Vol. 114, 1982

p. 1102, Table I, column 1, 2nd last entry, forZ7-12:OH + E9-14:Ac read Z7-12:OH + Z9-14:Ac

Simulated windrow experiments revealed that 32.0 ± 8.4% or 3rd-instar Agromyza frontella (Rondani) larvae completed development and formed puparia in alfalfa hay during field curing; 1st- and 2nd-instar larvae suffered almost complete mortality. Under a management schedule where first harvest was at 10% bloom, adult emergence was 45% higher from soil under windrowed hay than from soil under strips immediately raked. Development of A. frontella in hay being field-cured is discussed in relation to crop pest management and crop management options.

The persistence of Neodiprion sertifer nuclear polyhedrosis virus (NPV) on Pinus contorta foliage samples collected from sawfly infested plantations located throughout Britain was studied. Sawfly density and disease epizootiology varied between localities. Results from the bioassay of branch samples, divided into bark, needle base and foliage samples, indicated that N. sertifer NPV produced during a single virus epizootic can persist for at least 2 years on the pine foliage. Bark and needle base samples were found to be contaminated with NPV more often than foliage samples, perhaps reflecting the effect of weathering on the persistence of virus on the needle surface.

A 3-year faunal survey of insecticide-free potato fields revealed that Carabidae were the most abundant ground arthropods followed by Arachnida and Staphylinidae. Generic and species composition of Carabidae did not vary substantially from year to year but abundance did. The arthropods were distributed along a gradient decreasing with distance from the edge of the field closest to the woodland. Results of yellow pan trappings indicated that all types of Carabidae present in the pitfalls could fly but that flight activity was variable among genera. More than 50% of Staphylinidae and 85% of the Carabidae were trapped in the yellow pans at the time of field colonization in June. The significance of these findings in relation to the potential of the arthropods for natural biological control of potato pests is discussed.

Public participation in home vegetable gardening and small farm operations is increasing in North America. This is expected to intensify the use of insecticides and disproportionately increase public exposure to them. For instance, von Rurnker et al. (1972) estimated that on an area basis homeowners in the midwestern United States applied ca. 5.0 lb of pesticides per acre. This amount when compared with 1½ to 3 lb per acre applied by the farmer suggests that backyard gardens receive a heavier pesticide application than most other land areas in the United States. It is, therefore, important to develop ecologically less aggressive control methods for small farm operations.

Females of Glypta fumiferanae (Viereck) (Hymenoptera: Ichneumonidae) lived 8–28 days and oviposited 42–176 eggs if fed honey but lived only 2–5 days and oviposited 4–89 eggs if unfed. Experiments were done under near natural conditions of temperature and humidity (15°–26 °C and 50–80% R.H.). At low host densities fed adults oviposited live eggs daily and unfed adults, 10. Starved adults at low host densities lived about a day longer than those at high host densities indicating that resorption of eggs may occur in this species. General parasite and host density relationships are discussed.

Placing preserved animals in the wide arm of a fluid-filled U-shaped open tube provides an accurate linear measure of biomass. Changes in fluid level are monitored by projecting an image of the tube into a dissecting microscope equipped with an ocular micrometer. Precision of the calibration curves is equivalent to length–weight regressions. However, only a single curve need be generated to predict wet weight of many taxa. Separate calibration curves are required to predict dry weights of hard- and soft-bodied taxa. The instrument is not suitable for measuring biomass of living individuals.

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.

This note deals with four reddish species of European Psallus Fieber known to occur in Canada. Psallus roseus Fabricius was discovered in 1970 in British Columbia, and P. lepidus Fieber and P. jlavellus Stichel were discovered in 1976 in Nova Scotia and are now reported for the first time from the Nearctic region. They were probably introduced accidentally into this country some time ago with nursery stock. The fourth species, P. falleni Reuter, misidentified in North America as P. alnicola Douglas & Scott, is probably naturally Holarctic in distribution. The four species are redescribed, vesicae, left claspers and two adults are illustrated, and a key to separate them is provided.

Lytta nuttalli Say, a large purple and green blister beetle, readily attacks rapeseed in western Canada (Church 1975; Church and Gerber 1976, 1977). As L. nuttalli commonly feeds on caragana (Caragana arborescens Lam.) on the Canadian prairies, attacks on rapeseed crops often occur near caragana hedges. A typical attack was observed near Vanscoy, Saskatchewan in July 1981. A large number of L. nuttalli, from an adjacent caragana hedge where they were abundant, were feeding on experimental plots of a canola variety of Brassica napus L. rapeseed, and rapidly devouring leaves, stems, and flowering heads. Often they chewed off the stems and fed on the severed plant parts on the ground. There were such large clusters of the beetles on some plants that stems were bent to the ground. The gregarious behaviour of these beetles, and their habit of assembling in clusters on their food plants, are well known (Selander 1960; Church 1975; Church and Gerber 1976, 1977). In the experimental plots at Vanscoy, insecticide application was necessary for survival of the canola plants. Fortunately, attacks by L. nuttalli on commercial canola crops are not frequent enough to constitute a major problem. Increased canola production itself is not likely to cause major increases in L. nuttalli populations, as populations are probably limited by the availability of ground-nesting leafcutter bee cells, which are necessary for larval development (Church 1975; Church and Gerber 1976).

Experiments were conducted on Fraser fir, Abies fraseri (Pursh) Poir, seedlings or cut terminals. Results indicate that Oligonychus ununguis (Jacobi) responds most favorably to temperatures approximating 26 °C and to relative humidity levels approaching 50 to 60%. Developmental time, time to 50% mortality, net reproductive rate, mean generation time, intrinsic rate of natural increase, finite rate of increase, and days for populations to double were computed for each temperature and relative humidity regime. Simulated rainfall severely limits population density on Fraser fir seedlings.

Observed and expected frequencies with which fir engraver (Scolytus ventralis) attacks contacted resin blisters or canals in the cortex of white fir (Abies concolor) stems were compared. Cortical regions of the stems were sampled by single bolts sawn from each of 24 firs which had been attacked after felling. Expected frequencies were based on mean proportions of bole surface occupied by the resin structures at attack sites on the bolt. Frequencies were compared on a per-bolt basis and results were combined for χ2 tests. Blister contact (6.5% of attacks sampled) was less than expected (14.0%). Canal contact (17.4%) exceeded the expected (8.2%). Contact frequencies varied directly with percentages of bole surface occupied by the resin structures, and the latter varied significantly among sample bolts. Among-bolt variations in the resin structures were not related to diameters, radial growth rates, or ages of the sections of stem included in the bolts, except that bolts with greater diameters and radial growth rates tended to have lower percentages of bole surface occupied by canals. Almost all beetle attacks that contacted the resin structures failed to produce larval galleries. Results indicate that unless firs are more heavily blistered or canalled than those sampled, the cortical resin system alone is apparently inadequate to protect the trees against the beetles.

Flower production, fruit set, and pollinator activity were measured in two 1-year postburn blueberry fields on the coastal barrens of the Avalon Peninsula, Newfoundland. Honey bees were stocked at a density of 1.7 colonies/ha in one field while the control field lacked honey bees. Bloom production was similar in the two fields but fruit set was 54% in the test compared with 39% in the control field. Native pollinator (bee) populations were similar between fields but total pollinator populations were much higher in the test field with the difference contributed by honey bees. On the coastal barrens, where native pollinator populations are low and bloom exists in abundance for a short period of time, under-pollination may limit fruit set under some conditions and thus honey bees may have value in increasing fruit yield.

Larval biomass of the spruce bud worm, Choristoneura fumiferana (Clem.), in balsam fir, Abies balsamea L., stands was significantly reduced following aerial applications of commercial Bacillus thuringiensis (B.t.) (Thuricide 16B®, 24B and 32BX and Dipel 85®). Treatment with Dipel vehicle (Dipel 88® without B.t.) did not affect larval biomass. Biomass reduction following the Thuricide treatment was directly related to feeding activity. These findings support published observations on the long-term effect of B.t. on budworm populations.

Described are adults of Atylotus insuetus (Osten Sacken), A. calcar n. sp., A. utahensis (Rowe and Knowlton) and A. tingaureus (Philip) and immature stages of the first two species. The distribution of the four species in western North America is plotted and a key is provided for their separation.

Several species of Lygus (Hahn) that occur in Saskatchewan are serious and continuing pests of alfalfa grown for seed. They are readily controlled by any one of several insecticides, but the efficiency of this control is dependent upon knowing their seasonal development and occurrence on the crop.

In the years 1976 and 1978, at three locations in Saskatchewan, populations of Lygus in alfalfa seed crops were sampled at 5- to 7-day intervals throughout the period of insect activity. In 1979 and 1980 samples of bugs were taken occasionally from the same locations, and in all years from other locations in the province. A sample consisted of 0–700 specimens collected by either a 38-cm sweepnet in not less than 25 and as many as 200 random sweeps, or a D-Vac sampler in not less than 3 m2 in spring and after harvest when sweep-sampling was not possible. Collected specimens were preserved in alcohol, sorted, and identified. Additional data, not previously published, were available from a similar mid-1950's study of Lygus seasonal occurrence in alfalfa seed crops in the Torch River district of northeastern Saskatchewan.

The effect of interplanting collards with a mixture of herbs on oviposition of the imported cabbageworm, Pieris rapae (L.), was investigated at Chesterfield Co., Virginia during 1981 and 1982. Analysis of the dispersion indices of the insect using Taylor's power law and Iwao's model revealed that P. rapae eggs were significantly — m (P < 0.001) clumped (b > 1) on collards interplanted with herbs. However, insect counts on control collards conformed to the Poisson distribution (b = 1, P > 0.05). Pieris rapae laid significantly (P < 0.01) more eggs on collards hidden between sage than on collards hidden between other companion plants. Also, P. rapae laid significantly (P < 0.005) more eggs on collards bordered by companion plants than on non-bordered control. These data suggest that companion herbs did not repel P. rapae but instead significantly encouraged colonization of the insect and produced an aggregated distribution.

Using the pea aphid, Acyrthosiphon pisum (Harris), as the host and Aphidius smithi Sharma and Subba Rao as the primary parasitoid, intraspecific tertiary parasitoidism was studied in the aphid hyperparasitoid, Asaphes lucens (Provancher). Laboratory experiments indicated that tertiary parasitoidism by a second A. lucens female on a first A. lucens is possible. Although the average success rate over 18 test-days was 16.9%, however, the day of attack by the second A. lucens female in reference to the age of the first A. lucens larva or pupa developing inside the dead aphid "mummy" was of major importance. Success by the second A. lucens in the early days averaged 27.2%, but was significantly reduced to an average of only 1% for the last 7 days. Comparisons are made with similar experiments on intraspecific tertiary parasitoidism using another aphid hyperparasitoid, Dendrocerus carpenteri (Curtis).

This note deals with European Orthotylini species Pseudoloxops coccineus (Meyer) now known to occur in Canada. It was first discovered in Ontario 20 years ago, and is now reported for the first time. Additional distributional records are given for a European Mirini, Camptozygum aequale (Villers), first reported from the Nearctic region by Wheeler and Henry (1973). The two species were probably introduced accidentally into this country with nursery stock importations of Fraxinus excelsior and Pinus sylvestris, respectively.

Rhinocyllus conicus Froelich was introduced from Europe into Canada and the United States for the biological control of Carduus thistles (Kok 1981). Although several reports indicate that the larval and pupal stages of R. conicus are parasitized by native hymenopterous parasites (Dowd and Kok 1982; Puttler et al. 1978; Rees 1977; Surles 1974) and by mites (Goeden and Ricker 1977) in the USA, no native parasite attacking eggs or adults of R. conicus has ever been reported. However, in 1981 and 1982, flies emerged from puparia formed beside field collected adult R. conicus which were maintained in the laboratory. Three specimens were obtained and identified as Hyalomyodes triangulifer (Loew) (Diptera: Tachinidae). This is the first native nearctic parasite known to attack adult R. conicus.