Three sequential-sampling plans were developed for adult Diabrotica barberi Smith and Lawrence and D. virgifera virgifera LeConte in field corn in southern Ontario. The distribution of both species was well approximated by the negative binomial distribution and obeyed Taylor’s power law. Two plans, following the methods of Kuno (1969) and Green (1970), estimated populations with predetermined precision. The third plan, based on Wald’s (1947) sequential probability ratio test, categorized populations relative to an economic threshold. Different sequential-sampling plans were constructed for 1st-year fields and for all other fields because the parameter k, measuring the extent of aggregation of the beetles, differed between these two classes of fields. Decision equations for Wald’s plan in 1st-year fields were: D1 = 0.98n − 17.75 and D2 = 0.98n + 13.82. Decision equations for 2nd-year or older fields were: D1 = 0.99n − 13.42 and D2 = 0.99n + 10.45. The use of Wald’s plan reduced the required sample size by 55% in 1st-year fields, and by 48% in all other fields. The savings associated with the other sequential-sampling plans were not significant.

Today methyl bromide is being used throughout the world to control insect pests. Intrinsically it is not among the most toxic of insect fumigants, but it has a combination of properties which gives it an unique position among gaseous insecticides. Of particular importance are its powers of penetration and its non-inflammability under normal fumigating conditions. Methyl bromide is important also as the leading fumigant in a group, the halogenated hydrocarbons, which includes other widely used fumigants such as ethylene dibromide, ethylene dichloride, and ethylene chlorobromide.

The effect of long-term storage on the activity of biological control products, particularly those containing nuclear polyhedrosis viruses (NPVs), has not been extensively studied. Most investigations involving viral insecticides have dealt with their thermal stability (Stuermer and Bullock 1968; Dulmage and Burgerjohn 1977; McLeod et al. 1977; Ignoffo and Couch 1981). Freeze-dried and air-dried powdered preparations of gypsy moth, Lymantria dispar L., NPV show little reduction in potency after storage at 4°C for 10 months and 3 months, respectively. Consequently, it was recommended that gypsy moth NPV be stored in either state at 4°C to maintain acceptable activity (Lewis and Rollinson 1978). TM BioControl-1, the viral product for control of the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), registered and used in the United States, has been shown to have a shelf life of 5 years if stored in a cool, dry place (Martignoni 1978). Virtuss is the NPV product manufactured in Canada, in the whitemarked tussock moth, O. leucostigma (J.E. Smith), since 1975 by the Forest Pest Management Institute, Forestry Canada, Sault Ste. Marie, Ont., for the control of the Douglas-fir tussock moth. It is routinely stored at 4°C in anticipation of tussock moth outbreaks and has been successfully used in the control of outbreaks of Douglas-fir tussock moth in Canada (Otvos et al. 1987). If these, or any other viral products are to be successful commercially, more information is required on the effect of storage on viral potency. Similarly, little information is known of the cumulative effects of the mechanical processes of lyophilization and milling on the biological activity of viral products. This note reports on the effects of mechanical processing and storage on Virtuss. Our results show that, although there is no immediate effect of mechanical processing, there can be substantial loss of biological activity of this product after 2 years of storage.

Prionomitus mitratus (Dalm.), Trechnites insidiosus (Crawford), Pachyneuron sp. and Asaphes probably vulgaris Walker are recorded as parasitic in Psylla pyricola L. The first two are primary parasites, the latter two are hyperparasites. All are new records for British Columbia. The biologies of T. insidiosus and Pachyneuron sp. are discussed briefly.

In tests of bacteria pathogenic for defoliating insects, previous workers used water suspensions of the microorganisms and contaminated the foliage fed to the insects hy dipping or spraying (1, 2). Where a quantitative result is sought such procedures have some limitations. The waxy cutin present on leaf surfaces, and this is especially true of the foliage of coniferous trees, encourages the formation of surface droplets and makes it extremely difficult to achieve uniform spreading of the bacterial suspension. In addition; the cutin interferes with the adhesion of the dried suspension to the leaf surface. To overcome these difficulties, certain adhesive agents, such as peptones, milk solids, albumin, etc., have been used, but these too are open to objection. If it is desired to reproduce as closely as possible a natural infective process, the use of protein products introduces a new variable and occasionally renders the foliage unpalatable to the insect.

Direct observation (DO) of arthropods on soybean plants was compared with another absolute method, clam trap (CT), and with sweepnet (SW) sampling during a season-long investigation of the colonization by arthropods of two east central Illinois soybean fields. In terms of number of species detected, DO vs. CT showed good agreement between the two fields, while DO vs. SW showed poor between-field agreement. Proportion of similarity (PS) and quotient of similarity (QS) values were higher in a DO-CT comparison than in a DO-SW comparison. Performance similar to that of the other absolute method, consistency of results, ability to use the method throughout the entire season, relatively high numbers of species and individuals detected per unit area sampled, relatively short time required to sample a site, and the capability of yielding a precise record of important interactions among soybean arthropods indicate that direct observation is an effective method for sampling the arthropod community on a row crop such as soybean.

Representative aquatic insects, larvae of Simuliidae, Chironomidae, Trichoptera, Megaloptera, and nymphs of Ephemeroptera and Plecoptera, were tested for susceptibility to continuous exposure to Bacillus thuringiensis Berliner var. kurstaki at 4.3, 43, and 430 IU/mL. Only Simulium vittatum was affected, and at the highest concentration. Effects on other organisms, particularly Prosimulium fuscum/mixtum, were suggested. The lowest of the concentrations tested was twice the worst-case transitory concentration peaks expected in water from aerial forest spraying at 30 BIU/ha. Spray buffer zones around water bodies are unnecessary at this spray rate.

The following new species are described to make names available for publications by other entomologists.

Apanteles salalicus n.sp.

This keys to couplet 72 or 74 in Muesebeck's revision (Proc. U.S. Natl. Mus. 58: 483-576, 1921.) but differs from both species there in its solitary habits, strongly exserted ovipositor sheaths, large and acutely pointed hypopygium, elevated and very coarsely sculptured abdominal tergites, and yellow hind coxae.

In an attempt to evaluate the importance of physical and biotic factors affecting the distribution of species of the cutworm genus Euxoa, a multivariate regression analysis, as based on a light-trapping survey in western North America, has been conducted. The possible contributory factors have been grouped into four major categories relating to geography, habitat, period of flight, and sample size. Sample size is a composite value reflecting both suitability of habitat and suitability of weather conditions at the time the sample was taken. Geographic factors considered were latitude, altitude, and longitude; habitat factors were mean annual temperature, mean July temperature, mean January temperature, mean annual rainfall and plantform; factors relating to period of flight were calendar date, mean temperature on date of sample, photoperiod, and the phenological date. Except for photoperiod, the variables listed were considered in a quadratic as well as a natural function in the regression analysis. With the number of species of Euxoa as the dependent variable and the factors listed above as the independent variables a total reduction of 76.0% in the residual variance was obtained. When only four variables, sample size, mean annual temperature, mean annual rainfall, and phenological date were employed in a similar regression analysis, however, a reduction of 68.7% in the residual variance was obtained. On the basis of present evidence, it appears that temperature and rainfall are primary factors governing the abundance of species of Euxoa in a given habitat.

A variety of wild and domestic mammals from Manitoba were examined for external parasites, and fleas were recovered from 15 species. A total of 17 species of fleas were collected, of which 10 were first records for Manitoba, one was a subspecies new to the area, and 7 were recorded from new hosts. Orchopeas leucopus and Monopsyllus wagneri were the most abundant species taken from wild animals, being found on the most abundant host, Peromyscus maniculatus. Flea populations reached a peak in late summer, and were found in greater numbers on juvenile than on older hosts, on lactating than on other adults, and on solitary than on gregarious species.

Four steinernematid strains, Steinernema carpocapsae All strain, S. carpocapsae Umeå strain, S. feltiae Lie strain, and S. feltiae strain 27, were evaluated in laboratory and field tests as potential agents for the control of the black army cutworm, Actebia fennica (Tauscher). Although each of the six instars was susceptible to attack, incidences of infection were highest and generally over 60% for the third, fourth, and fifth instars when exposed to 100 infective juvenile nematodes in petri dishes. Fifth-instar larvae exposed for 1 week to soil containing 4000 infective juveniles in a 1:1:1 mixture of the L1c, All, and Umeå strains were most frequently infected with the L1c strain when reared at 10 and 12 °C and with the All strain when reared at 14 and 16 °C. One hundred thousand infective juveniles of the L1c, All, and Umeå strains and strain 27, alone and in various combinations, and applied by either a spray or soil-plug inoculation, killed black army cutworm larvae caged in the field for 1 week with treated black spruce seedlings and provided protection of current and 1 -year-old foliage. Treatments that included strain 27 provided the best protection when daily mean soil temperatures were 7–11 °C in comparison to treatments that included the Umeå or All strains, whereas treatments that included the All strain as a component appeared to be more effective than treatments containing the L1c and Umeå strains when daily mean soil temperatures were 16–17 °C.

In my neighbourhood I find the typical Andrena Cressonii, Rob., and the form described below as A. dubia, the latter more rare. To compare this with the form described as A. Bridwellii,Ckill., I have obtained from Mr. Bridwell for examination thiry-three specimens taken by ghim at Baldwin, Kansas, and labelled A. Cressonii, A. Kansensis, and A. Bridwellii.

A. Kattsensis is the same as A.Cressonii, the colour of the pubescence being characteristic of unfaded specimetrs. Local specimens sometimes have the hind tibiæ and tarsi ferruginons in both sexes.

The clover seed midge, Dasyneura leguminicola (Lint.), is one of the most important pests in red clbver seed fields in Ontario wherever the double-cut varieties are grown. The larvae feed within the clover florets, destroying the ovaries; if numerous, they prevent many fields from producing seed crops worth harvesting. In 1951 and 1952 and to a lesser degree in 1953, severe damage occurred in seed fields in eastern Ontario (Guppy, 1958); since then populations of the insect have gradually declined. British Columbia, Quebec, and New Brunswick are the only other provinces in Canada from which damage has been reported. However, the insect probably occurs wherever red clover is found in Canada.

Mayflies of the genus Ameletus (Ephemeroptera: Ameletidae) occur in practically every drainage of western Alberta and in the Cypress Hills, from headwater spring brooks to larger rivers. The genus is speciose and reaches its greatest diversity in the southwestern part of the province where as many as 12 species can occur at a single site. Of the 30 bisexual species currently recognized from North America, 13 have been collected from Alberta (A. bellulus, A. celer, A. cooki, A. majusculus, A. oregonensis, A. pritchardi, A. similior, A. sparsatus, A. subnotatus, A. suffusus, A. validus, A. velox, and A. vernalis), and another, A. inopinatus, is assumed to occur in the northern part of the province. Male adults of all North American species were described previously by Zloty (1996, The Canadian Entomologist128: 293–346). In the current paper, we describe late-instar larvae and adult females of all 14 Albertan species, and provide species distributions and keys for identification of male and female adults and larvae. All diagnostic taxonomic characters are described and illustrated. The identification keys can also be used in Saskatchewan, eastern British Columbia, Montana, and the northern parts of Idaho and Washington.

Five genera, Annegialia new genus, Bdelyropsis Pereira, Vulcano, and Martinez, Callosides new genus, Fossocarus Howden, and Scarabaeinus Silvestri, are discussed. Four are monotypic, Annegialia ataeniformis n. sp. from the western United States, Callosides campbelli n. sp. from Colombia, Fossocarus creoleorum Howden from the southern United States, and Scarabaeinus termitophilus Silvestri from Brazil. In the last two genera, the male of Fossocarus is described for the first time, and in Scarabaeinus information on the range and host is given. A second species of Bdelyropsis, newtoni n. sp., is described from Veracruz, Mexico, and a brief discussion of B. bowditchi (Paulian) is included.

An apparatus consisting of a plastic box and a feeding circuit permits the calculation of μl volumes of ethanol ingested by Drosophila melanogaster Meigen. The net amount of ethanol taken (expressed in 100% ethanol) has been examined in various experimental conditions: sucrose solutions, ethanol–sucrose solutions at various sucrose and alcohol concentrations, ethanol solutions - cube of sucrose and ethanol solutions alone. The data obtained on ingestion by Drosophila show that the consumption of sucrose solutions was inversely proportional to the concentrations of sucrose. The amount of ethanol ingested during 14 days was directly related to the concentration of ethanol in the diets although in general the total volume of solution consumed did not vary significantly in most cases. The analyses of observations of 14 days showed that decreased mortality was obtained with the rise in the concentration of sucrose in sucrose-water solutions in 0.5–3% range and the mortality increased with the rise in the concentration of ethanol in the diets, yet ethanol-sucrose was better than cube of sugar alone.

The effects of sequential attack on gallery construction, oviposition, and reemergence by Dendroctonus frontalis Zimmermann were studied in the laboratory at 25 °C. Six mating pairs were allowed to attack bark slabs in groups of 2 pairs every 2 days. Total gallery and eggs per pair decreased with increasing day of attack. The time of attack had little effect on the distance and time from the gallery origin to the first egg. Distances between eggs were shortest for pairs attacking second and greatest for pairs attacking last. Inverse relationships of egg-bearing gallery length, oviposition period, and adult residence time were observed with the day of attack.

The basic behavioral and physiological mechanisms thought to influence reproduction of D. frontalis are discussed. A hypothesis for termination of oviposition is formulated from these mechanisms, which provides greater understanding of the effects of attack density on reproduction.

Observations on the occurrence of Camnula pellucida (Scudder) on native grasslands in Saskatchewan indicated that such areas did not support large populations of this species except on the margins where these were adjacent to cereal crops. This supports the view that large-scale infestations arise when both a food habitat (cereals) and an oviposition habitat (short grass) are readily available to the insects.

Nosema acridophagus Henry was shown to be more virulent than N. cuneatum Henry to 3rd-instar nymphs of Melanoplus sanguinipes (Fab.) following peroral inoculation with 1.0 × 106, 105, 104, or 103 spores/individual. The lethal time was dose dependent and significantly shorter and the lethal dose (LD50) was significantly lower in grasshoppers inoculated with N. acridophagus than for those inoculated with N. cuneatum. Grasshoppers inoculated with N. acridophagus died earlier and a smaller proportion survived to the adult stage compared with those inoculated with N. cuneatum. Nosema acridophagus was more infectious at the lower doses than was N. cuneatum; however, N. cuneatum reached an intensity of infection in host tissues which was 2–10 times higher. Both microsporidians appeared to have similar pathogenicity for both individually and group-reared M. sanguinipes.