The relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

Residue analysis of apple foliage obtained from an orchard treated with the insecticides cypermethrin, fenvalerate, deltamethrin, permethrin, and azinphos-methyl revealed detectable residues on the leaves 8–9 weeks after the last treatment. Laboratory studies of foliage showed that of the synthetic pyrethroids, permethrin was initially as toxic as the other synthetic pyrethroids; however, its toxicity decreased considerably by the 5th and 6th week post-treatment. Azinphos-methyl was the least persistent and toxic insecticide evaluated. Unless new pest-management strategies are developed, the use of synthetic pyrethroids post-bloom in an integrated-pest-management program would not be desirable where Amblyseius fallacis (Garman) is the principal predator of phytophagous mites.

Searching for adult coccinellids in large cages placed over sections of strawberry fields produced an average of 10 times as many coccinellids per metre of row as a relative method of sampling. Methods of converting relative indices to absolute indices of abundance were found. Results suggest that the frequently observed slow increase in abundance of aphid predators in response to increasing aphid abundance may be an artifact resulting from using relative indices of abundance that make no correction for the effects of hunger on predator activity. Calibrating the samples shows that numbers of adult coccinellids follow the trend of aphid abundance closely enough that coccinellid numbers may be predictable.

Two species of opiine (Braconidae) parasitoids, Opius lectoides Gahan and O. downesi Gahan parasitized Rhagoletis zephyria Snow and R. pomonella (Walsh) in the Willamette Valley, OR. Almost equal numbers of O. lectoides and O. downesi were recorded from R. zephyria, whereas about 91% of the opiines associated with R. pomonella were O. downesi. In general, percent parasitization of R. pomonella was variable from sample to sample, but substantially higher on hawthorn than on apple fruit. It appears that both the opiine species have made a rapid host shift from R. zephyria to newly introduced populations of R. pomonella.

Early removal of the alfalfa canopy not only reduced the population density of Agromyza frontella (Rond.) by the elimination of partially developed larvae, but also by increasing mortality of individuals that had already evacuated their mines. This mortality was associated with increased temperatures and/or decreased humidity of the soil, as most pupae are found close to the surface due to the limited burrowing capacity of prepupae. Harvesting data should be included in predictive models, as this parameter affects both the number and time of adult emergence.

Sampling statistics for adult northern corn rootworms in New York field corn are reported, with particular reference to efficient monitoring for decision-making in pest management. The most efficient sample unit of those examined was a single, entire plant. Sample sizes and associated costs required to achieve fixed levels of precision for estimates of density are reported. Because required sample sizes are density dependent, a sequential-sampling plan providing final estimates of density at preset levels of precision is developed. The method makes no assumption about the frequency distribution of insect counts, which was found to vary from field to field and with time. Disturbance caused by sampling activity may introduce a bias of unknown direction and magnitude in estimates of beetle density. Care in approaching and examining plants; should reduce this bias.

The development and survival of mountain pine beetles axenically reared on standardized diet at 8 constant temperatures (10°–35 °C) were observed. At 32 °and 35 °C, 22 and 18% of the eggs hatched and all larvae died within 10 d of hatching. At the lower temperatures, 60–70% of the eggs hatched. The highest survival for all developmental stages was at 24 °C. At 10° and 15 °C development of all beetles reared in bolts of lodgepole pine or on axenic diet stopped when larvae were fully developed, whereas at 24 °and 27 °C all of the beetles developed normally to the adult stage. Larvae that had stopped developing during rearing at 15 °C resumed development after being transferred to 24 °C, indicating that pupation was limited by temperature. Although mean development times to the larval, pupal, and adult stages all decreased with increasing incubation temperature, heat-unit requirements above a base temperature of 5.6 °C were lowest for individuals reared at 27 °and 24 °C for all developmental stages. At these temperatures, an estimated average of 673 and 674 degree-days above 5.6 °C were required for development from egg to the tanned (dark) adult stage, respectively. The average widths of the prothorax and the sex ratios of axenic beetles were within published ranges. Mean development times and heat-unit requirements at constant temperatures for development to various life stages agreed well with published field and laboratory studies from western Canada.

Coincident populations of spruce budworm, Choristoneura fumiferana (Clem.) and spruce coneworm, Dioryctria reniculelloides (Mutuura and Munroe) were studied to compare spatial distribution, temporal abundance, relative abundance on spruce species, and the relative efficacy of aerial insecticide treatments.Most individuals of both species were found overwintering on the mid-crown branches of red spruce, and a whole branch is a suitable unit for simultaneous sampling of overwintering budworm/coneworm populations on red spruce. Survey records since 1949 show similar geographical and temporal population trends for these 2 insects in Maine. A correlation analysis (r = 0.87) indicates that the size of their coincident populations is related spatially. Both species were found overwintering in nearly equal proportions on red and white spruce sampled from the same stands. But twice as many budworm and coneworm were found overwintering on red spruce when red and black spruce were sampled on the same stands. Due to behavioral or physiological traits the coneworm appeared resistant to aerial spray treatments that significantly reduced budworm populations.

The egg and larval instars of Pachybrachis peccans Suffrian and P. bivittatus Say are described and illustrated. Adults of both species appear in late May, feed on willow leaves, mate and oviposit in June–July. The larvae, unable to climb the host plants, feed in the leaf litter of dead leaves of willow; they reach the second-last or last instar by the end of the fall; then they seal their case and overwinter. Pupation occurs the following spring, probably in early May.

Larval instars can be distinguished as follows: first instar with egg bursters on meso- and metathorax, with typical head chaetotaxy consisting of flattened-papillate setae and 1 pair of very long simple setae, and tibiae with 2 pairs of spiniform setae; older instars without egg bursters, and showing differences in size, in head and pronotal chaetotaxy, and in the number of spiniform setae on the tibiae.

In the larvae, the premental sclerites of the head seem to be present throughout the Campsomata, a group with case-bearing larvae and not only in the Lamprosomatinae as previously reported.

A new subspecies, Ornithoptera (Schoenbergia) tithonus misoolana from Mysol Island, Indonesia is described, from the ♀, only.

Shivaphis catalpinari sp. nov. from Celtis australis L. is described. The taxonomic position of this aphid with respect to the other species of the genus is discussed.

Functional wing length (wing length/head-capsule width) of female Sweltsa revelstoka (Jewett) from streams was measured for 19 sites that have been free of Wisconsin glacial ice for about 15 000 years and possibly longer, and from 23 sites that have been ice free for about 10 000 years. At the former sites brachypterous populations were common and there was a significant negative relationship between functional wing length and elevation, and a positive relationship between functional wing length and stream size. In the area that deglaciated more recently, populations were not or only slightly brachypterous and there was no significant relationship between wing length and elevation or between wing length and stream size. Functional wing length was not related to body size. These analyses indicate that the brachypterous condition is probably genotypic in origin. I suggest that streams were colonized by macropterous forms shortly after deglaciation, and that brachyptery takes several millennia to develop at small, high-elevation streams.

A hood incorporating a removable air filter and an electrostatic dust precipitator reduced the numbers of air-borne scales around laboratory workers handling insects, thereby reducing the occupational hazard of allergic reactions. The hood is mobile and easy to maintain. Construction details are provided.

The fundatrix morph of Longicaudus trirhodus (Walker) is described for the first time. The main difference from the apterous viviparous female is the absence of cornicles. Fundatrices as well as both apterous and alate viviparous female were collected on cultivated roses in May and early June, 1984 at Fredericton, NB.

The influence of potato cultivar (Solanum tuberosum tuberosum (L.) cvs. Katahdin (long-season), Norchip (mid-season), and Superior (short-season)) and vertical leaf position on certain life statistics of the green peach aphid, Myzus persicae (Sulzer), were assessed in a glasshouse environment. Aphids were caged on upper and lower leaves of each cultivar. Developmental time requirements for pre-reproductive life stages were similar among cultivars and between leaf positions. Longevity was similar among cultivars within leaf position. However, aphids survived 62.3, 53.6, and longer on lower leaves than on upper leaves of Superior, Norchip, and Katahdin (p < 0.05 on Superior and Katahdin). Mean generation time (MGT) was similar among cultivars on upper leaves. On lower leaves, MGT was shorter on Superior than on Katahdin. MGT was 15.2, 6.9, and shorter on lower leaves than on upper leaves of Superior, Norchip, and Katahdin, respectively (p < 0.05 on Superior). Total fecundity and intrinsic rate of increase were greater on the lower leaves of each cultivar.

In a previous report (Jansson and Smilowitz 1985), several life statistics of Myzus persicae (Sulzer) were compared on upper and lower leaves of three potato cultivars (Solanum tuberosum tuberosum cvs. Katahdin, Norchip, and Superior). In general, life statistics were similar (p > 0.05) between cultivars. However, certain life statistics (fecundity and intrinsic rate of increase) consistently were greater (p < 0.05) on lower leaves than on upper leaves of each cultivar. In the previous study, we did not include data on age-specific survival or the relationship between fecundity and longevity to support the premise that the population dynamics of M. persicae on potato are related to the physiological age of leaves (i.e. nutritional quality of leaves) (see Jansson and Smilowitz 1985). This information would be useful for developing a model describing the population dynamics of M. persicae. For this reason, we present here data on age-specific survival and the relationship between fecundity and longevity of M. persicae on upper and lower leaves of three Dotato cultivars.

The face fly, Musca autumnalis De Geer, overwinters in an imaginal diapause characterized by cessation of reproductive activity and hypertrophy of the fat body (Stoffolano and Matthysse 1967). As in species of mosquitoes that employ a similar overwintering strategy (see Washino 1977), the potential of the face fly to serve as a vector of animal disease agents would be enhanced if flies contact animals prior to hibernation, thus possibly acquiring pathogens that overwinter in the insects. Because little is known about the prehibernation behavior of the face fly, a vector of several parasites of cattle (Branch and Stoffolano 1974; Bech-Neilsen et al. 1982), we here report observations of the physiological condition of face flies captured from cattle during the fall months.

Disruption of mating and of trap capture of spruce budworm, Choristoneura fumiferana (Clem.), has been accomplished in recent years (reviewed in Silk and Kuenen 1984) by disseminating large quantities of the primary components (synthetic) of the female sex pheromone within a forest environment. These components (E)- and (2)-11-tetradecenal (E/Z11-14:Ald) (Sanders and Weatherston 1976) are emitted by virgin female budworm at a 95/5 E/Z ratio (Silk et al. 1980). Unsaturated aldehydes are expensive, tend to polymerize readily (Dunkelblum et al. 1984), and are susceptible to air oxidation and/or photodegradation in the field environment. Analogues, with increased stability and reduced cost, that duplicate the effects of these pheromone components would therefore be of practical value.

The spruce coneworm, Dioryctria reniculleloides (Mut. and Mun.), is often associated with the spruce budworm on spruce host trees and sometimes approaches or equals the spruce budworm, Choristoneura fumiferana (Clem.), in numbers (Spies and Dimond 1985). The coneworn is probably~responsiblefo r some of the damage on spruce attributed to the budworm, and with much balsam fir in eastern North America now dead from defoliation or harvested, there is increasing interest in spruce as the major resource to protect.

In a series of papers (Vickery and Nagy 1973; Vickery et al. 1974; Vickery and Kevan 1983), 2 members of the genus Trimerotropis were considered to be subspecies, T. verrruculata verruculata (Kirby) and T. verruculata suffusa Scudder. This relationship was based in part on a statement by Hebard (1929) that 1 was sometimes mistaken for the other where the ranges meet. The former is widespread across the northern part of the continent from Newfoundland to British Columbia and north into the Northwest Territories. The latter is a western taxon, occurring from British Columbia southward into California. Helwig (1955) reported on genetic studies of hybrids between the 2. We made no careful study of the problem, but accepted that production of hybrids indicated a lack of reproductive isolation and therefore considered them as subspecies even though the work of Helwig (1955) indicated that the F, hybrids may be infertile.