Larch sawfly oviposition activity as revealed by scarring of long shoots of eastern larch, Larix laricina (DuRoi) K. Koch, was measured at various locations in the high boreal forest and forest tundra in Québec in 1988 and 1989. The data show that larch sawfly is established up to the tree line, even on isolated larch growing under climatic conditions that are extreme for this tree. Frequency distributions of scarred shoots as a function of time suggest thai larch sawfly populations reached outbreak levels in the 1980s, with peak numbers in 1981 for the high boreal, and in 1985 for the subarctic regions sampled. Trends in long shoot production by larch trees started to fluctuate simultaneously with the sudden increase in larch sawfly populations along the Grande Rivière de la Baleine in 1984. In this region in 1985, the proportion of long shoots used by Pristiphora erichsonii averaged 20–35%, which may have limited further population increase. Although foliage reduction and branch mortality were observed, mortality of whole trees was not a general characteristic of this outbreak.

Orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a major economic pest of wheat (Triticum aestivum Linnaeus). Here, we review its general biology, history of global spread, economic impact, and methods available to manage its populations. Outbreaks have been reported across the Northern Hemisphere, including in China, Japan, the European Union, the United Kingdom, the United States of America, and Canada. Predators and parasitoids can help attenuate these outbreaks, but control has relied mainly on use of foliar insecticides. Wheat cultivars with resistance to midge conferred by the Sm1 gene became commercially available in 2010 and increasingly are grown to manage midge populations. Forecasting models have been developed in different countries to predict wheat midge populations in an effort to mitigate the degree of economic damage by supporting wheat cultivar selection and to optimise the timing of insecticide applications in conventional wheat production systems. Conservation of natural enemies, insecticides, resistant cultivars, and models combine to form effective integrated pest management programmes for midge, illustrated for Canada with a decision-making flowchart. Future work is needed to address the likely development of midge biotypes with resistance to the Sm1 gene and insecticides currently in use.

The spruce budworm Choristoneura fumiferana (Clem.) is the most damaging insect of the balsam fir Abies balsema (L.) Mill. (Pinaceae) and the white spruce Picea glauca (Moench) Voss (Pinaceae) throughout eastern North America. In outbreak conditions, close to 100% tree mortality can occur in untreated mature fir stands (MacLean 1980). Bacillus thuringiensis var. kurstaki (Bacillaceae) is currently used to reduce spruce budworm damage (Van Frankenhuyzen and Payne 1993). Other possible biological control agents, such as baculoviruses, are also investigated to complement the use of B. thuringiensis. Baculoviruses are advantageous because they occur naturally in several insect species and are generally host specific (Federici 1993).

During the summer of 1951, a number of full-grown larvae of the European corn borer, Pyrausta nubilalis (Hbn.), that died while being held in cold storage lor experimental use at the Entomology Laboratory, Chatham, Ontario, were forwarded to the Kingston laboratory for diagnosis. Microscopic examination showed that the dead larvae cnntaincd a hard core of fungous mycelium.

The micro-organisms that accur in insects may be pathogenic, nonpathogenic, supposedly or actually beneficial, or casual invaders. The literature on the various aspects of the subject has become extensive (Buchner, 1953; Fraenkel, 1952; Shrewsbury and Barson, 1954a, 1954b; Steinhaus, 1946, 1949).

Population growth and dispersion of Tetranychus mcdanieli McGregor were studied in an experiment conducted on Red Delicious apple trees grown in a light and temperature controlled walk-in growth room. Lloyd’s index of mean crowding was calculated as a means of interpreting aggregation patterns; however, it was found that mean colony size was a more generally useful population parameter . The regression of on mean density (m) and the ratio of mean density to were used to determine and characterize the patterns of dispersion obtained under the experimental conditions of the study.

It was shown that the ratio of mean density to is the proportion of sampling units (i.e. individual leaves) that would have a colony size of individuals per unit, all other units being unoccupied. Characterization by the concomitant parameters and provides a more sensitive and meaningful method of describing populations than does the arithmetic mean.

The data indicated that adult female populations of T. mcdanieli tend to be distributed as clumped colonies on apple trees. A plant feeding mite damage scale was devised to evaluate the reliability and accuracy of gross observational estimates as indicators of spider mite levels.

Seventeen species of Plecoptera were collected from 58 lakes situated along the Continental Divide in southwestern Canada. Four of the 17 species were found once. The commonest species was present in 25 lakes. At low to middle elevations stoneflies occurred in large lakes that had relatively low total dissolved solids and low maximum annual heat content. The distribution of the majority of species was restricted with respect to lake area and elevation. For example, some species were found only in large lakes at low to medium elevation (900 to 1700 m), while others were found only in small lakes at high elevation (1800 to 2400 m).

Periphyllus pusillus n. sp. from Acer villosum Wall., Serratocallis takahashii n. gen., n. sp. from Quercus sp., and Myzocallis (Hoplocallis) microsetosus n. sp. from Quercus incana Roxb., collected in the Western Himalayas, are described. The taxonomic position of the aphids is discussed.

Three allopatric species are recognized in the North American genus Tegrodera LeConte. Speciation was probably a relatively recent event in this genus as all species are closely related, and separable by minor but consistent differences of adult anatomy. The most distinctive species, T. aloga Skinner, ranges throughout much of the Sonoran Desert in western Arizona and northwestern Sonora. T. erosa LeConte, a species occurring in southern California and Baja California, is separated geographically from T. aloga by the arid Colorado Desert. T. erosa consists of two distinct subspecies, the nominate form occurring in southern California, and T. e. inornata Blaisdell distributed throughout much of Baja California. T. latecincta Horn, a species found in the Owens and Antelope valleys of California, is the closest relative of T. erosa. It is separated from the latter by the San Gabriel and San Bernardino mountains, and from T. aloga by the vast Mojave Desert. The species of Tegrodera are each associated with different plant communities, though the genus Eriastrum seems to be an important food source for all adults. The taxonomic analysis presented herein includes the study of both intra- and interspecific variation. The first instar larva of T. aloga and T. e. erosa are compared, and notes on seasonal distribution, habitat, and non-sexual behavior are included.

Adult apple maggots, Rhagoletis pomonella (Walsh), were relatively free from attacks by predators in southern Ontario. The main reason for this was the flies’ alert avoidance of approaching objects. In addition to this protection from predators, the flies appeared to be avoided by hunting spiders. Adults of the cherry fruit fly, Rhagoletis cinqulata (Loew), were equally alert and apparently free from predation while they were in apple trees.

Based on data collected at seven constant temperatures, a temperature- and age-dependent model for reproductive development and oviposition by Diabrotica barberi Smith and Lawrence was developed. The model couples temperature-dependent rate and temperature-independent distribution models to represent the observed variability in developmental times for pre-reproductive, reproductive, and post-reproductive females. Using a cohort approach to maintain a physiological age structure, development was coupled with a temperature- and age-dependent model of oviposition. The model was validated at one constant-temperature and three variable-temperature regimes in the laboratory. The time spent in the pre-reproductive stage was slightly underestimated by the model, but the development of mature females and both the timing and magnitude of oviposition under fluctuating-temperature regimes were accurately predicted. The model was relatively insensitive to errors in estimation of the rate of development in the pre-reproductive stage but sensitive to errors in estimation of developmental rate of the reproductive stage and fecundity. Errors in input temperatures were found to be very important, stressing the need for accurately measuring temperature, The major driving variable. The model should be a valuable aid toward understanding oviposition by D. barberi in the field.

During 1961 and 1962 observations were made on the activities of predators of the pear psylla, Psylla pyricola Förster, in the Okanagan Valley of British Columbia. Attacking the psylla together, the anthocorid bug, Anthocoris melanocerus Reuter, and the green lacewing, Chrysopa oculata Say, gave more effective suppression than either predator alone. DDT and Diazinon drastically reduced numbers of these predators b commercial plantings. In non-sprayed, isolated orchards, trace numbers of these predators maintained effective control of pear psylla populations.

A key is given to the three genera of the Phloeocharinae. Full generic descriptions with comparative and distributional notes are given for Rimulincola Sanderson, Vicelva paradoxica new genus, new species, Ecbletus Sharp, and Olisthaerus Dejean.

We tested the prediction that larvae of the fir coneworm, Dioryctria abietivorella (Groté), preferentially exploit cones previously damaged by cone maggots, Strobilomyia spp. In most years sampled, fir coneworm attacked a significantly greater proportion of maggot-damaged than healthy cones of both white spruce and black spruce. The ecological implications for pest management are briefly discussed.

The silver-spotted tiger moth, Halisidota argentata Pack., is a potentially dangerous defoliator of Douglas fir in British Columbia. Natural control factors have always prevented populations from building up to destructive proportions.

The literature contains little information on this insect. Fletcher recorded the first outbreak of what was probably H. argentata in British Columbia in 1887 (2). Moths were identified as H. sobrina Stretch, but this form is now recorded only from California so it was probably H. argentata. The outbreak, probably on southern Vancouver Island, was reported as “committing great depredations on the spruces here.” Mathers found H. argentata at Chilliwack in the Fraser River Valley in 1934, but there was no report of an outbreak (4). A few larvae were collected on southern Vancouver Island from 1936 to 1952. In 1953 a considerable number of colonies were observed, and the following year the silver-spotted tiger moth was in infestation proportions. In 1955 the outbreak increased in intensity, and spread northward to the limit of its known range. A survey in the spring of 1956 failed to find a single colony south of Lantzville, and the population in the northern portion of the range was greatly reduced.

Cylas formicarius (F.) shows a strong overall sexual monomorophism, with external differences noted in only three organs: (a) relative size of the hind wings; (b) form of the antennal club and numbers of its different types of sensillum; and (c) size of the compound eyes and their individual facets. We relate these to known or predicted behavioural differences. Eye dimorphism is used to test a theoretical rule on the relationship between differences in overall eye size and in the size of individual ommatidia. Some sexually monomorphic features are briefly discussed, including two types of putatively sensory hairs not found on the antennae.

We examined rates of late-season parasitism of larvae of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), by native species of Bracon F. (Hymenoptera: Braconidae) over 8 years in Montana and North Dakota, United States of America. We found that rates of parasitism of larvae in diapause chambers reached a maximum of 46%, exceeding the previously reported maximum of 2.5% in 75% of sites and years examined. In contrast to previous work, our results demonstrate that C. cinctus larvae are suitable hosts for braconid parasitoids, even after the formation of diapause chambers, and suggest that parasitism rates may be underestimated if stems are sampled prior to harvest.

Rates of development of selected stages and complete development of the carrot weevil, Listronotus oregonensis (LeConte), were determined in the laboratory at controlled temperatures ranging from 17.5 to 30°C. Within that range of temperature, rates of development increased with temperature. Fitting the data to a cubic polynomial function provided an excellent description of the relationship between temperature and rate of development for all stages as shown by R2 values of at least 0.98.

The lily leaf beetle, Lilioceris lilii (Scopoli) (Fig. 1), was first noticed in Portage la Prairie (49°58′N, 98°20′W), about 90 km west of Winnipeg, in June and July 1999. The beetles were present on Asiatic lily varieties only, especially tiger lilies (Lilium tigrinum Ker-Gawl (Liliaceae)). Larvae and adults were observed at two locations in the northeastern section of the town. The plants that were attacked were completely defoliated.