Since 1970 the increasing level of Colorado potato beetle infestation in southwestern Ontario has necessitated foliage sprays or planting treatments with systemic insecticides. Spray tower tests of many insecticides against eggs, larvae, and adults indicated that the best overall materials would be carbofuran, azinphos-methyl, and chlorfenvinphos.

At planting time furrow treatments with granular carbofuran, disulfoton, or phorate demonstrated good control of all potato pests until the end of June. After that time only the carbofuran and phorate treatments gave protection against a heavy second generation of potato beetles. Yields were related to the degree of pest control.

An instance of medium-range migration by Rhopalosiphum maidis (Fitch) and of long-range migration by Spodoptera frugiperda (J. E. Smith) are documented and the weather systems that made the migrations possible are detailed. Although both species were carried beyond their northern limit for overwinter survival and little damage ensued, the usefulness of synoptic weather analysis in explaining sudden population increases is shown.

An attraction to certain plant species by Bombus terricola, B. bimaculatus, B. perplexus, and B. ternarius was observed. The gathering of pollen was observed as a behavioural act distinct from nectar gathering. Pollen analyses indicated that pollen collectors restricted their activities to a small number of plant species. These bees’ life histories and flower preferences made them potentially effective pollinators of early-flowering economic crops, Ribes spp., and Pyrus Malus in particular, and of common weeds such as Solanum Dulcamara and Hypericum perforatum. The same reasons prevented them from being important in the pollination of Trifolium pratense and Medicago sativa.

Based on our studies with 10 geographic populations of Chrysopa carnea, we recommend that biological control programs involving this predator use "pure" carnea stock originating from eastern and midwestern North America. Of the two strains (races or biotypes) of C. carnea—carnea and mohave—carnea is the superior choice for biological control on commercial crops in both eastern and western North America because (1) its preoviposition period is approximately one-half as long as mohave’s, (2) unlike mohave adults, neither sex of the carnea strain requires prey for successful mating and initiating oviposition, (3) carnea’s oviposition can be enhanced in the field by applying currently available food sprays, and (4) carnea is efficient to mass-rear on a commercial basis.

The “pure” mohave race is restricted to limited areas on the west coast. This race, which can enter a food-mediated summer diapause, is more suitable for biological control on the west coast in non-agricultural situations dominated by native vegetation, where prey occurrence is highly variable during summer.

Most west coast populations in agricultural areas are composed of intermediates between the carnea and mohave races. F1 hybrids produced by crossing individuals from mohave, carnea, and intermediate populations, show predominantly carnea characteristics, and inheritance of the distinguishing biological traits appears to be controlled by polygenes.

In outdoor cage studies undertaken in the late summer of 1973, a method of estimating the absolute density of a stable fly (Stomoxys calcitrans (L.)) population was developed by correlating the average number of insects feeding or resting on a calf to the total number in the cage. Under the same cage conditions, where emigration, immigration, and to some extent, predation have been excluded, the daily mortality rate of normal stable flies marked with a fluorescent dye ranged from 25.3% to 27.3% dependent upon the sampling technique. Marker dyes have a deleterious effect on survival but surprisingly gamma irradiated flies succumbed at a lower rate than normal individuals.

Eight new nearctic deltocephaline leafhoppers are described and illustrated: Palus beirnei, Rosenus pendulus, R. decurvus, R. transarcticus, Laevicephalus saskatchewanensis, Flexamia satilla, Deltocephalus serpentinus, and D. mystax. All known nearctic species of Palus and Rosenus are illustrated and keyed.

The larva, adult female, and adult male of Chrysomelobia labidomerae n. sp. are described. The adult female is compared with that of the only other described species in the genus, C. mahunkai from Europe. Chrysomelobia labidomerae is a parasite of adult milkweed leaf beetles, Labidomera clivicollis (Coleoptera: Chrysomelidae), in North America. Morphological similarities of all stages of Chrysomelobia with those of the generalized podapolipid Dorsipes support the retention of Chrysomelobia in the Podapolipidae as a most primitive genus in that family and the only one with 4 pairs of legs in the adult female.

Adult females of Chrysomelobia labidomerae Eickwort lay eggs on the upper surfaces of the hind wings of Labidomera clivicollis (Kirby). The eggs hatch in approximately 7 days and male and female larvae feed at the base of the wings and in the meso–metathoracic crevice and swell to about twice their original length. For about the second half of the approximately 7-day larval stadium, the larvae are inactive (pharate adults) and are usually cemented to the undersurfaces of the elytra. Inactive female larvae are accompanied by adult males that apparently copulate with the newly emerged adult females. The pharate adult is enclosed in a cuticular sac that may represent a calyptostatic nymphal instar. Adult females feed on the beetle’s abdominal terga and sometimes also occur on its venter where they do not feed. Females disperse from host to host when the beetles copulate. The species is arrhenotokous. Mites overwinter on the diapausing adult beetles and do not infest the immature stages of their host. Even at high population levels, the mites do not noticeably affect the longevity or fecundity of their hosts.

The first adult generation of Winthemia rufopicta (Big.) emerged during April in North Carolina, males preceding the females by about a week. This was several weeks prior to the occurrence of large larvae of Heliothis zea (Boddie) and H. virescens (Fab.), two commonly recorded hosts of W. rufopicta. The average female, after a pre-ovipositional period of several days, deposited about 60 eggs over a further several days. The sex ratio was normally unity, with the exception that flies overwintered in the field showed a predominance of males.

Populations of W. rufopicta declined in spring, apparently from a shortage of hosts, then slowly built up through several overlapping generations: developmental rates at different temperatures are indicated. In the fall, local host concentrations were more frequent, and parasitism of Heliothis hosts on tobacco occurred consistently and sometimes reached high levels. Parasites overwintered as fully grown diapausing maggots in shallow cells in the soil.

Experimental populations of Heliothis spp. (mainly H. virescens) maintained on tobacco were not parasitized by W. rufopicta until late in the season. Temporal and spatial interactions between host and parasite populations at that time are discussed.

Short-term interactions of the polyphagous tachinid Winthemia rufopicta (Big.) with its hosts, especially Heliothis zea (Boddie) and H. virescens (Fab.), are considered.

Within a given host species, interacting factors fall into three groups: (1) factors that have little influence on parasite oviposition, or cause little parasite mortality (host responses to ovipositing parasites, previous parasitism, firmness of attachment of eggs and, in the populations studied here, direct competition with other insect parasites); (2) factors that may account for significant limitation of oviposition (habitat, diel activity, and seasonal occurrence of a given host, and species preference of the parasite) or that cause significant parasite mortality (destruction by the host and other mortality of hatching maggots, which in turn depends partly on the position of eggs on the host): and (3) factors that can vary widely in a given host species and are therefore of great potential importance. These are: (a) host feeding behaviour—initial parasitism of H. zea, for example, varies from negligible levels for larvae concealed in corn ears to sometimes very high levels for larvae feeding openly on tobacco leaves; (b) host size—smaller larvae (especially penultimate compared with final instars) receive fewer ovipositions, and fewer eggs per oviposition; (c) host moulting—surface-deposited eggs are lost if the host moults before they hatch, but the rate of moulting varies with instar and foodplant, and interacts differently with parasite egg incubation times at different temperatures (most eggs are lost except in final instars); (d) intraspecific competition—depends on parasite and host densities, but reaches the highest levels in the fall; (e) competition with host pathogens—parasites may be killed during development if the host dies from pathogens.

For different hosts, family, size, surface quality, and spatial and temporal availability are known to have divergent influences on the levels of parasitism, but many other interactions are probably important.

The interpretation of records of total or of successful parasitism in host samples is considered—behavioural, developmental, and numerical interactions may make conclusions drawn from such records unreliable. In particular, levels of parasitism may change very rapidly as host or parasite populations develop; laboratory rearing may distort recorded levels of successful parasitism; and the proportion of attacked hosts that produce parasites, and the number of parasites produced by each host, normally varies directly with the number of eggs per host even when this is large.

Benomyl controlled cabbage maggot, Hylemya brassicae (Bouché), on potted cabbage plants in a greenhouse when applied as a drench 3 days or 3 hours before eggs were introduced. It was not effective when applied 2 days or more after eggs were added or when the plants were transplanted from treated to untreated soil before eggs were added. The results suggested that the action of benomyl was ovicidal.