Parapediasia teterrella Bleszynski adults eclose in New Mexico during the months of June, July, and August. Nightly emergence occurred within 40 min and this time period became earlier in the scotophase as the season progressed, particularly during July. The timing of this period does not seem to be related to either temperature or photoperiod.

Though males emerged before females on each night, sex ratios of emerging moths were consistently 1:1. Following a short sedentary period while their wings dried, the moths left the emergence site.

In 1989 and 1990, the contamination rate of the European pine weevil Hylobius abietis (L.) by several pathogenic fungi for the Scots pine was measured [Leptographium procerum (Kendrick) Wingf. — 45% of the specimens; Pachnodium canum (Upadh. and Kendr.) — 14%; or Ophiostoma piliferum (Fries) H. and P. Syd — 3% (Piou 1993)]. To understand the processes of transportation, a detailed study was conducted by scanning electron microscopy. Several types of spores vectored are found mainly in the thoracic cuticular rounded wells located near the sensorial setae. These wells are connected with an epidermal glandular apparatus whose ultrastructural description is given. We question the origin and composition of these secretions which are believed to protect the spores and contribute to the infection process.

The effects of timing of applications on the persistence of chemical and biologically active residues of clofentezine were tested on apple foliage during two seasons. Residues from prebloom and petal fall applications were less persistent than those in mid-season. Early season applications were toxic to European red mite for 7–21 days but mid-season applications were toxic for as long as 50–62 days. Chemical residue losses were also faster in the early season. Persistence of chemical residues was related to the rate of leaf growth and expansion. In 1991, foliage area expanded 244% per week during the prebloom period, 23% per week at petal fall, and 10% per week in July (mid-season).In a field test, applications of clofentezine at petal fall reduced European red mite populations within 7 days and mite numbers remained below economic thresholds for 6 weeks.

Laboratory studies of diapause induction in the horn fly Haematobia irritans irritans (L.) indicated that the incidence of diapause was unrelated to daylength or the number of day–night cycles. Transfer experiments were conducted to estimate the beginning and end of diapause sensitivity and the required number of days for diapause induction. On average, sensitivity was between the ages 0.10 and 0.82 on a physiological age scale of immature development. The number of days required for 50% diapause was estimated as 19.1 days. A model was developed relating the proportion of insects in diapause to the number of days spent in the interval 0.10–0.82. Additional experiments revealed that diapause in the puparia was related to the mean temperatures experienced by immatures during the interval of sensitivity. An equation relating the proportion in diapause to temperature was also developed and compared with the required day number model. Both models provided similar estimates of the proportion of horn flies entering diapause.

An investigation into the use of thresholds based on Cabbage Looper Equivalents (CLE) was conducted on Brussels sprouts, Brassica oleracea var. gemmifera (L.), cv. Valiant, grown in Prince Edward Island in 1991 and 1992. The CLE model was used to equate foliage consumption by larvae of the imported cabbageworm, Pieris rapae (L.), the diamondback moth, Plutella xylostella (L.), and the cabbage looper, Trichoplusia ni (Hübner). Management strategies included the following: (1) an untreated check; applications of insecticides after thresholds of (2) 1.0 CLE; (3) 0.50 CLE; or (4) 0.25 CLE per plant were exceeded; (5) bi-weekly applications of insecticides; and (6) applications of insecticides according to the grower’s spray schedule.In 1991, the imported cabbageworm was the most abundant species in the complex attacking the crop and high yields were obtained in all treatments. However, in 1992, the diamondback moth was the principal species and significantly reduced marketable yields in all treatments. Use of CLE as a model for threshold determination in the crop of Brussels sprouts underestimated the potential of the diamondback moth for damage and resulted in improper timing of applications of insecticide for adequate control of the diamondback moth.

Salignus distinguendus tahoensis (Knight) is raised to species status. All published records of the name S. distinguendus (Reuter) from North America are in error and are correctly associated with the name S. tahoensis. A diagnosis and key are provided to distinguish S. tahoensis from the Palearctic S. distinguendus and S. duplicatus (Reuter). The male and female genitalia and distribution of S. tahoensis are illustrated. The relationship between Oreolygus Linnavuori, Orthops Fieber, Pinalitus Kelton, and Salignus is discussed.

Spruce bud moth adults eclosed in mid-July and completed oviposition within a period of 2 weeks at 8- and 11-year-old white spruce plantations and at an old-field site in northern New Brunswick. Parasitism of bud moth eggs by Trichogramma sp. started less than 14 days after the beginning of adult bud moth eclosion and increased until the middle of August. The temporal patterns of egg parasitism and predation of viable bud moth eggs were similar in 1988 when most mortality occurred during the 2 weeks following the end of oviposition. At two sites studied in 1989, most parasitism occurred during the 4–5 weeks, and predation during the 1–3 weeks following the end of oviposition. Examination of temporal patterns of parasitoid eclosion and of the incidence of parasitism suggests that second-generation parasitoids attacked bud moth eggs at two of three sites. Depending on site and collection date, predators either showed a strong preference for unparasitized eggs or ate similar proportions of unparasitized and parasitized eggs. The incidence of egg parasitism and predation was not influenced by egg density in 1988. In 1989, a weak negative relationship between the number of eggs per cluster and the incidence of egg parasitism was not significant. However, a significant proportion of the variation in percentage egg parasitism was attributable to the interaction between egg density per shoot and collection date.

There are 16 species of Trichoclinocera Collin recognized from the Nearctic region, including eight new species. Four of six species-groups of Trichoclinocera are recognized in the Nearctic region, with the following included species: (1) T. comata group — T. cascadensis sp.nov. (type-locality Starvation Creek, Oregon, U.S.A.), T. comata (Melander) comb.nov., and T. rupestris sp.nov. (type-locality Newton Creek, Wyoming, U.S.A.); (2) T. dolicheretma group — T. dolicheretma (Melander); (3) T. lapponica group — T. lapponica (Ringdahl) comb.nov.; (4) T. longipes group — T. agilis sp.nov. (type-locality Fall Creek Falls, Tennessee, U.S.A.), T. ctenistes (Melander), T. dasycoxa sp.nov. (type-locality Ottawa, Ontario, Canada), T. falcata sp.nov. (type-locality Gatineau Park, Quebec, Canada), T. fumosa (Vaillant) comb.nov., T. hamifera (Melander), T. longipes (Walker). T. minor (Melander), T. ozarkensis sp.nov. (type-locality Haw Creek Falls, Arkansas, U.S.A.), and T. pectinifemur sp.nov. (type-locality Phoenixville, Pennsylvania, U.S.A.). The following new synonyms are proposed: T. brunnipennis (Melander) = T. dolicheretma; and Seguyella saltans (Vaillant) = T. hamifera. Lectotypes are designated for T. comata, T. ctenistes, T. dolicheretma, T. brunnipennis, T. hamifera, T. lapponica, and T. stackelbergi Collin. Seguyella Vaillant and Acanthoclinocera Saigusa are newly synonymized with Trichoclinocera and all species formerly placed in these genera are transferred to Trichoclinocera, except Acanthoclinocera glaucescens (Brunetti) which is transferred as Wiedemannia glaucescens (Brunetti) comb.nov.This revision includes a key to Nearctic species, a description of each species, and maps of species distributions. Homologies of male terminalia of Clinocerinae are summarized and the first descriptions of the immature stages of species of Trichoclinocera also are provided. A world list of described species of Trichoclinocera is provided and all species are assigned to one of six species-groups, except T. cummingi sp.nov. (type-locality Robber’s Cave, Oklahoma. U.S.A.), T. fluviatilis (Brunetti) comb.nov., T. fuscipennis Saigusa, and T. maewa Smith, which remain unplaced. The monophyly of Trichoclinocera is justified and phylogenetic relationships to the remaining Clinocerinae and among species-groups are discussed.

The relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.

Available information on the interaction between Sitka spruce weevil, Pissodes strobi (Peck), and its host Sitka spruce, Picea sitchensis (Bong) Carr., is examined. Based on a theoretical consideration of this information, a new mechanism is proposed to explain the resistance exhibited by some of the genetically distinct individuals of some provenances of this species. Experimental evidence is presented to show that resistant trees can sufficiently affect P. strobi reproduction and progeny development and survival to reduce this pest’s ability to kill the leaders of these trees when challenged with weevils containing already mature eggs. Our mechanism also provides an explanation as to how weevils are able to avoid attacking and reproducing on resistant trees in which their progeny would fail.

Rangeland grasshopper species richness was monitored at 10 sites in Montana, U.S.A., during 1986 through 1992, which included an extreme drought year (1988). We observed significant post-1988 drought reductions in rangeland grasshopper species richness in the eastern and south-central region of Montana where drought intensity has been increasing during the past 20 years. In the north-central region, which also experienced the 1988 drought but showed no long-term drought trend, we did not observe a post-drought reduction in overall rangeland grasshopper species richness. Thus, in terms of rangeland grasshopper species richness, the potential impact of a severe drought in a given year may depend on the timing of such an event within longer-term climatic cycles. Our findings suggest that as regional drought intensity increases temporally, there may be an increased likelihood that a single extreme drought year will not only have a profound impact on abundance but may also result in significant long-term reduction of grasshopper species richness. Our results support the hypothesis that resource limitation is a very important factor in structuring rangeland grasshopper communities in space and time.

Kalobittacus masoni, new species, and K. similis, new species, are described from tropical Veracruz, Mexico. Kalobittacus similis is compared with K. bimaculatus Esben-Petersen, the only Mexican species of Kalobittacus heretofore known. Males of all three species and females of the two new species are illustrated, and the species are differentiated in a key.

Shortly after the discovery of the introduction of balsam woolly adelgid, Adelges piceae (Ratzeburg), to the south coast of British Columbia, a predator release program was initiated to establish a complex of European and Asian adelgid predators to supplement existing native predators. Between 1960 and 1969, eight species of exotic predators, Aphidoletes thompsoni Mohn (Diptera: Cecidomyiidae), Cremifania nigrocellulata Czerny and Leucopis hennigrata McAlpine [=Leucopis sp. nr. melanopus Tanas. (McAlpine 1978)] (Diptera: Chamaemyiidae), Laricobius erichsonii Rosenhauer (Coleoptera: Derodontidae), Aphidecta obliterata (L.), Scymnus (Pullus) impexus Mulsant, and Scymnus (S.) pumilio (Weise) (Coleoptera: Coccinellidae), and Tetraphleps abdulghani Ghauri (Heteroptera: Anthocoridae), were released (Clark et al. 1971; Schooley et al. 1984).