Laboratory wind tunnel and field observations have demonstrated an important behavioural role of tetradecanal (14:Ald) in the chemical communication system of the spruce budworm, Choristoneura fumiferana (Clemens). A greater number of males initiated upwind flight and continued on to contact the source when 14:Ald was present than with 95/5 E/Z11-tetradecenal (E/Z11-14:Ald) alone. The presence of E11-tetradecen-1-ol acetate (E11-14:Ac) decreased the males' responsiveness to the aldehydes. Its effect appeared to be attenuated, when present at low levels with 95/5 E/Z11-14:Ald, by the presence of 14:Ald, but it is still unclear what effects low levels of E11-14:Ac have on male behaviour.

Populations of the western spruce budworm, Choristoneura occidentalis, were sampled in western Montana, central Idaho, and eastern Oregon. In 22 of 24 populations, the proportion of females among pupae did not differ from 0.5. Similarly, in 21 of 24 populations, the proportion of females among adults was not different from 0.5. In all populations, differences between survival rates of male and female pupae were attributed to chance. The proportion of females among pupae (a) did not differ between insects on Douglas-fir and those on grand fir, (b) was slightly but significantly higher among insects in the mid-crown than among those in the lower crown, and (c) was significantly higher among the insects in the one site studied where average defoliation of current-year shoots was greater than 50%. Variation in the proportion of females among adults should have a negligible effect on the dynamics of these populations.

Local dispersal and survival of male spruce budworm, Choristoneura fumiferana (Clem.), moths under field conditions was determined by mark, release, and recapture in pheromone-baited traps. Recapture rates and distance of recapture were dependent upon height of traps and proximity of traps to the release point, but over 65% of those recaptured were caught within 50 m. With traps 20 m apart, 30% of the recaptures were in traps farthest from the release point (50–70 m), a fact which suggests that male spruce budworm may disperse beyond this distance at low densities. Males were recaptured up to 7 days after release, and had a daily survival rate averaging 67%.

The Nearctic species of the genus Trichacis are revised. Nine out of 15 species recognized are new to science: T. alticola (New Mexico, Colorado), T. bison (Ontario, Florida, Louisiana, Illinois, Texas), T. celticola (Mississippi, Ontario, Louisiana, Texas), T. dracula (Illinois), T. elongata (Missouri), T. huberi (California), T. mandibulata (Illinois), T. pyramidalis (Ontario), and T. striata (Florida). Six previously described Nearctic species are redescribed, viz. T. arizonensis (Ashmead), T. cornicola (Ashmead), T. cornuta Fouts, T. rufipes Ashmead, T. texana Fouts, and T. virginiensis Ashmead. The males of T. arizonensis, T. texana, and T. virginiensis are described for the first time. A generic diagnosis of Trichacis and keys to Nearctic species are given. The higher classification, bionomics, world distribution, and character states of Trichacis species are discussed.

Population density and parasitism of larch casebearer, Coleophora laricella (Hübner), were monitored for 10 years before parasites introduced for biological control became abundant. Overwintering densities remained fairly stable at about 100 larvae per 100 buds. The factor most closely correlated with population change was something, as yet unknown, other than the native parasites, which tended to be inversely density-dependent. The data will serve as the “before” period in a before and after evaluation of the biological control program.

The mean weights of the initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), vary within and between populations. Measurements of collections from across the range of this species reveal the presence of a cline directly related to latitude and longitude of the collection source. Collection mean Ei values range from 0.219 mg in the northwest to 0.157 mg in the southeast. A similar cline, also related to latitude but negative in slope, is demonstrated for the number of eggs per unit pupal weight. This cline also finds expression in changing slope of fecundity/pupal weight regressions. The cline in egg weight appears to be an adaptation to winter conditions across the range of this insect and should be considered in population dynamics.

Laboratory studies of the mean weights of initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), show that this value is determined by the genetic constitution of the female moth and is relatively independent of environmental control. Dietary differences experienced by the female during larval development, and originating from different hosts or from reduced nutrient levels in artificial diets, did not affect Ei values; however, depletion of nutrients sufficient to reduce fertility greatly did reduce Ei. Temperature conditions during the ultimate larval and pupal stages influence Ei values which vary inversely. Mean egg weights are strongly heritable and are readily selected for, thereby demonstrating the presence of strong genetic control.

Cohorts of instar I larvae of the Douglas-fir tussock moth, Orgyia pseudotsugata, were stocked on branches of white fir, Abies concolor. Branches were either exposed naturally over drop-trays or protected with cages of nylon netting. Only 8.7% of the larvae in exposed cohorts survived to pupate, compared with 68.0% survival in caged cohorts where dispersal and predation were prevented. Losses from the exposed cohorts were caused mostly by arthropod predation, disappearance, and non-replaced dispersal. Disappearance of early larvae was attributed primarily to predation by spiders and insects while disappearance of late larvae was suspected to be due mostly to bird predation. In an analysis of k-values, actual or suspected predation accounted for 47.2% and dispersal 40.5% of the total loss.

Habitat structure of two collembolan communities, one at Barrow, Alaska, U.S.A., the other at Tuktoyaktuk in the Mackenzie Delta, Canada, has been analyzed in relation to microtopographies characteristic of tundra regions. Multivariate statistical techniques, cluster analyses (UPGMA), and principal component analyses (PCA) reveal various ecological changes in component species. In spite of such local variations in component species, the two communities show similar patterns of habitat structure that are organized principally along a gradient of environmental moisture.

The action of a formamidine pesticide on the ultrastructure of hormone release from the glandular lobe of the corpus cardiacum (CC) of the locust, Locusta migratoria (L.), has been studied. Treatment of the isolated CC with 5 μM desmethylchlordimeform (DCDM) caused depletion of neurosecretory material from the intrinsic cells of the glandular lobe without affecting the nervus corpus cardiacum II axons. Pretreatment of isolated CC with the α-aminergic antagonist (5 μM) phentolamine blocked DCDM-induced release of neurosecretory material from the glandular cells. DCDM-induced release of neurosecretion from the glandular cell axons occurred via exocytosis. DCDM treatment also affected the distribution of mitochondria. Mitochondria from adjacent cells lined up along the plasma membrane, forming pairs in juxtaposition.

Two blocks (one .36, other .48 ha) of filbert (hazelnut), Corylus avellana L., trees were left unsprayed for 10 years and the pest status of different species determined by periodic field examination and damage counts. The omission of all pesticides resulted in excessive build-up of the filbertworm, Melissopus latiferreanus (Wals.) (Lepidoptera: Olethreutidae) populations resulting in an average of over 20% nut damage. Filbert leafroller, Archips rosanus (L.) (Lepidoptera: Tortricidae), and filbert aphid, Myzocallis coryli (Goeze) (Hemiptera: Aphididae), populations declined and no apparent economic damage was caused by these two pests. No damage was observed from other recorded arthropod pests.

An economic analysis of standard filbert pest control programs in the Willamette Valley of Oregon indicated that during the study years, the total insecticide spray expenditures in commercial orchards ranged from 6.5% to 18.3% of the yearly returns in U.S. dollars/ha. Damage in unsprayed study orchards during this 10-year period suggests that the sprays applied for the control of aphid and leafroller yielded no return, while the sprays applied for control of the filbertworm returned an average of $3.80 for every dollar spent.

Field tests were used to evaluate the efficacy of liquid acephate in aerial applications to control grasshoppers on rangeland. An antidrift additive applied with the treatment was also evaluated. A rate of 105 g AI/ha of acephate at volumes of 2337, 1899, and 1461 mL of mix/ha with the addition of Nalco-trol® resulted in control statistically as good as the standard malathion treatment of 653 g AI/ha. Two formulations of acephate applied at the rate of 105 g AI/ha in a volume of 2337 mL/ha were compared and resulted in statistically comparable mortalities; both formulations of acephate resulted in excellent control 10 days after treatment.

The bionomics of the red pine shoot moth, Dioryctria resinosella Mutuura, a newly described species of shoot borer in red pine, Pinus resinosa Ait., were investigated in Wisconsin sand plains plantations. The appearance of eggs, larvae, pupae, and adults are described. Head-capsule measurements indicated five larval instars. First-instar larvae overwintered in hibernacula. Shoot feeding was generally initiated by third-instar larvae in late May. Cones also were attacked. Pupation occurred in July. The flight period extended from mid-July to mid-September. The sex ratio was 0.53. Only red pine shoots and cones were attacked in a mixed pine stand. Infestation rates were highest along plantation edges, in the top half of the crown and in plantations greater than 20 years of age. Hyssopus rhyacioniae Gahan occurred most frequently among parasitoids reared from larvae and pupae.

Adults of Uchidastygacarus (s.s.) acadiensis n. sp. are described from specimens collected from gravel and sand bars in streams in the Atlantic Provinces of Canada. Comments on the distribution of mites of the genus are presented.

A simple empirical model of temperature variation with elevation was successfully used to explain variation in observed rates of development of larvae and pupae of the western spruce budworm in mountainous terrain. Hopkins' Bioclimatic Law did not adequately describe development of stages earlier than the sixth instar. Regional differences in the effect of elevation are demonstrated and related to coastal and interior conditions. Direct solar heating effects appear to be of major significance in the early instars. The empirically-derived rates of temperature decrease could be generally applied to regions with dry inland conditions, but not to moist coastal regions.

Laboratory tests were conducted under simulated stream conditions to determine the efficacies of microencapsulated formulations of chlorpyrifos-methyl (Reldan® 10–10) against Simulium and Prosimulium late-instar larvae. In tests with eight formulations, no correlation was evident between efficacy and formulation stability (i.e., cross-linking ratio). The most effective formulations were 34-75-50A, 119-75-6A, and 119-75-6C. The LC50 and LC90 values of 34–75–50A against S. vittatum were 5.5 μg/L and 24 μg/L/10 min. respectively. The formulations 119-75-6A and 119-75-6C were statistically not different from 34-75-50A. Prosimulium magnum was less susceptible (LC50 = 36μg/L, LC90 = 205 μg/L). Susceptibility among S. vittatum larvae varied inversely with size. Treatment with formulation 34-75-50A at 237 μg/L/10 min (the observed LC100 for S. vittatum) severely affected nymphs of the mayfly Baetis sp. and the stonefly Taeniopteryx burksi, but had a minimal effect on most other detritivores, filter-feeding caddisflies (Hydropsyche betteni and Brachycentrus sp.), and predators. Mortality increased significantly in some of these latter species, however, when exposed to 492 μg/L/10 min (the observed LC100 for P. magnum). Tests indicated that there was some leakage of active ingredient from the microcapsules into the water. Although the microencapsulated formulations of chlorpyrifos-methyl were designed to have selective toxicity to black fly larvae, our laboratory tests indicated that they were not as safe towards nonfilter feeders as had been expected.

Adult emergence of the spotted tentiform leafminer, Phyllonorycter blancardella (F.), and its primary endoparasite, Apanteles ornigis Weed, from overwintering pupae was studied at five constant temperatures. Days to 50% emergence for P. blancardella were 55.4, 24.4, 14.4, 10.8, and 8.3 and for A. ornigis were ∞, 47.8, 25.6, 17.6, and 15.1 at 8°, 12°, 16°, 20°, and 24 °C, respectively. The rate of pupal development was approximately a linear function of temperature for P. blancardella but was nonlinear for A. ornigis. The threshold of development, estimated from the 50% emergence data, was 4.4 ±.33 °C for the host and 9.6 ±.50 °C for the parasite. The development time for the host was approximately one half that for the parasite at temperatures 12°–24 °C. The difference in emergence dates between host and parasite under normal Nova Scotia conditions was predicted to be 35 days. The timing of chemical controls in an integrated pest management program could be predicted from the accumulation of daily development units based on the power function for both species, provided a field study is undertaken to confirm the extrapolation to diurnal temperature regimes.

The two cruciferous plants Thlaspi arvense and Lunaria annua are largely unacceptable to the striped flea beetle, Phyllotreta striolata, which normally feeds on cruciferous plants. Results suggest that these plants contain chemical compounds that act as feeding deterrents to the beetles. Methanol fractions of the leaves of both plants deterred feeding when added to the surface of acceptable radish leaves. An alkaloid fraction of Lunaria annua was, surprisingly, not deterrent. Evidence suggests that saponins in both Lunaria annua and Thlaspi arvense may be a major reason for the low acceptability of these plants as food for Phyllotreta striolata. Commercial saponins are highly deterrent at concentrations of 0.05% and above.

The effectiveness of several commercially available sunlight screens in protecting Bacillus thuringiensis Berliner (B.t.) against inactivation by solar irradiation was assessed in the laboratory and field. Spore viability and residual insecticidal activity of B.t. were rapidly reduced by solar radiation in the range of 300 to 400 nm wavelength. The addition of ultraviolet absorbers, Uvinul DS49 and Erio Acid Red, to a Thuricide spray formulation prolonged the insecticidal residual activity on coniferous trees, resulting in greater effectiveness against the spruce budworm, Choristoneura fumiferana (Clem.), compared with a formulation lacking these protectants.

In the first generation brown mite, Bryobia rubrioculus (Scheuten), on apple inhabits the wood as well as the leaves. To eliminate sampling the wood, which is very tedious and time consuming, equations were developed to describe the total population of immature stages and adults from observations of the number of mites on the leaves alone.