a clumped horizontal distribution most of the year.

A 5-year study of the black flies of east-central Saskatchewan revealed 21 species, including Simulium incognitum sp.nov. Chromosomal and ecological evidence for reproductive isolation is presented for this new species, formerly known as S. venustum Say CC4, and S. venustum Say CC. All 21 species in the study are associated with productive streams and rivers. As many as nine of these species might comprise the pest assemblage harassing livestock. The major pest, S. luggeri Nicholson and Mickel, is cytologically distinct from populations in the eastern United States on the basis of a two-step, Y-linked inversion in the IIS chromosomal arm. Simulium luggeri is the only livestock pest that breeds almost solely in large streams and rivers. The other eight probable pests breed entirely or partly in streams less than 10 m wide, often below beaver dams, suggesting that management efforts should specifically target these sites.

We here give Echinocoleus new ranking as a subgenus of Ptomaphagus. Ptomaphagus (Echinocoleus) acutus sp.nov. is described from the southeastern United States (Alabama, Georgia, Florida). It is the most plesiotypic member of a group in which all other species live in the western United States and (probably) adjacent Mexico. All are myrmecophilous with Pogonomyrmex and Aphaenogaster (= Novomessor) harvester ants. A phylogenetic analysis is given for the subgenus. The main synapomorphies of Echinocoleus, which are mostly interrelated with myrmecophily, are reduction of body length and broadening of elytra, reduction of antennal length, verticalization of mesocoxal insertion, reduction of mesosternal carina, body with a golden pubescense, and a pointed projection at the end of the spermatheca.

The nine species of the endemic North American Agabus seriatus-group are revised. All species occur west of the Rocky Mountains with A. lugens LeConte also occurring on the Great Plains and A. seriatus (Say) transcontinental in mid-latitudes. The species are placed in four subgroups, namely the seriates-subgroup with A. seriatus, A. lugens, and A. perplexus Sharp; the brevicollis-subgroup with A. brevicollis LeConte, A. pandurus Leech, and A. roguus new species; the ilybiiformis-subgroup with the single species A. ilybiiformis Zimmermann; and the regularis-subgroup with A. regularis LeConte and A. minnesotensis Wallis. Geographical variation in A. seriatus is analyzed and it is concluded that recognition of subspecies of A. seriatus is not warranted and A. s. intersectus (Crotch), NEW SYNONYMY, is relegated to a synonym of A. seriatus. For each species the following is provided: synonymy; description and illustration of taxonomically useful characters; notes on relationships, variation, distribution, and ecology; and a map of collection localities. A key to species is provided and lectotypes designated for A. brevicollis LeConte, A. lugens LeConte, A. perplexus Sharp, Gaurodytes suturalis Crotch (= A. lugens), and Ilybius regularis LeConte.

The oribatid fauna of commercial balsam fir [Abies balsamea (L.)] forests of western Newfoundland were surveyed through Berlese funnel extraction of samples taken from soil and various forest microhabitats. A total of 83 species or species complexes representing 39 families was collected. Fourteen genera and 36 species are new records for Newfoundland. One genus, Haplozetes Willmann, 1935, is a new record for Canada. For each species, notes on abundance in soil samples and distribution among microhabitats are provided and for the more abundant species, seasonal variation in abundance of immature and adult stages is plotted.

The efficacy of two production batches of conidia of Beauveria bassiana (Balsamo) Vuillemin that showed differential field efficacy in 1992 (GHA 92) and 1994 (GHA 94) were compared against grasshoppers in the laboratory and field. Conidia of GHA 92 and GHA 94 exhibited good germination (> 92%) by 24 h, but the rate of germination was slower for GHA 94 than for GHA 92. Although both conidial batches were highly virulent (LD50 < 6 × 103 conidia per nymph) against nymphs of Melanoplus sanguinipes (Fabricius) (Orthoptera: Acrididae) in the laboratory, GHA 92 was slightly more virulent than GHA 94. Conidia were applied to field populations of grasshoppers in a 1.5% emulsifiable oil-emulsion amended with 4% clay at a volume of 112 L/ha. There were no differences between GHA 92 and GHA 94 in the deposition of spray droplets on water-sensitive papers or of conidia on leaves and coverslips (2.4 × 10 to 4.1 × 10 cfu/cm2). All grasshopper nymphs collected from plots sprayed with conidia of GHA 92 and GHA 94 were equally infested with B. bassiana; conidial populations averaged 3.5 × 103 to 4.3 × 103 cfu/nymph. Conditions were hot, dry, and sunny, and regardless of the batch, persistence of conidia was equally short on both leaves and grasshoppers. Neither treatment of B. bassiana significantly reduced field populations nor did either impact differentially on specific grasshopper taxa. However, among grasshoppers collected immediately after conidial application and maintained in cages in the greenhouse, over 80% died of infection with B. bassiana. For both conidial treatments, the prevalence of disease in caged grasshoppers decreased with the sampling date but the onset of mycosis always occurred 3–4 days after collection. This study indicates that environmental conditions in the field and not pathogen virulence or targeting were responsible for the poor efficacy of B. bassiana against grasshoppers.

The carrot weevil, Listronotus oregonensis (LeConte), was monitored at 11 research or commercial carrot plantings at Holland Marsh, Kettleby, Ontario, using three methods, i.e. wooden plate (Boivin) traps to capture adults, carrot root sections placed in the soil to detect oviposition, and recording the numbers of adults present on carrot root sections. All three methods provided similar records of the seasonal pattern of adult activity. At most sites, thresholds used to determine the need for insecticide applications were reached or exceeded soon after the beginning of monitoring.

There were significant linear relationships among the seasonal activity parameters generated by the three methods and between those parameters and percentage injury at harvest. Control programs that would have resulted from the use of each method are discussed.

The forest tent caterpillar, Malacosoma disstria Hiibner, is widely distributed throughout North America and is subject to a variety of naturally occurring infectious diseases, including a nuclear polyhedrosis virus (NPV). NPVs have been isolated from several Malacosoma species in North America and Europe, including M. disstria, M. neustria, M. americanum, M. fragile, M. alpicola, M. californicum, M. pluviale, and M. constrictum (Stairs 1964). The viruses isolated from all North American species of Malacosoma may be cross transmitted from one species to another (Clark 1958). Distinctive isolates of NPV have been characterized from populations of M. disstria in Alberta (Keddie and Erlandson 1995) and Ontario (Ebling and Kaupp 1995).

The fir coneworm, Dioryctria abietivorella (Grote), is a major insect pest in seed orchards across Canada and the adjoining eastern and western United States. Larvae feed principally on cones, but they can also feed on needles and occasionally on the bark of young tree trunks (Hedlin et al. 1980; Ruth 1980; Martineau 1985). The potential for a population of D. abietivorella to build up in seed orchards may be greater than in natural stands (Hedlin et al. 1980; Ruth et al. 1982). The use of entomopathogen in the management of fir coneworm could be an adequate measure to reduce the impact of this insect. Moreover, Bacillus thuringiensis ssp. kurstaki has a specific effect on Lepidoptera (Aronson et al. 1986; Gill et al. 1992). The purpose of our study was to determine the activity of the HD-1 strain of B. thuringiensis ssp. kurstaki (serotype H-3a:3b) to larvae D. abietivorella. Bioassays were conducted with first-, third-, and fifth-instar larvae of fir coneworm to determine whether or not the insect's vulnerability to B. thuringiensis varies with larval age.

Bagworms (Lepidoptera: Psychidae) have an unusual life history (Borror et al. 1989). Following eclosion, apterous females stay within their pupal case and the protective bag they constructed as larvae. Females attract winged males by expelling pheromone-impregnated scales outside of their pupal case into the lower extremity of the bag. Sexual segregation of pupation sites has been found in three bagworms, Thyridopteryx ephemeraeformis (Haworth) (Gross andFritz 1982), Oiketicus kirbyi (Guilding) (Rhainds et al. 1995a, 1995b), and Metisa plarza (Mlker) (Rhainds, unpublished). In all three bagworms, proportionately more female than male larvae pupate in the upper strata of trees. Pupation of females in upper sites is adaptive because it may enhance any to all of the following: pheromone dissemination (Gross and Fritz 1982), mate attraction (Rhainds et al. 1995a, 1995b), progeny development (Rhainds, unpublished), and dispersal of neonatal larvae (Cox and Potter 1988). We report habitat segregation between male and female pupae of the bagworm Clania cramerii (Mstwood) (Thangavelu and Ravindranath 1985).

The legends of the tables were inverted. Consequently, the legend at the top of Table 1 on p. 594 should be above Table 2 on p. 602. Likewise, the legend above Table 2 should be above Table 1.