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AbstractIntroductions of some forest invasive alien species result in important economic, environmental, and ecological impacts. One approach used by the Canadian Food Inspection Agency to improve the detection of these species is to collect logs from trees in declining health at high risk sites of introduction and to incubate them to obtain insects, if present. Trichoferus campestris(Faldermann) (Coleoptera: Cerambycidae) adults emerged, and live larvae were extracted, from one of two logs taken from a dying Norway maple, Acer platanoidesLinnaeus (Sapindaceae), in Mississauga, Ontario, Canada. In its native range, eastern Asia, this beetle is polyphagous, however, in North America there is no host record despite numerous interceptions of larvae in wood packaging material and captures of adults at various post-entry sites. An examination of the feeding damage caused by T. campestrisin that maple suggests this insect is not a primary pest of trees in Ontario.

AbstractAn established population of the exotic woodwasp Sirex noctilioFabricius (Hymenoptera: Siricidae) was first detected in North America in 2004. In order to develop survey guidelines for the detection of this major pest of PinusLinnaeus species in the Southern Hemisphere, we examined 231 Pinus sylvestrisbiweekly to establish the timing and spatial distribution of resinosis symptoms of attack, and the timing of subsequent tree mortality. Fresh resin appeared between mid-July and late August, and on 70% of infested trees was observed on the mid bole. The occurrence of tree death varied between sites, from 2 weeks after the first detection of resinosis in one site to several months in seven other sites. Findings from our study provide key information to improve detection of S. noctilioand predict its impact on forest stands in its new range in northeastern North America.

AbstractA 2-year field study was carried out to locate and identify eggs, determine the temporal distributions of eggs and larvae, and assess the impact of Strobilomyia laricisand S. viariaon Larix laricina. Eggs of S. lariciswere beige with a patterned surface and usually laid one per cone in the bud scales at the base of the cone. Eggs of S. viariawere white and smooth and usually laid one per cone between the ovuliferous scales of the cone. Strobilomyia laricisoviposited from mid- to late May and S. viariafrom late May to mid-June, each species initiating oviposition at a different stage of cone phenology. Peak egg densities of S. lariciswere 25 and 65% higher than those of S. viariain 1990 and 1991, respectively. Larvae of both species completed development at the same time, from mid-June to early July. The mean number of scales eaten per cone did not differ between species; one larva damaged a mean of 8.4 scales per cone in 1990 and 10.7 scales per cone in 1991. As the number of scales per cone increased, the mean number of scales eaten increased and the mean percentage of scales eaten decreased. Cone crops were light in both years. In 1990, the only year we were able to differentiate cone maggot larvae, 44% of cones were damaged by S. laricisand only 16% by S. viaria. Together, S. laricisand S. viariadamaged 60 and 67% of the cones and destroyed 38 and 50% of the potential seed crop in 1990 and 1991, respectively.

AbstractThe life cycle of Strobilomyia appalachensisMichelsen, a maggot exploiting black spruce seed cones, was studied in two plantations in northern Ontario in 1987 and 1988, and two seed orchards in New Brunswick in 1991 and 1992. Oviposition by S. appalachensisoccurs slightly later than the white spruce cone maggot, S. neanthracinaMichelsen, relative to seed cone development; otherwise the life cycles of the two species are similar. Adults were trapped near host foliage in May and early June. Eggs were laid between the scales of seed cones during early June, starting when the scales on most cones were closed and ending 1 week after cones were fully pendant. Up to five eggs per cone were observed but single eggs were most common. The first larval molt occurred within the egg chorion and second-instar larvae emerged from the egg. Second-instar larvae were found in the cones during the 2nd and 3rd week of June, and third instars from the 3rd week of June until mid to late July. Larvae tunneled around the cone axis and destroyed an average of 60% of the total seed per cone before exiting and dropping to the soil. Larval drop occurred from late June to late July and was significantly correlated with periods of rainfall. Mature larvae moved into the duff and overwintered in the soil as pupae. Aspects of the maggot’s life history are discussed in relation to pest management strategies.

AbstractTwo species of cone maggots, StrobilomyiaMichelsen, are known to attack seed cones of spruces in North America. Seed cones of black, red, and white spruce from Newfoundland to Alberta were collected to determine the number of host species and the distribution of these maggots. Strobilomyia appalachensisMichelsen was obtained only from seed cones of black and red spruce, whereas S. neanthracinaMichelsen was obtained only from white spruce seed cones. Our observations represent the first record of S. appalachensisin Canada. We conclude that, like S. neanthracina, S. appalachensishas a transcontinental distribution, but exploits different hosts, namely black and red spruce. We also observed that S. appalachensiswas capable of extended diapause.

AbstractThe age at which Pseudaletia unipunctafemales initiated calling varied with temperatures experienced during pupal and adult stages. Entrainment was induced by temperatures during pupal development if similar to or lower than temperatures during adult life. However, adult temperatures were of major importance if lower than those experienced during pupal development. These observations were generally supported by data from field experiments repeated at different periods of the summer. The possibility that entrainment occurs at a specific period of development is proposed to explain certain field observations.Changes in mean onset time of calling and the time spent calling also varied, although generally not in the same manner as reported for other species. Differences in the life cycles, particularly the site of pupation, are proposed to explain these discrepancies.

AbstractThe spatial and statistical distribution of Zeiraphera canadensisMut. and Free. (spruce budmoth) within the crown of white spruce (< 4 m high) was investigated in northern New Brunswick. A 15-cm branch segment, measured distally from the scales of the branch’s apical growth and taken from the upper one-third of the crown, is considered an adequate sample unit for density estimates of spruce budmoth eggs and larvae. Sample sizes required to estimate spruce budmoth larval densities with given levels of precision and confidence were determined. A sequential sampling plan to classify spruce budmoth populations as low or high (potentially leading to growth reduction and deformed leaders in white spruce) was also developed.

AbstractThe relationship between the phenological development of the spruce budmoth (SBM), Zeiraphera canadensis, and that of its primary host, white spruce, was studied in New Brunswick using descriptive indices for both insect and host development. Larval emergence of SBM was synchronized with bud burst of white spruce, the species on which most eggs are laid. Subsequent SBM larval development can be estimated through reference to the development index for white spruce. For black, Norway, and red spruce, initial bud burst occurred approximately 15, 3, and 15 days, respectively, later than white spruce and this asynchrony is probably one of the reasons why the SBM is not an important pest on these tree species.

AbstractThe life cycle, feeding behavior, and feeding damage of the spruce budmoth, Zeiraphera canadensis, were studied in northern New Brunswick. Larval emergence, which began in late May, was usually completed within 10 days. First-instar larvae did not feed on the previous year's foliage and took less than 30 min to settle inside a growing shoot, from which they exited only at the end of larval development. Larvae then dropped to the ground and remained as prepupae for approximately 6 days. Mating could be observed the first night following adult emergence. The majority of the mated females contained only 1 spermatophore (92%); others had 2 (7%) or 3 (1%). Although 95% of the egg clusters had 7 eggs or less, 5% had up to 19 eggs. Eggs required embryonic development before successful diapause could be initiated. The importance of these observations in the development of management strategies for this pest is discussed.