Types of cages and methods for rearing, collecting, holding, and scheduling adult emergence are described for hymenopterous parasites of Coleophora laricella (Hübner). Methods differ depending on whether the parasite attacks needlemining larvae, e.g. Agathis pumila (Ratz.) and Diadegma laricinellum (Strobl), or casebearing larvae, e.g. Chrysocharis laricinellae (Ratz.), Elachertus argissa (Walk.), Necremnus metalarus (Walk.), Dicladocerus westwoodii Westw., and Dicladocerus japonicus Yshm. Biological details of the parasites pertinent to laboratory rearing include stage attacked, developmental times, adult longevity, diapause, mode of reproduction, progeny sex ratios, and suggested parasite/host ratios.

Extracts of eight species of freshwater vegetation were tested for toxicity against larvae of Aedes aegypti L. All extracts were found to be toxic. The same extracts and culture water from one of the species were also tested for their possible influences on the oviposition behaviour of A. aegypti. Extracts of six species repelled ovipositing females; one extract and the culture water attracted ovipositing females; and one extract type had no influence on the oviposition behaviour.

Five species of whiteflies (Aleyrodidae) were found on citrus in southern Texas: Aleurocanthus woglumi Ashby, Aleurothrixus floccosus (Maskell), Paraleyrodes citri Bondar, Dialeurodes citri (Ashmead), and D. citrifolii (Morgan). Parasite records for this area were Amitus hesperidum Silvestri (Platygastridae) and Prospaltella opulenta Silvestri (both Encyrtidae) attacking A. woglumi; Eretmocerus sp. near paulistus Hem. (Encyrtidae), Amitus sp., and Prospaltella sp. attacking A. floccosus; and Prospaltella sp. attacking P. citri. Predators recorded were Delphastus pusillus (Le Conte) (Coccinellidae) feeding on A. floccosus; D. pusillus and Nephaspis amnicola Wingo (Coccinellidae) feeding on P. citri. A pathogenic fungus, Aschersonia aleyrodis Webber, was found attacking D. citri.

The predatory behavior of Lonchaea corticis Taylor on the white pine weevil, Pissodes strobi Peck, in Sitka spruce, Picea sitchensis (Bong.) Carr., was studied by temporal sampling and dissection of terminal leaders, and by laboratory experiments. L. corticis oviposition occurred when mining P. strobi larvae were consolidating the feeding ring, an event that segregates the weevil larvae into healthy front-feeders and weak, starving "followers." The number of L. corticis within a Sitka spruce terminal was highly correlated with the number of weak and dying P. strobi larvae, but not with healthy larvae.

L. corticis larvae experimentally deprived of dead P. strobi larvae, behaved as an effective predator, consuming both weak P. strobi larvae and healthy pupae, but apparently not healthy larvae. The transition of L. corticis from second to third instar appeared to occur only after sufficient weevils had been consumed. When an excess of prey was present, L. corticis larvae consumed a mean of 2.9 P. strobi pupae over their entire life cycle. In choice experiments, L. corticis larvae searched for and located mining P. strobi larvae, and fed preferentially on P. strobi pupae rather than granary weevil pupae, Sitophilus granarius L. Under certain circumstances, L. corticis could be an important regulatory agent of P. strobi populations.

A new bioassay unit is described which provides simulated stream conditions for testing control agents against black fly larvae. Attributes include uniform flow, high control survival, and excellent visibility for observing larval behavior. It also possesses the unique advantage of using recycled water, continuously supplied fresh water, or both simultaneously. The unit has performed satisfactorily in assays against black flies using pathogens, parasites, and chemicals. In addition, stream invertebrates from four insect orders have been maintained in the unit.

A simple and inexpensive incubation unit is also described which possesses several of the advantages of the bioassay unit. It lacks the capability for recirculation and is generally less versatile than the bioassay unit; however, it is useful for the maintenance and observation of stream insects.

Mature Telrastichus julis (Walker) larvae, which overwinter in the pupal cells of their dead cereal leaf beetle hosts, enter diapause in late summer. Diapause is maintained by warm conditions and short daylengths during late fall and early winter; it ends without a specific terminating stimulus. Subsequently the larvae remain in a state of postdiapause quiescence until soil temperatures rise above 9 °C, the theoretical threshold (t) for postdiapause development. Emergence of the central New York population occurs when the parasites have accumulated 162 degree days (D°) of heat above 9 °C. This K value is considerably lower than that previously reported for a population from Michigan.

Our study provides the first experimental evidence that both temperature and photoperiod regulate the rate of diapause development in a parasitic insect.

The rise and decline of two infestations of Aphis barberae Robinson on the thistle Cirsium arvense (L.) Scop, are described. The larger infestation consisted of 122 colonies in an area 8 m in diameter and produced many alatae before declining. The second infestation consisted of 12 colonies and produced no alatae. Each infestation appeared to arise from a single central colony and spread when alate and apterous aphids travelled short distances to adjacent plants. The growth patterns indicate that each infestation represented a single clone. Both infestations declined rapidly due largely to predation and became locally extinct early in the summer.

The genus Acerotella of the Nearctic region is studied. Six species are recognized, all new to science: A. acerina ♀ ♂ (Canada, U.S.A.), A. aceris ♀ ♂ (Canada), A. depressa ♀ (U.S.A.), A. gouleti ♀ ♂ (U.S.A.), A. nearctica ♀ ♂ (Canada, U.S.A.), and A. vockerothi ♀ (Canada). The generic diagnosis of Acerotella and key to Nearctic species are given. The higher classification, species-groups, and world distribution of Acerotella species are discussed.

A laboratory bioassay technique using adult Drosophila melanogaster was developed to measure the vapour toxicity and sorption by soil of seven insecticides. The laboratory results were then compared with those from field trials measuring the effectiveness of the same insecticides in protecting potatoes from wireworm attack. There was sufficient agreement between the laboratory and field tests to indicate that the laboratory bioassay may be useful for screening insecticides preliminary to field wireworm control studies. Of the newer ’insecticides tested, fonofos, terbufos, and chlorpyrifos in descending order of efficacy, gave substantial protection from wireworm damage.

Granular treatments of thiofanox (Dacamox 10 G®) and carbofuran (Furadan 10 G®) and spray treatments of dimethoate (Cygon 4E®) and pirimicarb (Pirimor 50 WP®), all gave good control of cereal aphids and increased barley grain yield significantly above controls.

The granular treatments did not significantly reduce parasites and predators of the aphids. Predators and parasites showed a reduced population 1 week after foliar insecticide applications. However, pirimicarb showed a relatively reduced effect compared with other pesticides on the available predatory species, 2 weeks after spraying.

The compound tris (1-aziridinyl) phosphine sulphide, known by the trivial name thiotepa, has been tested against few aphids. Considerable reduction in fecundity occurred due to thiotepa treatment of the cabbage aphid, Brevicoryne brassicae (L.) (Bonnemaison 1966). In 0.3% thiotepa-treated Aphis fabae Scop. a 90% decrease in reproductive capacity was observed by Steffan and Stüben (1976). Sharma and Thériault (1980) tested 0.5% thiotepa on various nymphal instars of the pea aphid, Acyrthosiphon pisum (Harris), and observed up to 83% decrease in fecundity of those treated in first and second instars. The third and fourth instar aphids were much less influenced by thiotepa. The effects of thiotepa on the adult viviparae of the pea aphid are unknown and nothing has been recorded on the transmissibility of thiotepa-caused sterility to progeny. Further to the results of Sharma and Thériault (1980) this paper describes the effects of two contact periods with 0.5% thiotepa on the adult viviparae of A. pisum and delayed effects on subsequent generations.

In studies of the southern pine beetle, Dendroctonus frontalis Zimm., on loblolly pine, Pinus taeda L., one of the theories about the mechanism of attack is a shift in sex ratio from 100% to 25% females (Renwick and Vité 1970). This paper reports a test of this theory using trees that were naturally infested.

Thirty-one naturally infested loblolly pine trees were observed in July 1978, near Cut-and-Shoot, 19 km east of Conroe, Montgomery County, Texas. A 0.66 m quadrat was marked off on the bole of each tree at heights of 3 m and 3.66 m. Gallery starts in the quadrat were counted and marked every 24 h on each tree. The quadrat was reduced to a 0.33 m section on the bole at heights of 3.33 to 3.66 m on a tree after the attack density reached 1 gallery/100 cm2 and to a 0.16 m section at heights of 3.50 and 3.66 m on the bole after the attack density reached 2 gallerys/100 cm2; this facilitated timely counting and stabilized error due to observer fatigue.

The apple maggot, Rhagoletis pomonella (Walsh), is an indigenous North American insect whose principal native host is hawthome, Crataegus (Bush 1966). During the past ca. 120 years, this insect has expanded its host range to include fruits of the following introduced plants: apple, Malus sp. (Walsh 1867); domestic plum, Prunus sp. (Herrick 1920); sour cherry, Prunus cerasus L. (Shervis et al. 1970); apricot, Prunus armeniaca L. (Lienk 1970); and pear, Pyrus sp. (Prokopy and Bush 1972). Continuous populations have been established on apple and sour cherry, but apparently only occasional infestations occur on plum, apricot, and pear. Here, we report yet another new host of the apple maggot: the introduced rose hip, Rosa rugosa Thunberg