Parasitoid studies were conducted concurrently with a pilot control project to test the efficacy of Dipel® WP, a formulation of Bacillus thuringiensis Berliner, in reducing western spruce budworm, Choristoneura occidentalis Freeman, populations. Twenty-one species of parasitoids were recovered in rearings of the budworm and an associated defoliator, the spruce coneworm, Dioryctria reniculelloides Mutuura and Munroe. Parasitoid population alterations occurred following application. Parasitism by Apanteles fumiferanae Vier. and Glypta fumiferanae (Vier.), which attack prediapausing first-instar budworm, was significantly higher in treatment blocks following B.t. application. Parasitism by Phaeogenes hariolus (Cr.), Cermoasia auricaudata Tns., and Madremyia saundersii (Will), parasitoids of late instars and pupae, was significantly lower following treatment. Comparisons of parasitoid populations were made between pre- and post-spray sampling periods and between treatment and check blocks.

Ten galls and pseudogalls caused by poplar gall aphids are described, their development discussed, and a key to their identification presented. Nine of these malformations are from Quebec poplars and one from Crystal Springs on Pigeon Lake, Alberta. All of the aphids involved belong to the family Eriosomatidae and sub-family Pemphiginae. Seven species are members of the genus Pemphigus Hartig, and of these P. bursarius (L.) and P. populitransversus Riley are well recognized economic vegetable pests in the United States. A monoecious species P. spirothecae Passerini is reported for the first time in North America. P. monophagus Maxson was collected from balsam poplars in Alberta. Other genera represented are Thecabius Koch (two species) and Asiphum Koch (one species).

The number of the birch casebearer larvae, Coleophora fuscedinella Zeller, within white birch crowns, Betula papyrifera Marsh., decreased 70% from overwintered survivors to about 50% pupae in the population. Within a crown, the highest number occurred in the outer shell and lowest in the inner. Casebearer numbers, weighted by the number of leaf clusters, were highest in the inner shell and lowest in the outer. Among crown quarters, both unweighted and weighted numbers were generally highest in the middle two crown quarters, lowest in the bottom quarter, and variable in the top quarter.

Peaks in immigration and emigration of larvae among crown strata occurred first when third and again when fourth instar larvae were most abundant. Immigration consisted only of intra-tree crawling, but emigration consisted of intra-tree crawling, removal by predation, and larvae leaving the tree to pupate on ground vegetation.

Three species of Hymenoptera comprise the guild of parasitoids utilizing alfalfa weevil, Hypera postica, larvae in Ohio. Where all three coexist, there has been a yearly increase in parasitization by Bathyplectes anurus and concomitant decreases in Bathyplectes curculionis and Tetrastichus incertus. We conclude that B. anurus dominance is due to its precise synchronization with peak host numbers, its high reproductive capacity, competitive superiority, and rapid search and handling. Domination of ephemeral hosts by such a parasitoid is in agreement with the general conclusions of Force, and Ehler and van den Bosch. B. curculionis and T. incertus compensate for imperfect synchrony with multivoltism and vagility (both spp.), aggregation and rapid search (B. curculionis), or random search and gregarious development (T. incertus).

Radessa n. gen. is described for R. vittilimbalis n. sp., the type-species, from Colombia and R. pardalota n. sp. from Panama. The genus is related to Omiodes Guenée, 1854, but has conspicuous, probably mimetic, orange and black maculation.

The insecticide acephate (0.5-dimethyl acetyl phosphoramidothioate) was applied at 0.5, 1.0, and 1.5 lb A.I./gal (.058, 0.118, 0.179 kg/l.) in aqueous solution to individual Douglas-fir trees infested with western spruce budworm, Choristoneura occidentalis Freeman, larvae in central Washington using hand held ground application equipment. Application was made when larvae were in the needle mining – bud mining stage at rates ranging from 2.58 to 5.10 gal/acre (3.97 to 7.84 l./ha). For all three concentrations, mortality of larvae inside needles was 94–98% after 1 day compared with a check mortality of 18% and larval mortality inside buds was 99% after 1 day compared with 23% for the check. Regression analyses indicated that defoliation was positively correlated with the number of needles mined the current year and per cent punctured buds, and negatively correlated with larval mortality inside both needles and buds. The data suggest that when applied at the rates used, acephate has some type of systemic action and can provide foliage protection during the year of application.

A new technique is described for remote monitoring of aquatic invertebrate populations which was specifically designed to eliminate effects on organism behavior attendant with other surveillance systems. Specifically, the system described overcomes the necessity for surgical implantation, restrictive weight, and the generation of unnatural activity.

Activities of a wide variety of aquatic invertebrates have been monitored using this system ranging in size from crustaceans of 300–600 μ long to dragonfly naiads of 3–5 cm long.

Immature Anax sp. and Somatochlora sp. were monitored for respiratory activity in relationship to decreasing oxygen tensions. An inverse relationship was observed between respiratory frequency and amplitude of respiration.

Fifteen life tables were compiled from population and mortality data collected in the Quinte area of eastern Ontario during the 5-year period, 1972–76, that spanned the rise and fall of an outbreak of the alfalfa weevil, Hypera postica (Gyll.).

Components analysis of the data showed that a disease of the feeding larvae caused by Entomophthora phytonomi Arthur, a fungus new to the insect in North America, was the principal determinant of intrageneration survival. Multivariate analysis of the separate mortalities, expressed as k-values, confirmed that this agent was the key factor governing population trends of the weevil and was mainly responsible for its population decline.

Examination of the properties of the various mortality factors showed that E. phytonomi was density dependent but overcompensating. Other agents, including the parasitoids Bathyplectes curculionis (Thom.) and Tetrastichus incertus (Ratz.) acted in a density independent manner and contributed little to population trend.

None of five mixtures of protein hydrolysate and azinphosmethyl which were applied as foliar sprays (1.0, 2.0, 5.0% yeast hydrolysate, 2.0% corn hydrolysate, and 2.0% soy hydrolysate) killed significantly more apple maggot flies, Rhagoletis pomonella, or black cherry fruit flies, R. fausta, than a spray of azinphosmethyl alone which was used as a control. This suggests that hydrolysate bait sprays would be no more effective than a toxicant alone in controlling these flies.

Evidence for competitive deplacement of Panonychus ulmi (ERM) from apple trees via Aculus schlechtendali (ARM) by what is thought to be a foliage conditioning mechanism is presented. Previous feeding of ARMs at high and moderate density levels near or below the economic threshold for this phytophagous mite on apple reduced the build-up of the ERM in 3 years of field experiments on Red Delicious trees and during a single season on McIntosh apple foliage. Comparative tests measuring oviposition rates of the ERM on excised apple leaves which had sustained high and low levels of previous rust mite feeding gave results similar to field experiments. The applied aspect of how this interspecific relationship can be managed in the context of an integrated mite management program for apples is discussed.

Life tables were constructed for populations of R. pomonella (Walsh) in two abandoned, heavily infested apple orchards near Como, Quebec. All life stages were sampled and the results expressed in terms of the apple as a unit. Twenty-five life tables, each based on one tree, covered two successive generations on both early and late maturing varieties.

Natality was of no value in predicting variation in numbers of emerging adults, whereas the early pupal stage estimates explained over 80% of the variation. Parasitism of larvae and pupae was more common than previously recorded but parasites were not significant in the population dynamics of their host. Nutritionally based larval mortality, predation on mature larvae and pupae, and movements of adults between trees were key factors in population variation. Early variety trees appeared to maintain apple maggot population levels. These results were supported by experimental studies on the effects of temperature treatments and predation on larval and pupal mortality.

Juvenile hormone, the secretion of the corpus allatum, apparently controls the secretory process of the male accessory glands of the yellow fever mosquito, Aedes aegypti. Topical application of a juvenile hormone mimic induces precocious and enhanced secretion. The treatment with the JH mimic not only increases the potency of males to inseminate more numbers of females, but also stimulates secretion in fully depleted glands of A. aegypti which under normal conditions do not renew the secretory process. Males whose accessory glands are depleted due to multiple matings and later treated with the mimic also inseminate. Cauterization of the corpus allatum complex has prevented the secretory function in the glands.

A key is given for 37 species of Aphis L. in Manitoba. Three new species of Aphis are described, duckmountainensis, neomonardae, and whiteshellensis. Aphis monardae Oestlund is declared to be a synonym of A. gossypii Glover. Lectotype and paralectotypes are designated for A. rubicola Oestlund. Comments on taxonomy and biology are given for other species in the genus.

The North American Diparinae (Pteromalidae: Chalcidoidea) consists of six genera and 11 species, of which eight species are described as new. These are Trimicrops bilineatus, T. trilineatus, Dipara pedunculata, Netomocera nearctica, Lelaps floridensis, L. beckeri, L. melinus, and L. striatus. Illustrated keys to genera and species are provided.

The larvae of Tetralopha web leaves of many kinds of trees and shrubs. A key to nine North American species is included, with descriptions of the last instar larvae. The species considered are Tetralopha robustella Zeller, T. militella Zeller, T. expandens Walker, T. aplastella Hulst, T. asperatella Clemens, T. vacciniivora Munroe, T. euphemella Hulst, T. scortealis Lederer, and T. baptisiella Fernald.

Detailed laboratory studies of mated spruce budworm (Choristoneura fumiferana (Clem.)) show that the number of eggs per day, mean cluster size, and mean wet weight of the eggs gradually decrease during the period of oviposition of individual moths. The term mean weight of initial eggs (Ei) is defined and compared with other measurements of mean egg weight based on total egg complement or parts of it. Ei is 6%–12% greater than the mean egg weight based on all eggs laid. In spite of variation in pattern of egg weight distribution among moths, Ei appears to express satisfactorily the differences in mean egg weight among moths and can be used to survey egg weights among populations.

Laboratory rearing studies of individual clusters indicate slightly slower emergence rates (seconds from hibernacula), greater survival, and smaller proportions of male pupae in the third and fourth quartiles of the egg complement; there were no differences in pupal weights related to cluster order. There is no ready explanation for this improved survival of larvae from eggs known to be smaller.

Implications of these results for the population dynamics of the spruce budworm are discussed. The more stressful conditions encountered in the natural environment may counteract the apparently better survival of individuals from the latter part of the egg complement.

Spruce budworm infested stands of white spruce and balsam fir were aerially sprayed with an entomopox virus, a nuclear polyhedrosis virus (NPV), a low dose of fenitrothion, and the two virus–chemical insecticide combinations. Long-term assessment of the efficacy of the treatments showed that NPV + a low dose of fenitrothion suppressed the budworm population density particularly on balsam fir below that causing economic damage for 3 years due mainly to transmission of the virus from one generation to the next and maintenance of natural control agents in the population.

Parasitism by Apanteles and Glypta spp. on spruce budworm in five localities in Quebec in 1975 was exceptionally high, averaging 52%. The frequency distribution of attacks of these species, and the outcome of inter- and intraspecific progeny competition are described, using dissection data. Superparasitism occurred on a Poisson distribution, but rates of multiparasitism lower than expected indicate interference between Apanteles and Glypta spp.

The predaceous mite Balaustium putmani Smiley was studied in the laboratory and in apple orchards in southern Ontario. A rearing technique was devised which facilitated the study of the life history and behaviour of individual mites.

Temperature and moisture influenced the development and hatching of eggs. In the presence of water, development proceeded more rapidly at the higher temperature of the 10°–25°C range tested. In the absence of water no development occurred. Larval B. putmani are free-living predators and although some were observed feeding periodically on pollen grains, they could not survive solely on this diet. All three motile stages are predators of a wide range of small, soft-bodied arthropods, but feed mainly on eriophyids and phytophagous tetranychid mites. The rate of consumption of the eggs and motile stages of the European red mite was determined for each motile stage at 20° and 25°C. Insemination is by externally deposited spermatophores and in the adult females, no facultative parthenogenesis was evident.

The principal developmental stages and the female reproductive system of Grypocentrus albipes Ruthe are briefly described and illustrated. The oviposition pattern is described. Females chew through the leaf tissue and gnaw on Fenusa pusilla (Lep.) larvae while the larvae are in their larval mines. The average fecundity in laboratory experiments was 3.2 eggs per day, and the maximum number of eggs deposited by one female was 96. Some observations are presented on egg and larval development as well as on pupation.