Ceutorhynchus litura (F.) (Coleoptera: Curculionidae) is established since 1967 in Ontario, and is increasing slowly on nine release sites in five provinces. The weevil is not a good control agent because its reproductive capacity does not compensate for losses inflicted by cultivation and the stress resulting from larval mining is so light that it produces no noticeable reduction in the vigour of Canada thistle (Cirsium arvense (L.) Scop.). In contrast to earlier findings, it is doubtful that C. litura aids in the spread of the rust Puccinia punctiformis (Str.) Rohl. Further stress factors from other insects or pathogens are needed to control this vigorous weed.

Laboratory studies showed that elm leaf beetle, Pyrrhalta luteola (Müller), larvae and pupae were susceptible to the nematode Neoaplectana carpocapsae Weiser; adults were less likely to be infected because of their dispersal ability. Spruce budworm, Choristoneura occidentalis Freeman, larvae were susceptible to the nematode in the laboratory. Field application of the nematode in 2% aqueous Volck oil suspension against elm leaf beetle or spruce budworm larvae did not significantly reduce the populations when compared with controls. Desiccation of the infective nematodes may be a factor in the variable results for elm leaf beetle, and cool temperatures and rain may have been factors in the poor results for spruce budworm. However, significant population reduction occurred in nematode treatments against elm leaf beetle pupae in litter. This nematode may be used against beetle pupae in conjunction with other control tactics.

Eggs of the red turnip beetle, Entomoscelis americana Brown, were exposed to temperatures of 0°, −5°, −10°, −15°, and −20°C for 1–8 wk and for 200 days in the laboratory. At −5° and −10°C, there was no death attributable to the cold treatment. At −20°C, the cold treatment caused approximately 15% mortality in the 6- to 8-wk samples and 100% mortality in the 200-day samples. At 0° and −15°C, mortality in the 200-day samples was 39% and 23%, respectively. The data indicate that the embryos of E. americana are able to withstand cold temperatures for long periods and that the optimum temperature range for hibernation (between 0°C and −15°C) is similar to the one this beetle normally experiences in the subnivean air space once the hiemal threshold is established. For Canada, an evaluation of the snow cover and atmospheric air temperature data suggested that egg mortality due to exposure to temperatures of −20°C or lower in the subnivean air space should not occur in the various parts of the red turnip beetle’s range, except possibly the grassland region of the Prairie climatic zone.

Discovery of new external structures permit easier separation of species of Phymatocera for both sexes. A key is given and a phylogeny is reconstructed for all species. The name P. rusculla (MacGillivray) is a junior synonym of P. offensa (MacGillivray).

Under laboratory conditions, Corticeus glaber (LeConte) and C. parallelus (Melsheimer) adults were facultative predators of southern pine beetle, Dendroctonus frontalis Zimmermann, eggs and first and second instar larvae. Southern pine beetle frass and blue stain fungus, Ceratocystis minor (Hedgecock) Hunt were also suitable for survival for both species of Corticeus. Loblolly pine (Pinus taeda L.) phloem was not utilized as a food source by either species. Corticeus spp. larvae were predators of D. frontalis eggs.

The developmental rates of individual larvae of Tribolium confusum Jacquelin duVal were measured at five temperatures on three diets to quantify the interaction between these two environmental factors. No significant differences in survival were detected but developmental times were affected by both factors. A logistic equation accurately described the relationship between mean developmental rate and temperature for each diet. The variance in developmental rate was a linear function of the mean developmental rate, and the mean accounted for more of the differences in variance than diet or temperature.

The effect of diet was greatest at the temperature which caused the highest developmental rate. It decreased as temperature decreased. This effect could be accounted for by varying the coefficient K, the asymptote of the logistic equation. The coefficient K showed a positive linear relationship to the lysine content of the diet. This coefficient may provide a compact and quantitative means of summarizing the interaction of environmental factors such as diet and temperature in the logistic model for the developmental rate of insects.

A new spray application system which mimics the spray deposit of aerial applications of chemical insecticides was developed and tested using acephate at the rate of 60 g a.i./L (U.S. Environmental Protection Act registered dosage) on small Douglas-fir and subalpine fir trees infested with western spruce budworm. The system successfully duplicated aerial application by causing a budworm population reduction equivalent to previous aerial tests having analogous insecticide deposit characteristics. Using the system, preliminary information was gained on the effectiveness of sulprofos and thiodicarb. When delivered at a rate of 4.1 L/ha, sulprofos caused a budworm population reduction of 86.2% at 22.4 g a.i./L and thiodicarb caused a reduction of 98% at 45 g a.i./L.

Variables affecting the efficacy of seven juvenile hormone analogues on western spruce budworm, Choristoneura occidentalis Freeman, were examined in laboratory bioassays. Those tested were epofenonane, hydroprene, kinoprene, methoprene, triprene, ZR-587, and ZR-1662. Selected intrinsic variables—stage of development, sex, and extent of direct contact with sprays—were examined in bioassays involving direct exposure of third instars, direct applications to three pupal age classes, and indirect applications to sixth instars. An extrinsic variable, persistence in the environment, was assessed by determining the residual effectiveness of each juvenile hormone analogue to sixth instars. Sixth instars, rather than third instars, appeared to be the target of choice for two reasons. First, less active ingredient would be required for equivalent mortality by the time of adult eclosion. Second, greater, more consistent, deleterious reproductive effects coupled with a lower incidence of sexual variation in lethal effectiveness, would occur. Pharate pupae and untanned pupae were very susceptible to most of the chemicals and may provide a secondary target for the primary target, sixth instars. The importance of direct chemical-insect contact in achieving maximum reproductive inhibition suggests that these chemicals might be used most effectively in ways such that contact can be maximized, as in ground applications. Finally, some juvenile hormone analogues such as epofenonane and ZR-1662 appeared to persist long enough to permit flexibility with respect to instar distribution in a population.

Two geographical biotypes (G and A) of Heliothis zea Boddie were identified in a constant temperature laboratory study. The G (Georgia) biotype was found to have a mean development rate 5 ± 1% faster and coefficient of variability 44 ± 9% higher than the comparable A (Arizona) biotype. Each geographical biotype was described by a biophysically based, nonlinear development function with an R2 equal to 0.995. At temperature ranging from 15.6° to 35.6°C, the adult emergence distributions transformed to a physiological age scale were shown statistically to be independent of temperature. They could be described by a “same shape” distribution function. The empirical same shape distribution for rate was not significantly different from a hypothetical normal distribution.

The genetic make-up of representative populations of five Choristoneura species was compared using starch gel electrophoresis. Species included C. occidentalis Freeman from Idaho, C. biennis Freeman from British Columbia, C. retiniana (Walsingham) (= C. viridis Freeman) from Oregon, C. lambertiana ponderosana Obraztsov from Colorado, and C. fumiferana (Clemens) from Maine. When variation at individual gene loci was examined, intraspecific variation was often as great, and sometimes greater, than interspecific variation and few significant differences were noted among the species. The highest levels of overall genetic similarity occurred among C. occidentalis, C. biennis, and C. retiniana. Relatively greater genetic distances were found between this group and C. lambertiana and C. fumiferana. C. fumiferana was most distantly related to all other groups. Genetic identity values fell within the range more commonly associated with conspecific populations rather than with separate species.

Biosteres melleus (Gahan), Diachasma alloeum (Muesebeck), D. ferrugineum (Gahan), Opius canaliculatus Gahan, O. downesi Gahan (all Braconidae), and an undescribed Psilus sp. (Diapriidae) emerged from puparia of Rhagoletis pomonella (Walsh) collected in Connecticut during 1977 and 1978. Percentage parasitism ranged from 7.9 to 36.8% in flies on hawthorn and from 0.0 to 23.9% in flies on apple. It exceeded 5.0% in only 5 (22.7%) of 22 samples from apple. Higher rates of parasitism usually occurred at sites where other hosts of apple maggot parasitoids probably infested fruits on nearby plants.

While preparing the Agrilus portion for a handbook on the Buprestidae of Canada and Alaska, an item of nomenclatural interest was discovered. I wish to thank Dr. G. H. Nelson, Pomona, California for his review of this note.