Larval densities and catch of adult male Choristoneura fumiferana (Clemens) in pheromone-baited covered funnel traps in the same year were highly correlated. Such traps avoid saturation problems associated with conventional sticky traps. Release of marked males resulted in recapture rates of up to 21% in covered funnel traps. The findings suggest that non-saturating pheromone-baited traps could be used to monitor population densities and trends of the spruce budworm.

Some interspecific and interpopulation Lepidoptera and Orthoptera hybrids show a syndrome of developmental abnormalities referred to here as the “sequence effect.” In normal within population broods of Lepidoptera males develop slightly faster than females, but in crosses showing the sequence effect, females in one direction of the cross develop faster and in the reciprocal cross much more slowly than their male siblings. In some cases the environmentally induced diapause of the females may differ strikingly from that of their male siblings. Development rate and diapause in these species appear to be controlled by a sex-linked coadapted gene complex. Expression of the sequence effect may result from a loss of a species- or population-specific balance between regulatory and secretory portions of this complex, resulting in hormonal abnormalities which are more likely to be expressed in the heterogametic sex (females in Lepidoptera, males in Orthoptera).

Intrapopulation size variation was studied by means of length measurements quoted in taxonomic literature and from material of various groups of Coleoptera collected in the field. The degree of variation was significantly different among groups, and generally the free-living groups had lower intrapopulation size variation than most of the tree-boring and the parasitoid groups. Several tree-boring groups (e.g. Scolytidae, Curculionidae), however, had a comparatively low variation. A high intrapopulation size variation is common in species whose larvae are unable to choose and determine their own nutritional situation. Such larvae have a restricted mobility and the quality of their food is unpredictable. This is characteristic for most of the tree-boring groups. A high size variation increases the niche width of the species and probably has a buffering effect in unpredictable environments. Those tree-borers that are able to reduce the degree of unpredictability (i. e. by parental care, specialization in choice of microhabitat and in larval morphology, as in Scolytidae) have a rather low intrapopulation size variation. There are two possibilities regarding the genetic nature of the high size variation: (1) The population contains a variety of phenotypes with genetically fixed size, and (2) each individual is flexible with the possibility of becoming large or small depending upon the nutritional conditions. Possibility (1) is in agreement with the theories of a correlation between environmental heterogeneity and a high intrapopulation genetic variation. Free-living species and those tree-borers with less intrapopulation size variation are usually subject to more uniform conditions, and if adverse conditions do arise, these species usually fail to complete their development rather than produce smaller adults.

Twenty-four species of winter stonefly, 8 Taeniopterygidae, and 16 Capniidae, are known from southern Québec; three species, Allocapnia indianae Ricker, A. rickeri Frison, and Taeniopteryx maura (Pictet), are new Québec records. An analysis of the geographical distributions indicates four faunal elements: 6 ubiquitous species occurring over most of the northeastern part of the continent, 4 boreal species, 4 Appalachian species, and 10 species originating from the Mississippi Valley. Except perhaps for Capnia vernalis and C. manitoba, most seem to have survived the glaciations in eastern refugia and have migrated back into Québec along the slopes of the Appalachians. Characteristic species associations can be recognized. In small slow and eutrophic streams of the upper St. Lawrence Valley and the lower Ottawa Valley, Allocapnia granulata and A. vivipara predominate; in the small spring-fed streams of the same area, small populations of A. recta can develop. In highland water courses, a clear zonation is established: headwater streams usually harbour no species; in small streams, capniids, particularly A. illinoensis, Paracapnia angulata and the ubiquitous A. pygmaea, dominate; in larger streams, more capniids are added, such as A. minima, A. pechumani, and P. opis, together with the taeniopterygid T. burksi; in rivers, taeniopterygids abound (T. nivalis, T. parvula, and Oemopteryx glacialis), while the capniids become rarer, A. minima and A. pygmaea. In large lowland rivers, only A. minima and O. glacialis still survive. On the North Shore, boreal elements, such as C. vernalis, Utacapnia labradora, and Taenionema atlanticum, are added or substituted in midsized streams, while in the Eastern Townships, this is true of the Appalachian species A. maria, A. rickeri, and T. maura.

The adults of many Lepidoptera augment carbohydrate and protein reserves accumulated during larval life by feeding on nectar or sap flows. However, the adults of other species have non-functional mouthparts. The feeding behaviour of the species in a particular family or subfamily tends to be stereotyped. Thus in some taxa nearly all of the species have functional mouthparts in the adult stage, while in other taxa the mouth-parts are aborted. In those taxa whose adults feed, eggs are nearly always laid singly or in pairs. By contrast a significant proportion of the species whose adults fail to feed lay their eggs in clusters. This shift in egg laying behaviour can be explained by recognizing that an increased proportion of the energy reserves stored during larval life can be directed towards egg production if females engage in limited flight.

The invaginated apical abdominal segments of both sexes of Vanhornia eucnemidarum Crawford are described and illustrated for the first time. Detailed illustrations of the ovipositor and phallic structures are also given. No synapomorphy was found to associate Vanhornia and the Proctotrupidae, so because of its unique structure Vanhornia is left as an independent family of Proctotrupoidea.

Adults of Geayia ontarioensis n. sp. are described. Members of this species exhibit character states of the tibia of the pedipalp and of the legs characteristic of Geayia (s.s.), but differ from all other members of the subgenus in having 5 rather than 4 pairs of genital acetabula. A revised diagnosis of Geayia (s.s.) is presented.

A suction trap operating 1.4 m above ground and sticky traps arranged from ground level to 7 m were used to collect flea beetles during 1979–1982. The suction trap showed a peak in flight activity for Phyllotreta striolata (F.) in late April and May, but caught few beetles later in the season. The same trap showed that Phyllotreta cruciferae (Goeze) commenced flying a few days later than P. striolata, but continued to fly through the summer. The highest catch of P. cruciferae occurred in late August and early September. Prior to early June more flea beetles were caught on sticky traps at 1 and 2 m than on traps at ground level or 0.5 m. Subsequently more were caught at the two lower elevations. Beetles were captured on sticky traps up to the highest trapping height of 7 m throughout the growing season. These data suggest that the average flight elevation and level of flight activity are highest until the beginning of June for both species and then drop, and that P. cruciferae usually flies more actively and at higher elevations than P. striolata.

Overwintered P. cruciferae flew only when daily maximum temperatures exceeded 14 °C. The new generation of adults was captured flying in August and September when daily maximum temperatures were as low as 4.7 °C. Throughout the season, the catch in a suction trap was negatively correlated with average wind speed.

Given the extended flight period of P. cruciferae, late seeding of canola would not prevent invasion of the crop by this pest. Day to day variation in beetle catches by sticky traps or a suction trap, and trap to trap variation for sticky traps was high. Therefore, such traps would not provide sufficiently precise estimates of flea beetle densities prior to seeding to permit farmers to determine whether a field requires a seed treatment.

Mandibles of females of 10 species of mosquitoes from five genera; hypopharynx of females of 26 species from 11 genera; and laciniae of females of 31 species from 14 genera, were examined using scanning electron microscopy. Mandibular teeth are present in Anopheles and Armigeres females, but absent in Aedes, Culiseta, and Culex. Interdigitating cuticular projections are present at the tip of the hypopharynx in all females examined. The salivary canal is open both at the tip as well as dorsally along a longitudinal slit. The average number of lateral teeth on the maxillary stylets varies according to species. Mesial and vestigial teeth are present in some species. There is no correlation between number of maxillary teeth and specific hosts of mosquito species. The function of stylet structure in feeding is discussed.

A sequential decision plan, based on the negative binomial distribution and providing for two infestation classes, has been derived for use in management of the alfalfa blotch leafminer, Agromyza frontella (Rond.), in southern Ontario. It utilizes counts of the eggs in leaflets of alfalfa, and in economic situations will provide growers with sufficient lead time to consider alternative action strategies. An appraisal of the plan by field scouts showed that it rated the infestation status of the leafminer correctly in 48 of 51 cases. Sampling time averaged 25 min per scout per field.

Parathion-resistant (R) (× 24) onion maggot (OM), Delia antiqua (Mėigen) (Diptera: Anthomyiidae), adults showed 15-, 9.3-, and 7.7-fold levels of cross-resistance to direct contact applications of chlorpyrifos, naled and chlorfenvinphos, respectively, when compared at the LD50 with an insecticide-susceptible OM strain. R OM also showed 3.4-, 2.9-, 1.6-, and 1.3-fold levels of resistance to deltamethrin, permethrin, cypermethrin, and fenvalerate, respectively. The low-level resistance to the pyrethroids was probably conferred from DDT, to which the R OM strain had a 4.7-fold resistance level. Nevertheless, deltamethrin, cypermethrin, fenvalerate, and permethrin were 137, 58, 28, and 17 ×, respectively, more toxic to the R OM strain than was parathion.

Required sample size was determined for early instar (2nd to 4th instar) larvae of spruce budworm, Choristoneura fumiferana (Clem.). Larval counts on mid-crown 45 cm branch tips and whole branches of balsam fir, Abies balsamea (L.) Mill., were described in terms of the negative binomial distribution. The values of common k for the branch tip and whole branch sample units were 1.550 and 1.636, respectively. The required sample size at densities greater than or equal to one appears feasible. It is recommended that the 45 cm branch tip be used to estimate population density of early instar larvae in Newfoundland.

Public participation in home vegetable gardening and small farm operations is increasing in North America. This is expected to intensify the use of insecticides and disproportionately increase public exposure to them. For instance, von Rurnker et al. (1972) estimated that on an area basis homeowners in the midwestern United States applied ca. 5.0 lb of pesticides per acre. This amount when compared with 1½ to 3 lb per acre applied by the farmer suggests that backyard gardens receive a heavier pesticide application than most other land areas in the United States. It is, therefore, important to develop ecologically less aggressive control methods for small farm operations.

Rhinocyllus conicus Froelich was introduced from Europe into Canada and the United States for the biological control of Carduus thistles (Kok 1981). Although several reports indicate that the larval and pupal stages of R. conicus are parasitized by native hymenopterous parasites (Dowd and Kok 1982; Puttler et al. 1978; Rees 1977; Surles 1974) and by mites (Goeden and Ricker 1977) in the USA, no native parasite attacking eggs or adults of R. conicus has ever been reported. However, in 1981 and 1982, flies emerged from puparia formed beside field collected adult R. conicus which were maintained in the laboratory. Three specimens were obtained and identified as Hyalomyodes triangulifer (Loew) (Diptera: Tachinidae). This is the first native nearctic parasite known to attack adult R. conicus.

Insecticides are often applied immediately prior to bloom on apple to control various pests. While extensive reviews (Johansen 1977; Standifer 1977) of the toxic effects of these materials on honey bees are available, little is known of their “repellent” effect (van Praag 1980), which might result in reduced flower visits and hence less efficient pollination. Little information is also available on the direct effect of insecticides on pollination and fruit set.

Trichosirocalus (= Ceutorhynchidius) horridus (Panzer), introduced from Italy into the USA for the control of Carduus thistles in 1974/75, is well established in Virginia (Kok and Trumble 1979). Field studies on the development of this weevil on Carduus thistles in Italy (K. E. Frick, USDA, Stoneville, Mississippi — pers. comm; Boldt and Campobasso 1981) and in Virginia (Trumble and Kok 1979) revealed that weevil eggs were commonly found in rosettes during the winter months. In Virginia, first instars were detected in rosettes immediately after the snow melted (Trumble and Kok 1979). Therefore, the eggs are exposed to the coldest temperatures in January and February when air temperatures reach −20°C in western Virginia. The effects of such temperatures on the proportion of hatch and on the viability of the hatchlings are not known. In addition, T. horridus has consistently laid the maximum number of eggs in November and December in the laboratory for the past 10 years. Thus, a large supply of thistles had to be grown in the greenhouse to support the weevil population during the winter when plant growth was poor and mortality of laboratory reared T. horridus was high. In any successful biological control program the proper time of release of the beneficial organism as well as numbers available is critical. Successful storage of T. horridus eggs would greatly increase the number of T. horridus available when needed for inoculative releases or experimental purposes. The purpose of this study was to determine suitable temperatures and storage times for T. horridus eggs without affecting hatch and viability.

Okra, Abelmoschus esculentus (L.) Moench, is a member of the Malvaceae. It is an important crop in the southern United States where vegetable production becomes precarious during the summer owing to extreme conditions of temperature and drought. Okra is grown in most southern home gardens and is consumed as a main dish vegetable or used in soups and gumbos.

Because of its popularity and environmental adaptability, okra may have the potential for attracting fresh market premium prices for limited resource farm operations. However, little has been published on insect pests of okra in the United States. In an investigation at Petersburg, Virginia, during 1979 and 1980, we found that the corn earworm, Heliothis zea (Boddie), was an important pest of okra.

In a previous investigation on the effects of sublethal doses of fenitrothion (O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioateo)n the tobacco hornworm, Manduca sexta (L.), it was found that the treated larvae developed asynchronously, required more time to reach the pupal stage, and had larger bodyweights than the control larvae (Stewart and Philogène 1983). Regressive moults, faster pupal development, and shorter longevity of the adults were also observed. The impact of sublethal doses of insecticides on subsequent generations of insects has, however, received limited attention. We now present experimental evidence that the progeny of treated insects can also show some of the characteristics described above, an observation that may have significant consequences in the field.

Eurasian water milfoil, Myriophyllum spicatum Linnaeus, was introduced into eastern North America late in the nineteenth century. It has spread and developed into a major aquatic weed in many areas of the United states and Canada (Aiken et al. 1979; Reed 1977). In British Columbia, it was first observed in the Vernon Arm of Okanagan Lake in 1970 and had spread to all major 1,akes in the Okanagan Valley by 1976 (Newroth 1979).

Members of the pulcher–undulatus species group of Hydroporus Clairville (sensu Fall 1923) were rearranged as follows by Wolfe and Matta (1981): (1) H. pulcher LeConte and 12 other species (each with a bifurcate aedeagal apex) were assigned to the subgenus Heterosternuta E. Strand; (2) H. pilatei Fall and H. triangularis Fall were revised and assigned to a new genus, Falloporus; (3) and the remaining approximately 35 species were placed in the subgenus Neoporus Guignot.