Studies were carried out in the field and in the laboratory to determine if prolonged diapause of the Douglas-fir cone moth, Barbara coifaxiana (Kearfott), was correlated with the sizes of the cone crops maturing in the year of larval feeding (N) and in the year following larval feeding (N + 1), and to determine if weather during the period of larval feeding (year N) influenced the size of the maturing cone crop or the incidence of prolonged diapause the following year (N + 1). Field studies showed that prolonged diapause induction in B. coifaxiana was not rank correlated (but approached significance) with the size of the cone crop maturing in year N, but was negatively rank correlated with that in year N + 1. Two of seven weather parameters, mean maximum temperature and mean daily temperature, measured during the larval feeding period were positively rank correlated with cone crop size. No parameter was correlated with the incidence of prolonged diapause. In the laboratory, the incidence of prolonged diapause was negatively correlated with temperature. Photoperiod and parental diapause habit had no direct effect.

Female Colorado potato beetles fed foliage of Solarium tuberosum of the Russet Burbank variety infected with potato leafroll virus have lower fecundity and shorter longevity than those fed virus-free foliage. Also, female beetles prefer feeding on foliage infected with potato leafroll virus. This observation could be of importance in the development of resistant varieties of potatoes to potato beetles.

Laboratory tests showed that nymphs of the migratory grasshopper are very sensitive to diflubenzuron (Dimilin) when reared continuously on treated wheat seedlings or artificial diet and fresh lettuce. At concentrations of 10 ppm or above, diflubenzuron completely inhibited moulting of 2nd-instar nymphs. With continuous exposure on treated wheat seedlings, the LC90 values after 8, 12 and 20 days were 10.0, 2.4 and 0.8 ppm, respectively. Comparable values were obtained with the artificial diet and lettuce. However, when 2nd instars were placed on diflubenzuron-treated wheat foliage for 1 day then transferred onto untreated plants, toxicity declined markedly.

Although the toxic effects of diflubenzuron were delayed, dry weight determinations on wheat seedlings indicated that nymphal feeding damage was insignificant if the plants had been sprayed with 10 ppm diflubenzuron.

The implications of these findings are discussed in terms of the potential field use of diflubenzuron against stationary and mobile grasshopper nymphs.

The pea aphid, Acyrthosiphon pisum (Harris), affected yield by significantly reducing the mean height of aphid-susceptible Grimm alfalfa in a greenhouse experiment by 45%, the height of the longest stem by 35%, the green weight by 38%, the dry weight by 44%, and the fiber by 13%. There was limited change in quality of alfalfa. The percentages of protein, fat, total sugar, reducing sugar, dry matter, and nitrogen-free extract were not significantly different in the infested and non-infested alfalfa. Potassium was significantly lower in the infested plants but they contained more calcium, magnesium, and phosphorus. With the exception of isoleucine the amino acid composition was similar in the infested and non-infested alfalfa.

The effects of sequential attack on gallery construction, oviposition, and reemergence by Dendroctonus frontalis Zimmermann were studied in the laboratory at 25 °C. Six mating pairs were allowed to attack bark slabs in groups of 2 pairs every 2 days. Total gallery and eggs per pair decreased with increasing day of attack. The time of attack had little effect on the distance and time from the gallery origin to the first egg. Distances between eggs were shortest for pairs attacking second and greatest for pairs attacking last. Inverse relationships of egg-bearing gallery length, oviposition period, and adult residence time were observed with the day of attack.

The basic behavioral and physiological mechanisms thought to influence reproduction of D. frontalis are discussed. A hypothesis for termination of oviposition is formulated from these mechanisms, which provides greater understanding of the effects of attack density on reproduction.

Electrophoretic characterizations of sibling species in the Simulium venustum–verecundum complexes are presented based on nine enzymatic loci. Simulium verecundum s.l. is easily separable from S. venustum s.l. by unique complements of electromorphs for lactate dehydrogenase. Quantitative and minor qualitative differences also exist between most pairs of sibling species within S. venustum and S. verecundum. Not all pairs are separable using the nine enzymatic loci scored in this study. This close genetic affinity of species pairs that are not separable by electrophoretic methods parallels their chromosomal and ecological affinity.

Fifteen months after an intense forest fire, the fauna of carabid beetles in burnt and unburnt sites was sampled using pitfall traps to detect the indirect effects of fire on carabids caused by habitat change. Traps were installed in burnt and unburnt sites in which the dominant tree species before the fire was either spruce or aspen. The most commonly caught species was Pterostichus pensylvanicus which was captured more frequently in unburnt sites, but was not affected by dominant tree species; a similar pattern of distribution of captures was found for Carabus taedatus. Harpalus laticeps was captured only in burnt sites. P. lucublandus and Dicaelus sculptilis upioides were most commonly caught in the unburnt aspen site, while Pterostichus adstrictus was most commonly caught in the burnt spruce site.

Female Culex tarsalis Coquillett trapped in CO2-baited light traps or reared from field-collected pupae were marked with fluorescent dust, released, and recaptured in traps baited with CO2 with or without light. Recaptures of trapped females peaked on the first night of recapture collections. Recaptures of reared females peaked on the first or second night when autogeny rates were low (25–44%) but 2-4 nights later when rates were high (86–88%). It was concluded that autogenous females did not seek blood until after they had oviposited, and that autogenously induced delays in feeding probably influence the extent of virus transmission by C. tarsalis.

Stretched follicular tubes indicating recent oviposition were found in 23.4% and 5.2% of empty parous females from shelters and CO2-baited traps, respectively, and in 2.3% of freshly engorged parous females from shelters. Females often failed to blood-feed until at least the second night after oviposition.

UC-62644, a moult-inhibiting insect growth regulator (IGR) belonging to the benzoylphenylureas, had an EC50 of 0.1 to 0.2 ppm in a meridic diet for the 3rd to 6th larval instars of the spruce budworm, Choristoneura fumiferana Clemens. The effects of the IGR were apparent in less than 48 h after ingestion and there was evidence for some contact toxicity. The larvae were unable to discriminate between IGR-treated and untreated diet. Experimental aerial application of the IGR revealed that at <70 g in 4.7 1/ha (1 oz in 0.5 U.S. gal/acre) it effectively controlled spruce budworm populations and afforded foliage protection. These results were comparable with those obtained with Matacil® applied at the recommended rate.

Head capsule widths were measured on 962 larvae of Rhyacionia rigidana (Fernald). Five instars were detected using multimodal analysis, and normal distributions of head widths for each instar are given. Regression using an exponential growth model was used to generate mean head widths according to Dyar's rule. These widths did not differ significantly from observed widths.

The life cycle of Corticeus glaber (LeConte) was investigated at 25 °C and 60% R.H. The developmental time from egg to adult for C. glaber ranged from 30 to 41 days and five larval instars were determined from head capsule measurements. The mature larva is described.

The spruce beetle, Dendroctonus rufipennis (Kirby), causes periodic, widespread mortality of mature spruce (Picea spp.) in western North America (Massey and Wygant 1954; Schmid and Frye 1977). In British Columbia, logging of infested stands and felling of trap trees are the commonly recommended methods for preventing or suppressing spruce beetle outbreaks. Implicit in these methods is the requirement of treating infested logging residue, and removal for processing of trap trees after the attack period of the spruce beetle. The usual treatment for infested logging residue, prescribed burning, is difficult to carry out in most years because of the generally wet climate of spruce forests during the growing season and the fall period. The forest industry questioned whether burying infested logging residue would be effective in preventing emergence by the spruce beetle. The work described herein addressed this question.

In 1958 I reported finding the European geometrid moth Perizoma alchemillata (L.) on the Avalon Peninsula of Newfoundland. This yas based on seven specimens collected in 1954 in the general vicinity of St. John's, but in places several miles apart, suggesting that the species was already well established. That was the first record of this species for North America. Morris and Bolte (1977) discussed its further spread in Newfoundland, summarized what was known about its food plants and distribution elsewhere, and gave illustrations of adults and genitalia. By 1975 it had become common on the Avalon Peninsula and was known from Lethbridge in central Newfoundland and Tompkins in western Newfoundland. Eleven adults were collected at Tompkins, 2-31 July 1975. Morris (1980: 241; pl. 29, fig. 26) again treated this species, adding Stephenville and St. Georges to the list of localities, indicating that additional material had been collected in southwest Newfoundland between 1975 and 1980. In 1959 and 1962 I collected intensively in the region of the Codroy Valley in southwest Newfoundland, covering the season from June to mid-August, and found no indication of its presence then; nor did I see it in a large collection made by Akira Mutuura in the Codroy Valley in July 1968 (Canadian National Collection).