An investigation of the insects that damage cones (megasporangiate strobili) and seeds of tamarack [Larix laricina (Du Roi) K. Koch] in New Brunswick was undertaken. During two growing seasons (1982 and 1983) cones were removed from natural and planted stands of tamarack on a weekly basis. These cones were dissected, the nature and amount of insect damage recorded, and insect habits documented. Efforts were made to rear to adults any destructive insects encountered in order to identify them and to isolate parasites. Insects destroyed from 24.6 to 88.0% of the seed produced in the stands under study. Larvae of the spruce budworm [Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae)] and the cone maggot [Lasiomma viarium (Huckett) (Diptera: Anthomyiidae)] were responsible for most of the damage. Among insects that caused lesser amounts of damage were a cone midge [Resseliella sp. (Diptera: Cecidomyiidae)], a seed chalcid [Megastigmus sp. (Hymenoptera: Torymidae)], and various lepidopterous larvae. Applications of the insecticides carbofuran and dimethoate reduced the amount of insect damage. Carbofuran applied at the rate of 13.5 g active ingredient per centimetre of diameter at breast height provided the best protection. Trees treated in this manner had 37.0% of their seeds destroyed by insects as opposed to 74.2% on control trees.

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.

Research was conducted on the biology of cereal and grass aphids in the Madison area during 1957-59 in connection with epidemiological investigations of the barley yellow dwarf virus (BYDV). It becomes of increasing importance to know more about these aphids as potential vectors of the virus. Information was needed on the taxonomy, biology and ecology of the vector population to better understand the complex interactions between vector and virus. Two methods were used to obtain data on the occurrence and abundance of aphids. The conventional method of studying aphid populations on host plants was supplemented with intensive research on air-borne aphids, using the yellow-pan water trap developed by Moericke (1951), and the wind trap described by Shands (1942). These traps are shown in Fig. 1. The species of aphids were identified according to keys of Palmer (1952). Names of genera as used in Europe have been indicated in parentheses. In the following report the various forms in the life cycle are referred to as fundatrices (on the winter host), fundatrigenae (produced by fundatrices, the alates of this generation migrate to summer hosts), virginoparae (both apterous and alate individuals on snmmer hosts), and gynoparae (alates migrate from summer hosts to winter hosts).

Tree size and bark surface area infested in trees killed by the western pine beetle (WPB), Dendroctonus brevicomis LeConte, and the density of attacking and emerging WPB were measured on 91 trees spanning five consecutive generations of the insect. The emergence densities of six natural enemies were also estimated.

Trees averaged 50.9 cm in diameter at breast height (DBH) with a mean height to base of infestation (HBI) of 1.1 m. Heights to top of infestation (HTI) averaged 16.0 m, but were significantly lower in trees attacked by the second [70(1)] and third [70(2)] generations, during synthetic pheromone elution, than in the first [69(3)], or fourth [70(3)], and fifth [71(1)] generations, before and after the treatment, respectively. Infested bark area averaged 2005 dm2 per tree for all generations.

WPB attack density declined steadily from 4.36 beetles/dm2 in generation 69(3) to 0.86 beetles/dm2 in 71(1). Sampling errors ranged from 6.67 to 26.27%, higher than the desired 15% in some cases. WPB emergence in field sticky traps (STIK) followed an opposite trend from 1.66 beetles/dm2 in 69(3) to 5.43 beetles/dm2 in 71(1). Sampling errors ranged from 8.39 to 28.26%. WPB emergence in laboratory rearings (REAR) averaged 4.03 beetles/dm2 with no significant differences among the generations. Sampling errors ranged from 8.20 to 28.77%. Because of inconsistent differences between these two methods of measuring WPB emergence, we have reported estimates of both.

Densities of attacking and emerging WPB were found to be uncorrelated with tree diameter, indicating that density was not a function of tree size and that these two variables may be treated as independent random variables when used in product models to estimate area-wide population totals.

Sampling errors for natural enemies were quite large, ranging up to 400%; therefore few conclusions could be drawn. Predators, in descending order of abundance, were Aulonium longum, Medetera aldrichii, Enoclerus lecontei, and Temnochila chlorodia. Parasitoids were less abundant overall than predators, with Roptrocerus xylophagorum more consistently present and at higher average densities than Dinotiscus burkei.

The suppression treatment was applied during the collapse phase of the population cycle and apparently prolonged that phase for two generations. This delay resulted in the death of an additional 120 trees. WPB productivity increased with decreasing density/square decimetre of attacking beetles. Density of attacking beetles appears regulated by exogenous processes acting immediately in an inverse density-dependent manner. The WPB population at Bass Lake would be released from endemic to epidemic status at the equilibrium point reached at a density of attacking adults of loge 1.65 beetles/dm2. Mortality of the developing within-tree life-stages appears regulated by delayed density-dependent processes, but the details of the relationships differ depending upon the assessment method (STIK or REAR) used.

In 1981 and 1982, the following ant species and numbers were detected preying on pupae of the western spruce budworm, Choristoneura occidentalis Freeman, in eastern Oregon and western Montana: Formica obscuripes Forel, 174; Camponotus modoc Wheeler, 160; C. laevigatus Smith, 53; C. vicinus Mayr, 48; F. podzolica Francoeur, 43; F. accreta Francoeur, 32; F. neorufibarbis Emery, 12; F. lasioides Emery, 1; and Formica sp. (microgyna group). The Camponotus species and F. obscuripes were detected preying on budworm on one-third or more of the trees they foraged.

Larvae of both Aedes triseriatus (Say) and Aedes atropalpus (Coquillett) produce oviposition attractants active for A. triseriatus, even when the larvae are pretreated with kaolin. These experiments demonstrate that the earlier observed attractancy of larval holding waters was not simply due to the presence of waste matter or associated microorganisms from the larval gut. It is further shown that the active material may be extracted directly from the larvae into hexane or ether. It is also demonstrated that the larval produced oviposition attractants of these species are similar in their ability to attract gravid females of A. triseriatus.

Resistance to pyrethroid insecticides, identified previously in adults of Phyllonorycter blancardella (Fabr.), was shown to extend to both egg and larval stages. Eggs of both resistant and susceptible strains were more susceptible than larvae to various pyrethroid insecticides. Eggs treated 0–2 days post oviposition were more susceptible than 4- to 6-day-old eggs and/or larvae for both strains. Older larvae, especially from resistant strains, were less susceptible than early instars. For eggs and 1st-instar larvae, differences between resistant and susceptible strains were largely overcome by treatment with higher concentrations of permethrin. In the field, low levels of resistance were overcome by applications of permethrin at 212.5 g AI/ha diluted in 3370 L water/ha timed for first hatch of eggs.

A 3-year study of spatial distribution patterns of insect pests in soybean fields revealed that the Poisson series described the distribution of most species. These species were: green cloverworms, Plathypena scabra (Fabricius); velvetbean caterpillars, Anticarsia gemmatalis Hübner; loopers Trichoplusia ni (Hübner), Pseudoplusia includens (Walker), and Heliothis spp. The Poisson with zeros distribution was second in characterizing the spatial patterns of many of the species. Field counts of Mexican bean beetles, Epilachna varivestis Mulsant, fitted the Neyman’s type A and negative binomial distributions most often.

Phoretic hypopi of the mite genera Anoetus (Anoetidae), Sancassania, Kuzinia and Schwiebea (Acaridae) were commonly found on 11 species of carabids. Deutonymphs of Poecilochirus sp. were also phoretic on the carabids. Other mite genera were present infrequently on the carabids. Mites were found mainly on ventral surfaces of large carabids and rarely under elytra.

The tarnished plant bug, Lygus lineolaris (P. de B.), is the dominant mirid in crops grown in eastern North America (Strong 1968; Bariola 1969). Lygus lineolaris is an ubiquitous species found on a wide range of wild plants and cultivated crops (Knight 1941).

All previously known egg parasitoids of Lygus spp. were mymarids in the genera Anaphes, Erythmelus, and Polynema (CIBC 1979). The mymarid Anaphes iole Girault is the principal egg parasitoid of Lygus spp. in the United States (Debolt 1987). It has been reported from British Columbia, Alberta, Ontario, Quebec, and the Northwest Territories(Huber and Rajakulendran 1988).

Survival and development of Ips paraconfusus Lanier larvae reared individually in intact Pinus ponderosa Laws. phloem without associated fungi and dietary supplements was demonstrated. Survival was reduced.in intact ponderosa pine phloem previously occupied by other larvae or by bluestaining fungi [i.e. Ophiostoma ips (Rumb.) vectored by I. paraconfusus, O. minus (Hedge.) H. & P. Syd. vectored by Dendroctonus brevicomis LeConte, O. clavigerum (Robins.-Jeff. & Davids.) vectored by D. ponderosae Hopkins, and Leptographium terebrantis Barras & Perry vectored by D. valens LeConte] compared with those reared without fungi or symbiotic yeasts. The highest proportion of larvae initiating tunnels and surviving to adult was observed for untreated eggs, and the lowest proportion occurred in the L. terebrantis treatment. Size was reduced and developmental rate was slower for larvae reared without fungi compared with larvae reared with associated fungi.

Tunnels excavated by first- and second-instar larvae reared without associated fungi were longer than those excavated by larvae reared with associated fungi. The most frequent larval turnabouts occurred with larvae reared axenically and reared with Ips yeast and O. ips. The fewest occurred with larvae reared with Ips egg niche plugs and from untreated eggs. Females reared free of any fungi or with Penicillium or Aspergillus did not oviposit in surface-sterilized ponderosa pine logs. Naturally eclosed females from ponderosa pine logs in which they developed, laid eggs in these sterilized logs. Potential for a new association among bark beetles and fungi is discussed.

It has for some time been realized that the genus Pyrausta as it stands in current North American lists is a very unnatural one. Forbes (1926) pointed out that a fundamental division of the Pyraustinae possible on the basis of the presence or absence in the male fore wing of the frenulum hook, and that species of both types have ordinarily been included in Pyrausta. Subsequent studies of genitalic structure—particularly that by Pierce and Metcalfe (1938)—have borne out the importance of this division.

Athrycia cinerea (Coq.) is a univoltine parasite of bertha armyworm, Mamestra configurata Wlk., on rapeseed in the Prairie Provinces of Canada. Details of the parasite’s seasonal life history are presented. Females oviposit on third, fourth, fifth, and sixth instars of bertha armyworm, and the parasite larvae usually develop gregariously and mature on the fifth and sixth instars. Supernumerary parasite larvae on superparasitized hosts starve; surviving larvae develop more rapidly, form smaller pupae with a lower capacity for survival, and eventually produce a consistently though not significantly smaller percentage of female adults than parasites that develop on non-superparasitized hosts. Larvae of A. cinerea are often killed if they compete with larvae of Banchus flavescens Cress., the only other common parasite of bertha armyworm, and a small percentage of the pupae of A. cinerea are killed by a hyperparasitic ichneumonid, Phygadeuon subfuscus Cress.

The greatest predatory effect of small mammals is exerted upon insects that spend a portion of their life cycle on the ground or in the soil. Sawflies afford ample opportunity for mammalian predation, since they drop to the ground as mature larvae and spin cocoons in the soil. Such sawflies as Neodiprion abietis Harr., which remain within the cocoon for about three weeks, undergo only moderate risk of being preyed upon by small mammal. However, Pristiphora erichsonii (Htg.) remains within the cocoon from about mid-August until the following June, or even over more than one year, thus greatly extending the vulnerable period. Earlier investigations suggest that small mammals may comprise the largest single biological control agent acting against this insect (Graham 1928, Lejeune 1951), but the exact role of mammalian predators of forest insects has yet to be established.

The invasive wood-boring beetle Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) poses a serious threat to deciduous trees in North America and Europe, where it has been introduced in solid wood packing material from China (Haack et al. 1997; Krehan 2003). This beetle attacks and ultimately kills a wide variety of hardwood tree species (Nowak et al. 2001; Lingafelter and Hoebeke 2002); it has infested urban shade trees in Canada (Canadian Food Inspection Agency 2004), the United States (Haack 2003), and Austria (Tomiczek 2003) and has damaged poplar (Populus L.; Salicaceae) plantations in its native China (Luo et al. 2003).

Little research has addressed the impacts of invasive-species establishment on native forest insect communities. Such information is lacking even for gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), the most thoroughly studied invasive forest insect. We investigated the ecological impacts of gypsy moth on native species at sites in north-central Ontario, Canada, with and without significant histories of gypsy moth defoliation over a 2-year period. Patterns in native forest caterpillar communities are described using measures of species diversity and multivariate analysis. We documented a transition from low-level to dominant gypsy moth populations. Sites with different gypsy moth outbreak histories exhibited differences in rank-abundance distributions and dominance structures in the first year of the study; by the second year, gypsy moth was dominant at sites of both types irrespective of their previous defoliation history. Contrary to our predictions, we found that gypsy moth outbreak history had no significant effects on native caterpillar community diversity or structure. However, sites with currently high gypsy moth abundance demonstrated significant shifts in late-season caterpillar community structure. Our results suggest that observed community differences were due to the presence of a highly abundant folivore, and not to permanent shifts in the native community because of the introduction of an invasive species.

A 2-year study was conducted in an organic, essentially pesticide-free orchard and in one which followed a complete pesticide program to assess populations of beneficial arthropods. There were far more beneficial species in the pesticide-free orchard both on the trees and in the cover crop. Spiders increased dramatically in the organic orchard and relatively few spiders were found in the sprayed orchard. Pest species were below treatment thresholds in both orchards with the exception of codling moths. By the second season, codling moth injury was so severe in the organic program that the non-pesticide program had to be abandoned.

Tethered gypsy moth larvae, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), placed in various tree microhabitats were most heavily parasitized by Compsilura concinnata (Meigen) (Diptera: Tachinidae) near the ground especially on leaves. In laboratory experiments, hosts were parasitized primarily between 6:00 AM and 6:00 PM (E.S.T.), with little parasitism at night. These data suggest that in the field, this tachinid will most efficiently attack young gypsy moth caterpillars, as instars 1 to 3 are the only ones consistently on or near foliage during daylight. C. concinnata females successfully parasitized young hosts, but larval development on 2nd instars was twice as long as that on 4th instars. Thus, only one generation of parasitoids on gypsy moths is likely per year. Results indicate that methods for improving the effectiveness of this parasitoid should emphasize increasing adult numbers early in the season.

Members of the genus Ips are polygamous. The male excavates the entrance hole and a small nuptial chamber between the inner bark and sapwood. The females then enter and each excavates an egg gallery starting from the nuptial chamber. The number of females per gallery system ranges from 1 to 5 but the most common number is 3. This sex ratio of approximately 3 ♀ ♀: 1 ♂ has been attributed to some mortality factor more lethal to the males in some stage of development. Breeding of isolated pairs under laboratory conditions was carried out primarily to determine the variability between individuals from the same brood and between individuals from different broods. The objective was to resolve the complex of closely related species in the Ips tridens–I. engelmanni group. An unexpected result was a clarification of the sex ratio problem.

A dark green aphid was isolated from a greenhouse colony of green peach aphid, Myzus persicae (Sulzer), in Fredericton, N.B. The green aphid was shown to conform taxonomically and biologically to the recently named species Myzus nicotianae Blackman, except for its rare production of alatae. It is reported for the first time on greenhouse-grown potato where its population development is similar to that of the yellow holocyclic M. persicae from the same colony. The vector efficiency of the green and yellow aphids for potato virus Y0 is similar. The yellow aphid tends to be more susceptible to insecticides than the green aphid. Myzus nicotianae was not found in aerial aphid samples taken in New Brunswick in 1967 and 1987.