Oviposition by Trichogramma californicum Nagaraja and Nagarkatti into physiological saline encapsulated in paraffin droplets is influenced by the concentration of the liquid, population density of the parasite, and the addition of sugars, vitamins, and amino acids. Oviposition occurred within a concentration range of 0.43–1.28% NaCl, but there was no significant difference in the number of eggs deposited. Chances of oviposition generally increased with the increase of population density of the parasite and a minimum density of T. californicum females was required for oviposition. A phenomenon of enhancement, such that oviposition in any one vial is confined to one of the three droplets exposed, is recorded for certain media. However, this phenomenon was removed by addition of RNA, casein hydrolysate, or by use of Grace’s tissue culture medium without insect plasma and Grace’s modified medium with bovine and egg derivatives. Eggs deposited into 2 paraffin droplets containing modified Grace’s medium developed to the second instar larval stage.

Egg masses of the forest tent caterpillar, Malacosoma disstria Hübner, were collected from new and old infestation areas of northern Minnesota before development started in the spring. Mortality of embryos was recorded after laboratory exposure to −10°, −15°, −20°, −25°, and −30° C for 12, 24, and 72 hours at 1, 2, 3, and 4 days before anticipated hatch. Length of treatment and temperatures of −10° and −15°C had minimal effect on survival. Mortality of embryos varied with days before hatch in an erratic cyclic pattern with temperatures and years. Temperature treatments of −20°, −25°, and −30 °C caused about 50%, 66%, and 100% embryo mortality. Mortality in new infestation areas was consistently higher than in older areas for all treatments.

Four insecticides effectively controlled the pea aphid, Acyrthosiphon pisum (Harris), but differed in their effects on other pest species and on predators. Two days after treatment, methidathion, dimethoate, and malathion reduced populations of all the pest species, but pirimicarb gave no control of the weevils Hypera postica (Gyllenhal) and Sitona scissifrons Say. Methidathion reduced populations of all predators, dimethoate reduced populations of all predators except Aeolothrips fasciatus (Linnaeus), and malathion reduced populations of all the predators except Nabis alternates Parshley. Pirimicarb reduced only the populations of syrphids. Of the insecticides tested, methidathion was the most disruptive to predators and pirimicarb the least.

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.

Seven species of mites (Acari: Tarsenomidae) were associated with two local outbreaks of the southern pine beetle, Dendroctonus frontalis Zimmerman, in Chiapas, Mexico; three of these species were new records for Mexico and Central America. The morphology and phoretic behavior of these mites differed little between the western and southern populations from the United States. One major difference was that the hyperphoretic ascospores of the southern pine beetle mycangial fungus, Ceratocystiopsis sp. (Ophiostomataceae), were common in sporothecae of Tarsonemus krantzi Smiley and Moser (Acari: Tarsonemidae) and Tarsonemus ips Lindquist in Chiapas, Mexico, whereas the ascospores of the blue stain fungus, Ophiostoma minus (Hedgcock) H. and P. Sydow (Ophiostomataceae), were rare; this situation in the southern United States is reversed. The paucity of behavioral and morphological differences between the two southern pine beetle populations and the relevant historical climatology suggest that the appearance of D. frontalis in the southern United States may be a recent event.

Females of Heliothis zea (Boddie) were stimulated to produce pheromone by injection of brain – subesophageal ganglion homogenates. Females injected with this homogenate during the photophase produced the same amount of pheromone and same ratio of components as neck-ligated females injected during the peak of pheromone production. Decapitated females and isolated abdomens also produced pheromone when injected with the brain – subesophageal ganglion homogenate during the photophase. These data show that the neurohormone which stimulates pheromone production is not degraded by enzymes during the photophase and that pheromone is not metabolized at a greater rate during periods when the insect is not producing pheromones.

A reliable method for rearing the subterranean summer morph of the sugarbeet root aphid, Pemphigus betae Doane, is described. Field-collected aphids were reared using hydroponic growth pouches that allowed exposed root tissue to be fed on by P. betae. The aphid has been maintained in continuous culture for over 3 years. Open pouches were subsequently modified with cages to provide more successful mass rearing. Cages placed on the pouch were devised to provide an arena that concentrated aphids on one area of the pouch, minimized wandering behavior, and ensured a more vigorous colony. During a 10-week mass rearing experiment, caged pouches consistently averaged 120.8 ± 9.6(se) aphids per cage (fourth instars and adults) following 2-week incubation periods. Caged pouches also were used to isolate individual aphids for development and fecundity studies. Age-specific life tables were developed for P. betae using both open pouches at 20°C, and caged pouches at 24°C. Although the intrinsic rate of increase (rm) was lower at 20°C on a daily time scale (rm = 0.2314 versus 0.2591), rm was significantly greater at 20°C on a degree-day (DD > 7.6°C) time scale (rm = 0.0187 versus 0.0158). The difference on a DD basis resulted primarily from a longer time interval from birth to first reproduction (TFR) at 24°C(TFR = 158.5 versus 147.1 DD at 20°C). These results corroborate previous experience with P. betae, indicating that 20°C appeared to be an optimum temperature for mass rearing. Stable age distributions for P. betae cohorts were only slightly affected by temperature; on average approximately 55, 22, 11, 7, and 5% of the aphids were first, second, third, and fourth instars, and adults, respectively. Though similar studies have not been reported for other Pemphigus spp., all demographic statistics were characteristic of many foliar-feeding aphids held under similar constant temperature conditions.

This paper deals with the description of 14 new species of Caddis-flies from India and the Far East and belonging to the holarctic as well as to the oriental fauna.

The species described here as new are: Parapsyche denticulata and acuta from China, Parapsyche aureocephala and nigrocephala, Plectrocnemia nagayamai and tochimotoi, Psychomyia armata, Ecclisocosmoecus spinosus, Apatania ishikawai, Neophylax japonicus, Grammotaulius inornatus, Limnophilus nipponicus and Hydatophylax intermedius from Japan. Trichomacronema shanorum is Indian.

The shape of one single category of hemocytes served as a critically distinguishing character between larvae of two closely related species of Euxoa (Lepidoptera: Noctuidae) that were otherwise practically identical in external features. The ratio of length/width of fusiform plasmatocytes in heat-fixed blood films was significantly smaller in larvae of E. campestris (Grote) than in E. declarata (Walker).

A survey of the insect pests of carrots was conducted in the organic soils of southwestern Quebec with a view to establishing the presence of the carrot weevil, Listronotus oregonensis (Lec.), in this province as well as to confirm the importance of other pests damaging carrot crops. Four different methods were used to capture adults, and the root sampling method was used for establishing larval populations.The carrot weevil was captured by light trap for the first time in Quebec on 1 June 1967, but was neither recognized nor identified until June 1970 when a few specimens were obtained again by light trap set at Ste. Clotilde and by colour traps placed in the experimental fields used for the survey in 1970. Damage caused by this new pest on carrots ranged from 2.0% to 22.0% root injuries throughout the carrot growing areas of the organic soil regions of Sherrington, St. Michel, and Ste. Clotilde representing several thousands of acres. The carrot rust fly, Psila rosae (F.), was the only other carrot pest captured, but has been found to be of no importance in these areas.

The larvae of Rhinocyllus conicus Froel. feed within the flowerheads of Carduus nutans by tunneling through callus that appears near feeding sites, by forming chambers of callus beneath developing florets, or by tunneling within pith of the peduncle. The induction of callus by R. conicus is a gall-like response providing the larvae with additional nutriment and a shelter. Callus formation also reduces plant resources destined for developing additional flowerheads.

The effectiveness of the phytoseiid predator Neoseiulus fallacis in controlling population growth of the spruce spider mite, Oligonychus ununguis was examined in the laboratory. Development and fecundity of N. fallacis under various relative humidity levels were also studied. Under controlled conditions, N. fallacis significantly limited population growth of O. ununguis on Fraser fir seedlings. Survival, development, and fecundity of N. fallacis were similar for all relative humidity ranges tested, except at the lowest range (60–65%), in which none of the individuals survived to maturity.

Oocytes of queen bumble bees from southern Alberta were partly developed when the queens emerged from hibernation in the spring. Early emerging species had less autumnal ovariole development and fed longer in spring before establishing a nest than did later emerging species. The main increase in oocyte size was synchronous with the finding of a suitable nest. The mean length of the largest oocyte for workers for all species was small, less than 0.7 mm, clearly indicating that workers contribute few males to the population.

Abundance, persistence, and variability of populations of Macrosiphum euphorbiae (Thomas), Myzus persicae (Sulzer), and Aphis nasturtii Kaltenbach (Hemiptera: Aphididae) in potato plots for intervals of 58 years (n = 1), 29 years (n = 2), 19–20 years (n = 3), and 9–10 years (n = 6) were compared. The abundance of M. euphorbiae showed no trend among decades and varied 2.4-fold, whereas that of M. persicae and A. nasturtii declined and showed 54-fold and 3700-fold variation, respectively. All three aphid species persisted through the first five decades and M. euphorbiae also persisted through the sixth (last) decade, but M. persicae and A. nasturtii failed to persist for 1 and 3 years of the last decade, respectively. Population variability (a proportion between 0 and 1) measured over a 58-year interval was high: 0.585 for M. euphorbiae, 0.771 for M. persicae, and 0.830 for A. nasturtii. During the first three but not the last three decades, population variability increased with sampling interval, owing to dramatic declines in abundance for M. persicae and A. nasturtii and one stable decade for M. euphorbiae, but no evidence of a more-time — more-variation effect was detected. Persistence was not related to population variability, but declined with abundance. Populations did not reach equilibrium, because of declining abundance for M. persicae and A. nasturtii and changes in population variability from decade to decade for M. euphorbiae. Populations of M. persicae and A. nasturtii from this crop monoculture were less stable than previously studied natural populations of a native aphid species. In contrast, the population of M. euphorbiae, a native species, had variability in a potato crop similar to that of the previously studied native species. The high population variability of M. persicae and A. nasturtii may be associated with their status as introduced species. The dynamic and species-specific characteristics of population variability require that interspecific comparisons be considered cautiously.

Eggs of the red turnip beetle, Entomoscelis americana Brown, were exposed to temperatures of 0°, −5°, −10°, −15°, and −20°C for 1–8 wk and for 200 days in the laboratory. At −5° and −10°C, there was no death attributable to the cold treatment. At −20°C, the cold treatment caused approximately 15% mortality in the 6- to 8-wk samples and 100% mortality in the 200-day samples. At 0° and −15°C, mortality in the 200-day samples was 39% and 23%, respectively. The data indicate that the embryos of E. americana are able to withstand cold temperatures for long periods and that the optimum temperature range for hibernation (between 0°C and −15°C) is similar to the one this beetle normally experiences in the subnivean air space once the hiemal threshold is established. For Canada, an evaluation of the snow cover and atmospheric air temperature data suggested that egg mortality due to exposure to temperatures of −20°C or lower in the subnivean air space should not occur in the various parts of the red turnip beetle’s range, except possibly the grassland region of the Prairie climatic zone.

The present study was designed to investigate the influence of mate choice in terms of age on reproductive performance and offspring attributes of parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae). Age-based mate choice was most evident in the middle-aged adults. Results revealed that middle-aged males and females were significantly preferred as mates by their middle-aged counterparts. Younger and older females did not show any preference for males of any age group. On the other hand, younger males showed a bias against old females, while older ones did not show any age-based preference for mates. Both fecundity and percent egg viability were significantly influenced by female and male age, respectively. Fecundity was highest in middle-aged females followed by young- and old-aged ones, with similar trend observed in relation to male age effects on egg viability. The development and survival of immature stages borne out of mate choice decisions of adults was influenced by mother's age. Offspring of middle-aged females developed fastest and survived longer than those of younger and older ones.

A pilot black fly control program using Bacillus thuringiensis var. israelensis on a small stream system near St. John's, Newfoundland resulted in a 70% or greater population reduction of adult black flies from the previous year. The species present in the system were Prosimulium mixtum, Stegopterna mutata, Eusimulium vernum, Simulium tuberosum, S. venustum/verecundum complex, and S. vittatum. The formulation used was Teknar® flowable concentrate (Sandoz Inc.) rated at 600 ITU/mg which proved effective against the larval stages of all black fly species at a dose of 10 ppm for 1 min. The results indicated that this agent will be effective if applied at the appropriate locations and times. The 1-min dose was practical except in very cold water (0°–7 °C) where a 5-min or longer dose may be required. The unpredictable relief pattern of the northern streams resulted in a highly variable downstream carry for the B.t.i. Therefore application sites must be determined by a stream survey and not just from discharge characteristics.

A simulation model is described for the population dynamics of the European red mite, Panonychus ulmi (Koch). The model incorporates the following features: (a) development rate is dependent on effective daily temperature; (b) division of each population component into distinct daily age classes; (c) emergence of individuals from each population component is dependent on a log-normal probability distribution, and a temperature related development vector to accumulate a measure of the temperature effect on development. Validation runs on a mini-computer in 1976 and 1977 adequately described actual population curves determined from daily orchard sampling. A model of this type which can be used with small computers should prove useful in investigating the main factors affecting the population dynamics, and control strategies for this and other pests.

The emergence patterns of Diptera breeding in small-sized and buried carrion were studied in rearing experiments with field-exposed baits. Development times are reported for 52 species in the families Phoridae, Sphaeroceridae, Sepsidae, Heleomyzidae, Anthomyiidae, Fanniidae, Muscidae, Sarcophagidae, Psychodidae, and Sciaridae. Most species showed a synchronous emergence of males and females. Protandry was detected in Hydrotaea ignava (Harris) (Muscidae), H. palaestrica (Meigen), and Psychoda minuta (Banks) (Psychodidae). Protogyny was found in several species of Phoridae, namely Conicera similis (Haliday), C. schnittmanni Schmitz, Anevrina unispinosa (Zetterstedt), and Triphleba dudai (Schmitz). Conicera schnittmanni and T. dudai showed two discrete emergence periods for each sex, which is due to a delayed emergence of some specimens. Protogyny is a rare phenomenon in Diptera and insects in general, and has never been reported before in Phoridae. The significance of protogyny could not be ascertained in the examined species, because of insufficient information on their mating systems and female receptivity patterns.