The new association approach for selecting biological control agents has been reanalyzed in the light of recent data. The results support the conclusion that the new association approach is ecologically and statistically sound. One of the major advantages of this approach is its capacity to control native pests, which make up 60–80% of all pests. The specificity of biocontrol agents newly associated with the target hosts is similar to other biocontrol agents. In addition, the new association approach is as safe as the old association approach in terms of environmental risks. Recent trials in the use of new associations have been most encouraging, and suggest that this approach should contribute to the future success of biological pest control worldwide.

Resistant potato plants influenced the parasitoid Edovum puttleri Grissell directly, as well as indirectly through eggs of the parasitoid’s host, the Colorado potato beetle, Leptinotarsa decemlineata (Say). In the field, E. puttleri parasitized more egg masses on plants with no glandular trichomes or with glandular trichomes bearing only enclosed droplets of exudate than on plants with two types of glandular trichomes (one with exposed droplets and the other bearing enclosed droplets). Trichomes with exposed droplets entrapped numerous parasitoids. Although rearing L. decemlineata on resistant plants influenced many of the beetle’s life-history traits, it did not affect the suitability of their eggs for development and survival of preimaginal E. puttleri. However, eggs from L. decemlineata that were reared on resistant potato plants reduced the longevity of the parasitoids and also reduced the number of hosts (eggs) killed by parasitoids.

The striped pine scale, Toumeyella pini (King), had three generations per year in south Georgia. Females developed on snoots and males developed on needles of loblolly pine, Pinus taeda L. Generations overlapped and crawlers were most abundant in May, mid-July to early August, and late October to early November. The average fecundity was 1865 crawlers per female. Parasitism averaged ca. 15%, but the predation rate reached 50%. Coccophagus lycimnia Walker (Hymenoptera: Aphelinidae) was the most common parasitoid reared from both males and females. A pyralid larva, Laetitia coccidivora (Comstock), was a frequent predator of females.

The first of a planned series of papers revising the Nearctic species of the predaceous diving beetle genus, Agabus Leach, is presented. The genus is defined in the broad sense of Sharp (1882) and Fall (1922). The North American species are divided into species groups and diagnostic characters for group recognition are summarized in a key. Assignment of species to these groups is indicated in a checklist of North American species. The ambiguus-, tristis-, and arcticus-groups are defined, their relationships discussed, and included species revised. The ambiguus-group, which is restricted to North America, contains the species A. ambiguus (Say), A. strigulosis (Crotch), A. erythropterus (Say), A. austinii Sharp, and A. klamathensis sp.nov. The tristis-group, which has a Holarctic distribution, contains two species in North America, A. tristis Aubé and A. leptapsis (LeConte). The Holarctic arcticus-group is represented by A. arcticus (Paykull) and A. anthracinus (Mannerheim) in North America. For each species, patterns of variation are described, the North American distributions mapped, and ecological information summarized.

The incidence of diapause in pupae of the second (overwintering) generation of the carrot rust fly, Psila rosae (Fab.), at the Holland Marsh, Ont., was determined at intervals during fall and spring of 1982–1983, 1984–1985, and 1985–1986, by placing pupae collected from carrot plantings at developmental temperatures in the laboratory. The percentage of samples in diapause increased with time of sampling from late September on, until 100% of the pupae collected in late November or early December were in diapause. The percentage in diapause of pupae overwintering in the ground of an insectary at Jordan Station, Ont., decreased from January onward until, by early April, diapause was virtually absent. In spring collections from the Holland Marsh, some evidence of diapause was detected in the earliest samples, indicating that diapause is a factor that should be considered when degree-day models are being developed for the carrot rust fly.