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.

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 population densities of several major apple pests and their natural enemies were studied in an insecticide-free young bearing orchard and in an older orchard of semidwarf trees on an integrated control program. In mature orchards of standard size trees, greater natural mortality occurs than that reported in this study. Over a 5-year period most pests, with notable exceptions, increased rapidly under insecticide-free conditions whereas occasional numerical surges of certain pest species occurred under the mild insecticide program. Insect damage on fruit at harvest averaged 24% in the insecticide-free orchard and 8% in the integrated control orchard which had 2.4 times more harvested fruit.

Determination of the spatial pattern and estimation of the density of egg, larval, and adult populations of Ctenicera destructor (Brown) and Hypolithus bicolor Eschscholtz were made by soil sampling, and for C. destructor adults, also by cages that collected the emerging adults in the spring. Eggs of both the above species and also those of Aeolus mellillus (Say), which were also found in the samples, were highly aggregated. Small C. destructor larvae were most highly aggregated and medium larvae less so; large larvae were usually randomly distributed. Unlike C. destructor, large H. bicolor larvae were more highly aggregated than either the small or medium bicolor larvae. Sampling by emergence cages showed that C. destructor adults were aggregated while sampling by soil cores showed them to be randomly distributed. The different result obtained by the two methods was attributed to the difference in the size of the sampling unit. Aggregation was detected in 29% of the H. bicolor adult population sampled by soil cores only.

Larval densities of C. destructor ranged from a low of 0.25 to a high of 1.46 per sample unit (81 cm2) over the 14-year period that samples were taken; densities of H. bicolor ranged from 0.16 to 0.64. Densities of C. destructor and H. bicolor adults averaged about 6 (range 1–16) % and 12 (0–27) % of the total population of larvae and adults for each respective species. Population composition, in terms of adults and larvae of different sizes, and population fluctuations are discussed.

The relation between density and the number of sampling units required to achieve four levels of margin of error at four levels of statistical significance was determined.

No satisfactory transformation was found for data of individual samples with a mean less than 1. Several common transformations, including Taylor’s power transformation, were satisfactory for stabilizing the variance of pooled samples.

Larvae of bertha armyworm, Mamestra configurata Walk., collected in 1972–75 on rapeseed in the prairie provinces of Canada (predominantly in Manitoba), were killed by one virus, one fungus, one microsporidium, seven insect parasites, and by other factors. Mortality from disease was about 24% in 1972 when bertha armyworm was abundant, but much lower in succeeding years after the host’s population density declined. The most important hymenopterous parasite, Banchus fiavescens Cress., was relatively rare in 1972 but subsequently killed over 40% of the host larvae each year. A tachinid, Athrycia cinerea (Coq.), killed over 20% of the mature bertha armyworms in each generation. Each of the other five parasite species was associated infrequently with M. configurata. Details of the biology of each pathogen and parasite are presented. About 12% of the mature host larvae died because they failed to empty the gut, with subsequent penetration of the gut wall by bacteria, or because they did not form a morphologically-sound pupa. Pupae of M. configurata died in the soil following penetration of the gut wall by bacteria, as a result of soil cultivation, and from low temperatures in winter. No pathogens or parasites were recorded in field-collected pupae, though an ichneumonid, Ichneumon canadensis Cress., parasitized pupae in a field cage and may occasionally do so in natural conditions. No pathogens or parasites of bertha armyworm eggs were recorded. A preliminary survival model for bertha armyworm, based on estimates of mortality from various causes identified in this study, is presented. The possibility of preventing or reducing future oubreaks of M. configurata by colonizing additional parasite or pathogen species in the prairie provinces is discussed.

The larvae of Macrotheca angulalis Barnes & McDunnough and Alpheias sp. are described and illustrated. A comparison is made between these and the larvae of Galleriinae.

Adults of Trisetacus chamaecypari n. sp., and female adults of T. thujivagrans n. sp. are described, and species of Trisetacus associated with Cupressaceae and Taxodiaceae are discussed and keyed. An original diagnosis of the genus Trisetacus is included.

A population of the white fir needle miner, Epinotia meritana Heinrich (Lepidoptera: Olethreutidae), infesting white fir, Abies concolor (Gord and Glend.) Lindl., was studied in southcentral Colorado. Adults oviposited from mid-June through mid-August. Eggs were deposited on the concave side of needles, near the base. Larvae hatched in late July and August, then mined needles 1 or more years old before overwintering inside the first or second mined needle. In the spring, each larva mined one or two additional needles before pupating in the last needle during May or June. There was one generation per year.

White firs of all age classes were subject to defoliation, but tops of codominant trees were most heavily damaged. Oviposition occurred most often on 3–5 year old needles and larvae generally did not move to another year’s foliage. Apanteles (Braconidae) was the most prevalent parasitoid observed, causing about 11% larval mortality.

The compatibility of Bacillus thuringiensis (B.t.) with 27 chemical insecticides representing organophosphorus and carbamate insecticides, pyrethrins, chlordimeform, urea derivative, and antifeedant were studied by way of their effects on germination of the bacterial spores, replication of vegetative cells and spore staining, and refractive index characteristics.

The results showed that: (1) Carbamates were generally more compatible with Bacillus thuringiensis than were the other insecticide groups tested. (2) Technical formulations were less harmful to the bacteria than wettable powders which were less harmful than emulsifiable concentrates. (3) Of the 27 pesticides, those most compatible with B.t. were Orthene®, Dylox®, Lannate®, Sevin®, Zectran®, and Dimilin®. These insecticides are considered recommendable for use in integrated control operations with Bacillus thuringiensis if the target insects are susceptible to them and provided that due regard is given to the environmental implications of their use.

Probalaenifrons, n. gen., type-species P. argillacea, n. sp., from Buru, is described. Differential characters are given from the related genera Balaenifrons Hampson and Taurometopa Meyrick. Whalley’s provisional placement of these genera in the Odontiinae is confirmed. His suggestion that they might require a new subfamily because of their complicated tympanic structure is rejected, first because the genitalia are typically odontiine, and second because the only female of Taurometopa examined lacks the tympanic specializations, which are therefore either limited to the male sex or inconstant. The known species of Balaenifrons and Taurometopa are briefly discussed.

Ten insecticides, Bassa® [2-sec-butylphenyl N-methylcarbamate], Bioethanomethrin® [d-Trans ethano chrysanthemate of (5-benzyl-3-furyl) alcohol], carbaryl, diazinon, FMC 33297 [3-phenoxybenzyl (±) -cis-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate], methamidophos, oxamyl, parathion, SD 41706 [cyclopropanecarboxylic acid, 2,2,3,3-tetramethyl-, alpha-cyano-3-phenoxybenzyl ester], SD 43775 [benzeneacetic acid, 4-chloro-alpha (1-methylethyl)-, cyano (3-phenoxyphenyl) methyl ester], were tested against grasshoppers (second-instar Melanoplus sanguinipes) to compare their contact toxicities and their persistence on treated vegetation.

SD 41706, SD 43775, and Bioethanomethrin were more toxic than all compounds previously tested in this laboratory against grasshoppers. All three showed some persistence on treated vegetation after 1 day but only SD 41706 and SD 43775 showed persisting toxic effects on treated vegetation 3 days after spraying at the rates tested.

Field tests of (E)-11-tetradecenal and (E)-11-tetradecenyl acetate, the respective sex attractants for western spruce budworm, Choristoneura occidentalis Freeman and the Modoc budworm, C. viridis Freeman, revealed that these compounds attract several other forest Lepidoptera. The acetate attracted a total of 14 species representing seven families, and the aldehyde accounted for nine species representing four families. This interspecific attraction could influence budworm trapping efficiency and interpretation of results, because of the abundance of other responding species and the fact that two of the species resemble Choristoneura adults in appearance.

A model for intraspecific competition that incorporates the effects of inter- and intra-stage survival rates, spatial distribution, and variation in growth is developed using basic probability theory. Simulation results for cannibalism in Heliothis zea (Boddie) are presented and intraspecific competition is shown to have effects on population cyclicity and on mortality.

Formation of cocoons by larval Chironomidae has been reported in Endochironomus spp. (Sæther 1962), Hydrobaenus pilipes (Malloch) (as Trissocladius pilipes) (Hudson 1971), and Parakiefferiella sp. (Hudson 197 1). This is the first report of larval cocoons formed by a species of Eukiefferiella.

Dimilin® 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea is an insect growth regulator which disrupts the insect's molting process. It has been field tested against eastern spruce budworm, Choristoneura fumiferana, with variable results (Dimond 1975; Retnakaran et al. 1976). In addition to fluctuations in many field parameters, innate variations in susceptibility to Dimilin during different stadia may influence efficacy. Retnakaran and Smith (1976) found that larvae during the 5th and 6th stadia were most susceptible.

Many species of Lepidoptera, especially cutworms attacking forage, cereal, and oilseed crops, pupate in the soil. Most parasites leave their hosts after they enter the soil and so field collections are an excellent source of healthy pupae and parasite cocoons. Previous methods of obtaining adults involved collecting pupae by placing shovelfuls of soil on screens on a mechanical shaker and removing the exposed pupae. This was suitable for the harvesting of only a few dozen pupae as the capacity of the shaker was limited. A more efficient method of exposing them was required. We describe here a technique which we have used for large-scale collections.