Studies in eastern Ontario showed that the exotic parasite Dacnusa dryas (Nixon) typically has three generations a year that correspond seasonally to those of its host, the alfalfa blotch leafminer, Agromyza frontella (Rondani). The mature larvae of the third generation enter diapause in September and resume development in the spring. The egg – first instar interval, which occurs within the actively feeding leafminer, developed at rates similar to those of the host larva. The remaining two instars and the pupa, which occur within the host puparium, developed at rates similar to those of the host pupa; in the two non-diapausing generations, the durations of these stages decreased with rise in temperature from 13 to 23 °C. Coincidence of wasp flight and hatch of leafminer eggs was high in all three generations. This host–parasite synchrony results mainly from a sequence of three events during their life cycles: lack of development of the parasite beyond the first instar within the host larva, a temperature-dependent rate of development of the subsequent stages which is similar to that of the host pupa, and different overwintering strategies which result in the parasite emerging later than its host to sustain the relationship. Behavior of the parasite is described in relation to host detection, egg deposition, and reproduction.

Cicindela hirticollis Say 1817 is associated with shoreline and riverine sand deposits and is widely distributed in North America. Geographic variation in this species was analyzed by multivariate analysis of size, elytral markings, and color data obtained from some 4000 specimens from 75 sites throughout the species distribution. Eleven subspecies are recognized and discussed: C.h. hirticollis Say, gravida LeC., ponderosa Thorns., abrupta Csy., rhodensis Calder, corpuscula Rumpp, shelfordi, athabascensis, coloradula, couleensis, and siuslawensis Graves. Possible Pleistocene réfugia, and redistribution of the species following continental glaciation are discussed. Theoretical advantages of certain variants in particular climates or on certain substrates, are considered. Cicindela hirticollis has been eliminated or is endangered in many of its former habitats due to human activities.

Five new subspecies are described: C. h. shelfordi (type locality: Guthrie, OK) which inhabits the Great Plains region; C. h. athabascensis from the Lake Athabasca Sand Dunes of Saskatchewan and Alberta; C. h. coloradula from the Little Colorado River, AZ; C. h. couleensis (type locality: Vantage, WA) which is distributed in the Columbia–Snake river system of Washington, Oregon, and Idaho; and C. h. siuslawensis (type locality: Florence, OR) which inhabits the Pacific coast of Oregon and Washington.

Sixteen hymenopteran and one dipteran species of parasites were recovered from Rhyacionia zozana (Kearfott) larvae and pupae collected in California and Oregon. Total percentage parasitism was high, averaging 47.2% in quantitative studies. The ichneumonid wasp, Glypta zozanae Walley and Barron, was the most abundant parasite, attacking over 30% of the hosts collected. Parasitization rates were presented for each parasite species recovered. Two suspected predators, Phyllobaenus binotatus (Chapin) (Coleoptera: Cleridae) and Leptothorax sp. (Hymenoptera: Formicidae), were found in association with R. zozana cocoons. A single Aegilips sp. (Hymenoptera: Figitidae) was recovered from a host cocoon; the relation between this parasite and R. zozana is as yet undetermined. Parasite biologies were discussed.

Three benzoylphenylurea insecticides, diflubenzuron, triflumuron, and teflubenzuron, were toxic when applied to eggs of Phyllonorycter blancardella (Fabr.) 0–2 and 4–6 days post-oviposition. Most treated eggs hatched but larvae died in the early instars. High larval mortalities also occurred when treatments were applied to foliage prior to oviposition. Treatments applied to larvae, especially older larvae, were less toxic than those applied to eggs. In the field, control was similar whether insecticides were applied during egg deposition, first hatch of eggs, or against early-instar larvae. Applications during egg deposition are suggested as optimal for control. Control of spotted tentiform leafminer with insect growth regulators was equivalent to that obtained with deltamethrin or methomyl.

Residues of diflubenzuron and triflumuron, applied pre-bloom, persisted until leaf drop 19 weeks later. Residues of teflubenzuron persisted for 9 weeks. Populations of spotted tentiform leafminer were suppressed throughout the season and residues of all insect growth regulators except teflubenzuron applied in May were toxic to larvae into October.

The efficiency and accuracy of sampling western flower thrips (Frankliniella occidentalis [Pergande]) from “Granny Smith” apple blossom clusters were analyzed during 1986–1987 to develop a sampling plan for research purposes. The accuracy of the “shake” method was compared with an “extraction” process of each of three blossom cluster types: pink, open, and petalless (petal fall). Thrip extractions from combined clusters revealed that a 9-s and 6-s “shake” removed 84 and 74%, of the thrips, respectively, but a 3-s “shake” removed 53%, and was more variable. Open blossom clusters always had higher thrips densities than either pink or petal fall clusters, regardless of the bloom state. The effects of cardinal position within trees were not consistent over time. Clusters from the top of the canopy had more thrips than lower canopy clusters, and apical clusters had more thrips than basal clusters during peak bloom. Variance component analyses indicated that thrips counts from clusters within tree were more variable than counts among trees, even when cluster types were analyzed separately. Two sets of indices (Iwao’s regression of mean crowding on mean density and Taylor’s regression of log variance on log mean density) for each cluster type indicated aggregated spatial patterns. Precision level sampling plans were developed using Iwao’s regression coefficients.

The fecundity and sex ratio of progeny of Muscidifurax zaraptor Kogan and Legner were assessed on <1-day-old to >9-day-old Fannia canicularis (L.) pupae. Two age classes of parasites (1 day old and 2–3 days old) were used. Host age did not significantly affect production of progeny. Mean number of progeny per female increased in both parasite age groups on 3 successive days of host-exposure as the parasites aged: 4.5, 7.4, and 10.4 progeny per female were produced for the 1-day-old parasites and 7.6, 10.4, and 11.8 progeny per female were produced for the 2- to 3-day-old parasites. Sex ratio of progeny was not significantly affected by host age, averaging 77% females (range 63–92%). Mass rearing of F. canicularis on used M. domestica medium is described.

North American species of the Oeneis polixenes (Fabricius, 1775) complex are reviewed. Two new subspecies, Oeneis polixenes luteus and Oeneis polixenes woodi, as well as one new species, Oeneis philipi, are described from northwestern North America. Oeneis polixenes peartiae (Edwards, 1897) is synonymized with Oeneis polixenes subhyalina (Curtis, 1835).

Two new species of aphids are described from Pennsylvania, Uroleucon (Lambersius) stoetzelae sp. nov. from Achillea millefolium L., and Uroleucon (Uroleucon) floricola sp. nov. from Aster sp.

An outbreak of Neodiprion sertifer (Geoffroy) was studied in a lodgepole pine plantation. It was the first tree generation on a 60-ha peatland area. The nuclear polyhedrosis virus (NPV) of N. sertifer was not found in the larval population or in the soil. Within a 1.7-ha experimental plot, a 0.35-ha block was treated with NPV and the ensuing epizootic was studied during three successive summers. The treatment caused 50% mortality of fourth- and fifth-instar larvae. The NPV persisted in the treated block and gradually dispersed into the adjacent blocks. After 2 years, larval mortality was 78% in the treated block and 21% at a distance of 110–125 m from it. The larval population remained at a high level and the outbreak expanded from the experimental plot to the entire 60-ha area in the years following the virus treatment, but few virus-diseased colonies were observed outside the experimental plot. Thus, the capability of this NPV to persist and spread was not sufficient to control and contain the sawfly outbreak.

Grasshopper density and species composition were determined from 1982 to 1985 in four 75-ha pastures in the northern mixed prairie region near Miles City, MT. Treatment in two pastures consisted of sagebrush removal and interseeding alfalfa and cicer milkvetch. Two pastures were not treated. The treated pastures were grazed only half as long as the untreated pastures but with twice the number of steers. Forage yield decreased in all pastures from 1983 to 1985 because of below-average precipitation and grasshopper density increases. In one pasture, 10% of the legume seedlings were destroyed by grasshoppers. The annual rates of increase in total grasshopper presence were similar in treated and untreated pastures. However, Melanoplus sanguinipes (F.), which eats forbs and is a strong flyer, increased more in treated than untreated pastures; six additional abundant species, all of which were grass feeders, did not increase more in treated pastures. Thus, treatments did not markedly affect total grasshopper population trends but did influence species composition and provided additional food plants for some species.

The encyrtid wasp Epidinocarsis lopezi (De Santis) has been introduced into Africa as a biological control agent against the cassava mealybug Phenacoccus manihoti Matile-Ferrero. This host has a defense reaction against the immature parasitoid that involves encapsulation and melanization. Under laboratory conditions, 37.5% of once-stung cassava mealybugs had been parasitized, as indicated by eggs and larvae of the parasitoid in dissected hosts. Of these parasitized cassava mealybugs, 89.6% contained melanized particles (egg, partially melanized larva, internal host tissues, exoskeleton wound scars). Some of the parasitoid larvae were only partially melanized, and either freed themselves from the melanized capsule or else shed it at the next molt. By the 3rd day of their development only 12.5% were completely melanized. In cassava mealybugs with melanized host tissue but no living parasitoid, the survival of the host was not affected by the melanization. The mealybug itself sometimes shed black particles at the next molt and these were found attached to the cast skins. When superparasitized in the laboratory, 68.6% of twice-stung cassava mealybugs contained parasitoids. Mummies collected from a field experiment showed that melanization rates of mummies increased with increasing parasitization rates. Thus, melanization in the cassava mealybug was commonly triggered when E. lopezi oviposited, but this defense reaction was mostly ineffective, permitting the introduced parasitoid to be a successful biological control agent in Africa against the cassava mealybug, a major pest on this important food crop.

The density and efficiency of bumble bees, honey bees, and alfalfa leafcutter bees on sainfoin, Onobrychis viciaefolia Scop., grown in southern Alberta were studied. Six species of bees were identified as pollinators, with alfalfa leafcutter bees comprising 56% of the observations, honey bees 40%, and bumble bees 4%. The density of flowers over the season can be described as curvilinear. The mean number of flowers per raceme decreased significantly over the season. The rate of foraging by pollinator species from flower to flower varied and is described by multiple regression models. Julian date, hour of day, and flower density are the independent variables. More than 90% of the bees visited three or fewer flowers per raceme when 60% of the racemes had three or more flowers available for pollination. The bees foraged on sainfoin for about 12 h per day and average bee density increased significantly with the corresponding flower density. A theoretical approach used to predict the bee populations required to pollinate varying flower densities shows that the required population of bumble bees is about two-thirds that of honey bees or alfalfa leafcutter bees. The observed populations of pollinators did not correspond well with the derived values, probably because multiple visits per flower are required for fertilization.

A list is given for 45 species of drepanosiphine aphids occurring in the Soviet Far East (South Primorye). Descriptions of Iziphya mordvilkoi sp. nov., Subsaltusaphis pulchra sp. nov., S. primoriensis sp. nov., Symydobius minutus sp. nov., and Sinochaitophorus mordvilkoi sp. nov. are presented. A new subgenus Primoriaphis subg. nov. for the species S. pulchra and S. primoriensis is proposed. The taxonomic relationships of the new species are discussed. The following new synonyms are established: Thripsaphis caricis (Mordvilko, 1921) = T. producta Gillette, 1917; Tiliaphis mordvilkoi Pashtshenko, 1984 = T. coreana Quednau, 1979; Tinocallis hemipteleae Zhang and Zhong, 1980 = T. takashihoensis Higuchi, 1972; and Sappocallis Matsumura, 1919 = Tinocallis Matsumura, 1919.

Anaphes iole Girault is redescribed from specimens reared from Lygus hesperus Knight and Pseudatomoscelis seriatus (Reuter). Anaphes anomocerus, A. ovijentatus, and A. perdubius are synonyms of A. iole. Host-induced morphological variation is discussed. The main attributes that vary with host are the relative size of certain funicular articles and their complement of sensory ridges. There is no morphological overlap between populations as indicated by measurements of most other structures. However, certain structural features that can be used to define the species unequivocally were found.

Daily rates of predation by Podisus maculiventris (Say) (Heteroptera: Pentatomidae) on Mexican bean beetle larvae, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), were measured in soybeans, Glycine max (L.). The number of Mexican bean beetle larvae attacked per predator per day remained consistently low throughout 2 years of study. Estimates of the area searched by P. maculiventris were calculated from the number of prey attacked, number of prey available for attack, and leaf area. As leaf area increased, P. maculiventris searched more area, demonstrating a search strategy shared with other predators of canopy-inhabiting prey in soybeans.

Data on the distribution of overwintering jack pine budworm (Choristoneura pinus pinus Free.) collected between 1985 and 1987 in northern Ontario are used to develop guidelines for sampling this stage of the budworm. Two alternative methods of expressing budworm density are considered: counting the number of budworms per metre of branch and counting the number per square metre of branch bark surface area. Estimates of budworm density for three levels in the tree’s crown are given for 4 site-years.

Entire branches are recommended as the sample units as the use of 60-cm branch-tip sections resulted in consistent underestimation of actual density per branch. Jack pine budworm density did not vary among cardinal compass directions and was generally highest at mid-crown levels.

The distributions of two parasitoids, Apanteles fumiferanae Vier. and Glypta fumiferanae (Vier.), which overwinter as an egg or first-instar larva within the jack pine budworm, also were considered. Apanteles was the most abundant parasitoid at all crown levels at all sites examined. Percentage parasitism by Apanteles was highest and that by Glypta was lowest on the branch-tip sections in relation to the branch-basal section, but total percentage parasitism was relatively constant over the entire branch, throughout the tree crown, and from tree to tree. Consequently, the sampling method for jack pine budworm is easily extended for estimating the rate of parasitism and therefore for providing a prediction of mortality that results from these two common parasitoids.

The life history and ultrastructure of the protozoan Malameba locustae (King and Taylor) were studied in the migratory grasshopper Melanoplus sanguinipes (F.) using feeding and injection studies. Insects fed cysts developed infection in the Malpighian tubules 5–6 days later; no trophozoites were observed in haemolymph samples taken 2–20 days post-feeding. After excystment, a few trophozoites entered the midgut epithelium and many were located near the basement membrane of the epithelial cells, where they appeared to degenerate. Trophozoites were not seen to divide in the midgut epithelium, and apparently did not damage this tissue. Trophozoites injected directly into the haemocoel could not be recovered even 4 h after injection, and the Malpighian tubules did not become infected. It was concluded that trophozoites did not penetrate the midgut to enter the haemocoel or move through the haemocoel to infect the Malpighian tubules, but instead probably entered the tubules directly from the gut. Trophozoite ultrastructure in midgut and Malpighian tubules, and cyst wall deposition were described.

The winter moth Operophtera brumata (L.) is a serious introduced pest of apple trees in Nova Scotia. It spread westward through orchards of the Annapolis Valley in the 1950’s and to other deciduous trees throughout Nova Scotia later. The parasites Cyzenis albicans (Fall.) and Agrypon flaveolatum (Grav.) were liberated during 1961 in Nova Scotia and gradually spread throughout the winter moth population. Population dynamics studies were conducted in insecticide-free orchards and corroborated with observations in neglected unsprayed apple trees over a wide area. The winter moth population reached a balanced level in unsprayed orchards at varying densities below the limits of its food supply, but well above an acceptable level for commercial apple production. In young orchards, where trees cover a small percentage of the ground, natural dispersal of larvae appeared to be a suppressing factor. In mature orchards mortality was density dependent during the prepupal to adult stage; mortality was partly due to parasitism and predation but also to other factors.

In a recently completed study involving pheromone trapping of the winter moth, Operophtera brumata (L.), and the Bruce spanworm, O. bruceata (Hulst), on Vancouver Island (Pivnick et al. 1988), I noticed that O. bruceata had wing colouration different from sympatric O. brumata. The west coast O. bruceata has a pale yellow-orange costal margin on the underside of the forewings and this is faint to absent in O. brumata (Fig. 1). It is also absent from O. bruceata in Saskatoon, which is interesting because some authors consider the west coast population of O. bruceata to be a separate species: the western winter moth, O. occidentalis (see Ferguson 1978; Pivnick et al. 1988). Descriptions of O. bruceata (Brown 1962) and O. brumata (Cuming 1961), and a taxonomic key to these two species (Eidt et al. 1966), do not mention any distinctive wing markings that could be used to separate the two species.

Different insecticide spray regimes were tested in 1984, 1985, and 1986 to determine the optimal time to control the Colorado potato beetle, Leptinotarsa decemlineata (Say), on Russet Burbank potatoes in New Brunswick. Insecticides applied in mid-July at the peak of larval abundance when plants were entering into bloom had the greatest efficacy in controlling beetles and protecting the yield. A single insecticide application at 50% bloom was 12–17% and 82–95% more effective than one application at bloom and full growth, respectively.