Although Plutella porrectella (L.) is similar in appearance to the diamondback moth, P. xylostella (L.), several aspects of its biology are quite different from its more common relative. P. porrectella completed two generations per year and overwintered as an early-instar larva within apical buds of dame's rocket, Hesperis matronalis (L.). Four instars were observed in larvae reared in the laboratory. An average of 30 days was required for completion of one generation at 25 °C. This species does not seem to be an alternative host for parasites of the diamondback moth as only a single parasitic wasp, Itoplectis conquisitor (Say), was reared from 228 larvae collected in the field.

An intense forest fire destroyed a spruce (Picea spp.) stand in Agassiz Provincial Forest, Manitoba in May 1981. From 1 week following the fire, throughout the summer of 1981 and of 1982, carabid beetles were collected by pitfall trapping and standardized searches at weekly intervals. In all, 241 beetles of 24 species were collected. Agonum obsoletum Say and A. quadripunctatum De Geer were found; both species are known to be attracted to fires. A. quadripunctatum reproduced in the site in 1981 but there is no evidence that it did so in 1982. A. obsoletum was found in the study site only during the first 3 weeks after the fire. Evidence is presented to show that Harpalus laticeps LeConte is a characteristic species of forests after fire.

A simple age-specific energetics (calories or biomass) model for the growth and development, reproduction, respiration, ageing, and intrinsic survivorship as a function of temperature and per capita energy availability for pea aphid (Acyrthosiphon pisum (Harris)) is reported. The ratio of energy supply–demand is used to scale all of the rates in the model. The maximum demand for energy based upon current state values is used to drive the Frazer–Gilbert functional response model (i.e. food acquisition), which is a component of the metabolic pool model used to assimilate energy to growth, reproduction, respiration, and egestion. The extensive data sets on pea aphid energetics published by Randolph et al. (1975) were used to develop the model. As the model estimates reproduction (Mx) and survivorship (Lx) values, extensive published age-specific life-data sets on pea aphids are used to test it. The results suggest:

(1) the lower thermal threshold for development is raised and the upper threshold is lowered as food resources are decreased

(2) the temperature-dependent rate of development is slowed with decreasing energy resources

(3) the size of individuals and reproduction become smaller as temperature approaches the upper and lower thermal thresholds.A simple model for multitrophic level interactions incorporating the acquisition and assimilation functions is presented.

An energy-flow multitrophic-level model incorporating acquisition (functional response) and assimilation (metabolic pool model) functions and stochastic development is proposed and put into historical perspective. The model is general for each trophic level and for all subcomponents. Prey demand drives the functional response model, while food supply–demand determines all intrinsic rates in the model. The model is used to explore the theoretical properties of a multitrophic system comprising alfalfa, blue aphids, pea aphids, a host-specific parasitoid, and two predators (lady beetles, green lacewings). The model shows:

(1) the importance of the resource base on higher trophic level dynamics and vice versa

(2) the stability properties of different combinations of species

(3) the role of parasitoids and predators in population regulation in this system

(4) how food acquisition and respiration as functions of temperature and per capita resource interact to determine the rate of population growth

(5) that extreme caution must be used in extrapolating theoretical results to field situations.

The field population dynamics of pea aphid (Acyrthosiphon pisum) and blue alfalfa aphid (A. kondoi) in alfalfa (Medicago sativa), as influenced by weather, competitors (Egyptian alfalfa weevil = EAW, Hypera brunneipennis), predation from coccinellids (Hippodamia convergens) and harvesting practices, are examined with a stochastic multitrophic level simulation model. The model incorporates a demand-driven functional-response model to estimate prey consumption, and a metabolic pool model to determine the rates and priorities of food allocation to respiration, growth, reproduction, and egestion.

The model results compare favorably with field data, and are used to examine the effects of removal of each of the above factors on the dynamics of the aphids. The model shows that the observed density of EAW did not affect the aphid dynamics, but did reduce the standing crop of alfalfa. The predator H. convergens had a significant effect on the population dynamics of the aphids and the plant. Harvesting greatly affected the aphid population dynamics, as well as the dynamics of plant growth and reserve accumulation. However, high temperatures mediated through species-specific respiration costs and possibly a fungal pathogen were responsible for the observed dominance of blue aphid populations in the cool parts of the year and pea aphid populations during warmer parts of the year.

Native bee pollinators were collected and observed on cultivated blueberry, raspberry, and cranberry and on natural non-cultivated plants such as blackberry, buttercup, fireweed, thistle, and hairy cat's ear. Higher abundance and diversity of native bees were found on natural vegetation than on berry crops. Native bee populations on berry crops increased from 1981 to 1982, although diversity was similar. Native bees were not abundant enough to ensure adequate pollination of berry crops, and therefore, the use of managed honey bees is advisable. Pesticide impact, competition with managed honey bees, and habitat destruction have probably decreased native bee populations in agricultural areas of the Fraser Valley.

The use of a standard measure of native pollinator abundance, bees observed/min/m2, is recommended for future studies of this kind.

A small, undisturbed stream in central New Hampshire was treated for 1 min with a 10 ppm suspension of Bacillus thuringiensis var. israelensis (B.t.i.) to determine the effect on an outlet-breeding black fly population and associated nontarget aquatic insects. The black fly larval population was eliminated and susbsequent adult black fly biting activity reduced near the treatment site although weather conditions may also have contributed to an observed decrease in biting activity. Some Chironomidae were killed by B.t.i. but they were not abundant enough to adequately assess impact on their populations. Temporary increases in the drift of two Ephemeroptera and two Trichoptera species were observed following treatment. Increase in rate of drift was inversely related to increase in distance from the treatment point. Slight increases in observed drift of three Plecoptera species could not be attributed directly to the B.t.i. treatment. No direct mortality caused by B.t.i. was observed in any stream insects studied except black fly larvae and some Chironomidae.

Thuricide and Dipel, formulations of Bacillus thuringiensis (B.t.), were applied aerially against the spruce budworm, Choristoneura fumiferana (Clem.), in forest stands of balsam fir, Abies balsamea L. A dosage of 30 Billion International Units (BIU) of B.t./ha applied in 2.4 to 4.7 L of spray/ha was most effective. Application of 20 BIU/ha was marginally effective against a population of 12 to 36 larvae/45 cm of branch.

The seasonal distributions of Choristoneura occidentalis Freeman and C. retiniana (Walsingham) males attracted to pheromone sources overlapped considerably at two sites in south-central Oregon. Bimodality in the seasonal distributions of trapped males of both species was associated with a period of cool weather. The daily periods of female calling, and attraction of males to female-baited traps and to chemically baited traps overlapped greatly between the two species. However, these three aspects of C. occidentalis mating behavior began 1–2 h before those of C. retiniana. Under laboratory conditions, there was also considerable overlap in the calling periods of the two species; but again, C. occidentalis females initiated calling slightly earlier than did female C. retiniana. Females of both species continued to call many hours past the cessation of male attraction to pheromones in the field. Male attraction to pheromones occurred earlier on cool evenings than on warm evenings. Laboratory studies indicated a similar effect of temperature on timing of female calling. Little intraspecific variation in calling periodicity was observed among field-collected populations of each species. However, a C. occidentalis laboratory colony appeared to have partially lost its circadian rhythm of calling.

In western Canada, three wax-infesting moth species are serious pests of honey bee products, Vitula edmandsae serratilineella Ragonot, Achroia grisella (F.), and Plodia interpunctella (Hübner). The latter two species are found only in the Fraser Valley of British Columbia, while the driedfruit moth (sometimes called the bumble bee wax moth), V. edmandsae, is found throughout western Canada.

Three female-produced pheromone components of V. edmandsae were identified as (Z,E)-9,12-tetradecadien-1-ol, (Z)-9-tetradecen-1-ol, and (Z)-11-hexadecen-1-ol, and field tested. Pheromone baits were used in traps outdoors and in bee equipment storage facilities in the Fraser and Okanagan valleys of British Columbia. The peak indoor trapping period occurred during May in the Okanagan Valley, while catches in indoor traps in the Fraser Valley were negligible throughout the entire trapping period. Catches in outdoor traps peaked during July in both regions. Traps baited with (Z,E)-9,12-tetradecadien-1-ol, alone or in binary combination with (Z)-11-hexadecen-1-ol, were significantly more attractive to male V. edmandsae than all other treatments tested. At one apiary, cumulative moth catch from a trap line 1.0 m from hives was significantly greater than that from a trap line 4.5 m away. The results suggest that a pheromone-based monitoring and control program for V. edmandsae is feasible.

Effects of soil moisture, texture, and temperature on larval and pupal survival and development of the bean leaf beetle, Cerotoma trifurcata (Forster), were investigated in laboratory and greenhouse studies. In both cases, mortality rates were highest during the first instar, decreased during subsequent larval instars, then increased during the pupal stage. Under constant laboratory conditions, survival and adult weights were highest in wet and organic soils and lowest in dry and loamy sand soils. In wet and organic soils, developmental time was shorter than in other soils.

Although survival/plant in the greenhouse was greatest in sandy clay loam, survival/nodule was greatest in organic soil.

These studies, together with oviposition preference, egg survival, and larval movement experiments agree with field observations and provide some explanations for observed patterns of local and regional abundance of the bean leaf beetle in North Carolina.

Twig-feeding injuries by S. multistriatus in juvenile white (or American) elms occurred primarily (61%) in the upper 1/3 of the crowns. Preferred feeding sites were crotches formed by the previous year's and current year's twig growth (both spring and summer) and by leaf petioles from current year's twig growth (summer only). An index of twig feeding appeared to reflect S. multistriatus population trends and was closely correlated with Dutch elm disease rates in Syracuse, N.Y., from 1978 to 1982. Twig-feeding indices and catches on sticky traps baited with S. multistriatus pheromone were generally correlated, but disparate when competing natural pheromone sources were abundant. Twig sampling indicated that S. multistriatus populations and disease rates were reduced by mass-trapping and trap-tree techniques. The twig-sampling method presented appears to be useful in predicting Dutch elm disease rates and assessing the effectiveness of measures to control its beetle vector.

Populations of the citrus red mite, Panonychus citri (McGregor), reared on “rough lemon” seedlings (Citrus limon (L.) Burm.) in a greenhouse and treated with malathion or permethrin were significantly higher than those on untreated seedlings. Significant increases were demonstrated in age-specific fecundity (mx), mortality corrected mx (lx mx), and net reproductive rate (Ro) values for mites reared in the laboratory on leaves treated with malathion or permethrin when compared with those reared on untreated leaves. Mites reared on oxamyl-treated leaves exhibited significant reductions in age-specific survivorship (% lx), mx, lxmx, and Ro values compared with those reared on untreated leaves. The importance of reproductive stimulation in relation to other causes of pest resurgence is discussed.

A sequential egg-mass sample system for Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough (Lepidoptera: Lymantriidae), was designed, based on visual scanning of the lower branches of Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco. A branch was removed from each quadrant from the upper, middle and lower crown level, and from the lowest whorl of a total of 59 non-defoliated trees in 10 areas. No consistent trend in egg-mass density per branch could be found between crown levels and no level proved superior as a representative of the tree. Therefore, the lower whorl of branches was selected for survey purposes because of sampling efficiency. Sample stop lines were determined from egg-mass density and variability data collected on 55 sites and subsequent defoliation estimates were related to these densities. The system is designed as an early detection tool to be used only in non-defoliated stands at the incipient stage of an impending outbreak.

The male of the rare Bombus digressus (Milliron) is described based on new material from Costa Rica. Both male and worker castes display unusual combinations of structural characteristics and the unique male genitalia are considered to warrant the erection of a new monotypic subgenus, Digressobombus.