Morphological variation between two closely related species in the genus Amblyseius Berlese was examined by numerical taxonomic methods. Multivariate tests indicated that A. canadensis Chant and Hansell and A. novaescotiae (Chant) represent two separate and distinct morphological groups. This supports their taxonomic retention as valid species. Intraspecific morphological variation was also examined and found to be correlated with climatic and host plant variables.

Data from black fly traps in Deep River over the past 5 years indicate that larvicides applied to breeding sites in streams surrounding the town have substantially reduced the numbers of this pest. Very high numbers occurred in 1972, the result of invasion associated with high westerly and northerly winds at a critical period of time or with heavy protective snow cover during the preceding winter. The lowest population levels occurred in 1975, when treatment included a stream near the town which had not been treated previously. The results indicate that with proper stream management it is possible to substantially reduce the nuisance value of black flies in a small northern town.

Lectotypes are designated for Margaronia curvilinea Janse, 1924, and Margaronia pratti Janse, 1924. These species are referred to Palpita Hübner, [1808], as new combinations. They are redescribed and differentiated from certain closely related species. Phalaena Geometra annulata Fabricius, 1794, and Botys partialis Lederer, 1863, are treated as species inquirenda in the absence of type material. Glyphodes celsalis Walker, 1859, and Margaronia inusitata Butler, 1879, are treated as distinct species and are transferred to Palpita as new combinations. Margaronia warrenalis Swinhoe, 1894, is transferred to Palpita as a new combination; a lectotype is designated for this species and its characters are compared with those of P. curvilinea. Palpita varii n. sp., from Manusela, Ceram, and P. jansei n. sp., from the Island of Mioswar, Geelvink Bay, New Guinea, are described from holotypes drawn from the type-series of P. pratti; characters differentiating these three species are given.

Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), populations were studied on white fir at four areas in central Sierra Nevada mountains of California during 1971–73. Life tables were constructed for four populations in El Dorado County. The number of eggs per egg mass decreased and the percentage eggs parasitized doubled with declining moth populations. Hymenopterous parasitoids were collected from all immature stages of the moth: one egg parasitoid, Telenomus californicus Ashmead, six species of larval parasitoids, principally, Hyposoter sp., and 13 species of larval–pupal parasitoids. Tachinids were predominant and accounted for 73% of the parasitoidism of the cocoons in 1971. The apparent mortality of female pupae due to the parasitoid complex was greater than 97% in 1971 and 75% in 1972. One population in Placer County collapsed in 1971 apparently due to a combination of heat exhaustion and low levels of virus infection. Other defoliators, spiders, and several predatory insect species were collected from the foliage samples simultaneously with the tussock moth during larval sampling. Twelve species of "free living" spiders which could be capable of preying on the defoliator complex of white fir were collected. Parasitoids and predators appear to be potentially important biotic factors at low to moderate host population levels. This is the first recorded case where an agent other than the nucleopolyhedrosis virus has been responsible for the collapse of a Douglas-fir tussock moth population.

The effectiveness of 16 experimental compounds as soil insecticides was assessed under laboratory conditions. Chlorpyrifos, carbofuran, and dieldrin were included as standard insecticides. Spectrum of activity as contact insecticides was determined using 24–48 h nymphs of the field cricket, Acheta pennsylvanicus (Burmeister), 24–48 h onion maggot adults, Hylemya antiqua (Meigen), third stage darksided cutworms, Euxoa messoria (Harris), northern corn rootworm adults, Diabrotica longicornis (Say), and honeybees, Apis mellifera L. First stage crickets were used to assess the biological activity of experimental compounds relative to soil type, moisture, and temperature and also their volatility in moist sand and persistence of biological activity over a 48 week period. All of the insecticides showed broad spectrum contact activity. Twelve showed fair to very good potential in soil. Four insecticides, Shell WL 24794 (O,O-dimethyl-S-1-[3-(5-methyl-1,2,4-oxadiazolyl)] ethyl phosphorodithioate), Shell WL 25735 (O-[2-chloro-1-(2,5-dichlorophenyl) vinyl] O-methyl methylphosphonothioate), Shell WL 26738 (O-[1-(2,4-dichlorophenyl) vinyl] O-methyl ethylphosphonothioate), and chlorpyrifos-methyl showed good potential. Two others, Counter® (S-[(tert-butylthio) methyl] O,O-diethyl phosphorodithioate) and Shell WL 24073 (O-[2-chloro-1-(2,5-dichlorophenyl) vinyl] O-methyl ethylphosphonothioate) were considered to have very good potential as soil insecticides.

Field testing of a large number of synthetic compounds and two-component combinations thereof revealed an attractant for the adult males of Leucania commoides Guenée. Several three-component combinations were tested and the largest numbers of L. commoides males were attracted to Z-9-tetradecen-1-yl acetate, Z-11-hexadecen-1-yl acetate, and Z-11-hexadecen-1-ol in ratios of 4:4:1 to 10:5:2. The attraction of this species was inhibited by Z-9-tetradecen- 1-ol.

The previously unknown biologies of three species of bud mining sawflies occurring in the central Sierra Nevada Mountains are compared. All three species oviposit in the buds of white fir, Abies concolor, but in different parts of the bud. Each has a different ovipositional posture as well. The first instar of each species mines the bud in a characteristic manner; later instar larval behavior is not distinguishable. The larvae cannot be separated morphologically, but the adults are easily recognized by their genitalia. At moderate population levels competition does not appear to be a major limiting factor even though the three species occupy the same niche. The feeding of Pleroneura aldrichi, P. koebelei, and P. lutea appears to have little if any effect on the host tree.

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.

Larvae of Pityokteines elegans Swaine and Scolytus ventralis LeConte are distinguished by differences in coronal suture, frontal suture, antennae, and labium. Anatomical features are illustrated by SEM micrographs.

Four species of Exenterus were reared from the European pine sawfly, Neodiprion sertifer (Geoff.), in Ontario. An introduced species, E. abruptorius (Thunb.), last reported in Ontario in 1948, was recovered in very small numbers at one location. The native E. affinis Roh. (= E. walleyi Cush.) parasitized a small proportion of N. sertifer but was the main species attacking feeding larvae. The native E. nigrifrons (formerly called E. canadensis Prov.) and the introduced E. amictorius (Panz.) occurred at all sampled locations. Both species were more numerous in high than in low density populations of N. sertifer, but E. nigrifrons was more destructive, and E. amictorius less destructive, at high than at low density.

About 60% of adults of E. amictorius and 6% of those of E. nigrifrons eclosed in the same summer that attack occurred. Most were unlikely to have reproduced, owing to the scarcity of hosts. In both species females were more frequent in female than in male hosts.

Samples of N. sertifer cocoons in July were superior to larval samples in June and cocoon samples in August and the following May for measuring the rate of parasitism and the relative abundance of Exenterus spp. However, because of mortality of Exenterus before and after sampling, data based on the rearing of cocoons seriously underestimated the impact of the parasites.

Bacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.

The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.

The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.

Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.

The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

Feeding by aphids during 11 days decreased plant weight between 4.7% at an initial density of 5 aphids/plant and 63.9% when the infestation began with 50 aphids/plant. At this infestation level, plant surface area was decreased by 54.3% after 10 days. Both soluble carbohydrate and total protein were reduced by aphid feeding but caloric equivalent of pea tissue was not significantly affected. Extraction by aphids of up to 3.5 cal/plant day was offset by a compensatory increase in production by the plant. Extraction of about 32.7 cal/plant day, equivalent to 0.46 adult aphids/cm2 of plant surface, completely eliminated pea net primary productivity. The relation between energy extracted by aphids, X, and % reduction of plant NPP, Y = 5.54 X−0.058 X2−19.17. Aphid consumption affected pea production directly by removing the amount actually ingested and indirectly because of lost production that would have resulted from the consumed material. Maximum sustainable efficiency of utilization of pea NPP by aphids was between 41% and 47% and maximum sustainable efficiency of transfer of pea NPP to aphid biomass was between 20% and 23%. These high utilization and transfer efficiencies probably would be reduced under field conditions by factors which limit aphid numbers.

Mixed colonies of adults of Lytta nuttalli Say and L. viridana Le Conte, and of L. cyanipennis (Le Conte) and nuttalli, and colonies containing only one of these three species have been seen in various parts of the Canadian prairies, usually in aggregations and most commonly near bodies of water. The flight period of nuttalli extends from early June to early August, of viridana from late May to late June, and of cyanipennis from mid-June to early July. The natural food plants of these three species are a variety of wild legumes, though they prefer certain cultivated legumes when present. Nuttalli and viridana will eat some non-leguminous plants, including species of Iris, Delphinium, and Brassica, and such crops as sugar beets, oats, barley, and wheat. In captivity, males and females of nuttalli and viridana mated more than once and females deposited more than one batch of eggs. Egg batches of nuttalli, viridana, and cyanipennis contained an average of 320, 340, and 390 eggs each, respectively. Cross-mating between nuttalli and viridana and nuttalli–viridana hybrids were observed in the field. Four nuttalli females were seen ovipositing in an area that contained the remains of nesting cells of leafcutter bees (Megachile sp.); these are the first recorded observations of Lytta species ovipositing in the field. The beetles preferred moist, firm soil for oviposition, and the eggs desiccated very quickly when not in contact with moisture. The eggs of these three species developed fairly uniformly at temperatures from 15° to 30 °C, and it appeared to take about 2 to 3 weeks to complete embryological development at temperatures normally encountered during June through August. Relationships among these three species suggested by their behaviour and biology are discussed.

A laboratory experiment demonstrated that in San Jose scale, Quadraspidiotus perniciosus (Comstock), the male is susceptible to a number of insecticides. Diazinon was the most effective as it killed the males before they emerged from their shells. Males emerged and survived for a short time before being killed by residues of azinphosmethyl and endosulfan. In an orchard, a petal fall spray of diazinon or Penncap E applied when male scales started to emerge gave good control of San Jose scale and was as effective as three summer sprays of diazinon timed to emergence of crawlers. Penncap E was ineffective against the crawlers. Post-bloom sprays are necessary to control infestations of incrusted scale because a pre-bloom oil application usually fails to contact live scale that may be underneath one or more layers of old dead scale.

The European species Perizoma alchemillata (L.), first collected in Newfoundland 22 July 1954, is now widely distributed throughout the island. Notes on its distribution, life-history, and ecology are provided. The adult moths and the male and female genitalia are illustrated to facilitate identification.

Male gypsy moths (Lymantria dispar (L.)) have a superposition compound eye. Electroretinogram (ERG) responses indicate low sensitivity in the ultraviolet region, higher sensitivity from 480 to 590 nm, and essentially no sensitivity in the red region. The microspectrophotometric absorption spectrum of the visual screening pigments shows low absorption in the ultraviolet and red regions and high absorption from 400 to 600 nm. Screening pigments migrate in response to illumination during diurnal activity periods, so the eye acts in the photopic mode. Because these pigments are essentially transparent to ultraviolet wavelengths, the eye may be in effect acting simultaneously in the scotopic mode for these wavelengths.

Manipulation of individual first instar larvae of the oriental fruit moth (OFM) has been successful using a sable hair (Fisher and Menzies 1976). However, when large numbers of larvae must be treated quickly and held for a long time, they cannot be handled singly. Also, larvae exposed to insecticides, even for short periods, are hard to retain on a substratum for observation.

Ooencyrtus leptoglossi n. sp. is described and illustrated. This species is a parasite of the coreid bug (attacking pine seed) in Georgia, U.S.A.

Frontalin, a synthetic pheromone, induces attacks by the spruce beetle (Dendroctonus rufipennis) on baited standing trees, in which most broods fail. The impact of baiting 100 randomly chosen trees was determined by estimating the beetle population in a 766-ha spruce forest. Attack density in infested bark was similar for wind-thrown and baited trees; however, 95% of attacks occurred on the former, which were more numerous and had greater attacked surface areas. In this forest, it is estimated that 34 frontalin-baited trees would have been required for each windfall to trap 90% of the beetle population.

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.