An absolute requirement for sugar could not be shown but laboratory rearing experiments using artificial diets have demonstrated a definite increase in weight of adult spruce budworm (Choristoneura fumiferana (Clem.) Freeman) with increasing dietary levels of certain sugars. Males exhibit a threshold of 0.9% soluble sugars above which higher sugar levels produce no further increases in size. Females respond with an increase in size up to 4.0%, the highest level tested. Generally, faster development rates accompany greater mature weights on diets with higher nutrient levels.

Maltose, raffinose, glucose, sorbitol, sucrose, and fructose are all good sugar sources. Galactose and trehalose are only slightly inferior. Lactose, ribose, melibiose, xylose, mannose, arabinose, and melezitose in the diet are little different from the sugarless control. Sorbose is somewhat inhibitory.

Results of transfer experiments confirm the importance of sugar particularly during late larval development. They also indicate that a high protein diet during early instars has a significant effect on development rates. These results suggest that departure from the normal synchrony of development in the insect and its host can affect both rate of development and mature size of the insect.

Tarsi of male Colorado potato beetles adhere to glass and plastic surfaces limiting locomotion greatly. This is not observed with females. Scoop-like tarsal hairs present only in males are responsible for the adherence. The effect of this morphological difference on toxicological or behavioral research conducted in glass or plastic cages is discussed.

Animals are capable of multiplying their numbers by some form of reproduction; but they are hindered by natural means from multiplying to the point of committing collective suicide by exhausting the resources of this planet. Animals are also subject to having their numbers decreased; but, likewise, their decrease to extinction is hindered by natural means. The question of these natural means of limiting increase and decrease of numbers is a fundamental problem of Ecology: the problem of the mechanism of natural control of populations. The solution of this problem has, of course, great practical interest because man suffers from some animals being too few (beneficial species) and others too numerous (pests).

The photoperiodic reaction in North American codling moth populations displayed clinal-type variation similar to populations in Europe. A latitudinal shift of 10° to the north corresponded to an increase of 1.25 h in the critical photoperiod. Intrapopulation variance in diapause response appeared to be similar in populations of different origin. The critical photoperiod was not constant for a geographic population but varied between years probably due to the modifying effect of prediapause temperatures. In Michigan and other areas in the northeastern United States with similar climate the codling moth is essentially bivoltine with considerable yearly variability in second generation emergence. A graphic model is presented which gives an estimate of voltinism and the proportion of diapausing first-generation larvae based on the seasonal heat unit total at the time of diapause initiation. From an analysis of original data and historical phenological records an algorithm was developed which describes the relationship between effective temperatures and the variance of second generation emergence and which can predict population curves for climatically different years. Use of this predictive method in conjunction with monitoring information provided by a pheromone trap is discussed.

Cortical blister and wound reaction resin vapors from Abies grandis, and some of their monoterpene fractions, were quantitatively bioassayed for attractiveness and repellency to the fir engraver beetle, Scolytus ventralis. All were found to be repellent.

Quantitative differences between liquid resins and vapors were examined. Wound reaction resin vapors contained higher percentages of the more repellent monoterpenes than cortical blister resin vapors. It is hypothesized that α-pinene is the most important monoterpene in the insects’ perception of a resistant host.

Loblolly pine trees struck by lightning offer a favorable attack and brood environment for the southern pine and Ips beetles. In central Louisiana lightning strikes reduced oleoresin exudation pressure, oleoresin flow, and relative water content of inner-bark tissue and resulted in a decrease in sucrose and an increase in reducing-sugar content of inner bark. Interspecific competition was much greater in struck trees than nonstruck trees. Among struck trees, those with highest carbohydrate levels produced the most numerous broods of the southern pine beetle.

Continuous trapping on the bark surface of Dendroctonus brevicomis LeConte infested trees in the central Sierra Nevada mountains was undertaken with the objective of determining the spatial and temporal arrival patterns of the natural enemies and other insect associates of the western pine beetle. Over 100 species of D. brevicomis associates were collected and patterns of arrival were described for many of these. The main bark beetle predators were trapped during D. brevicomis mass arrival and shortly thereafter. Enoclerus lecontei, Temnochila chlorodia, and Aulonium longum, all predaceous beetles on D. brevicomis adults and larvae, were among the first species to arrive, as was Medetera aldrichii (Diptera), a larval predator. The bark beetle parasites Roptrocerus xylophagorum and Dinotiscus (=Cecidostiba) burkei (Hymenoptera) were well synchronized with the beetles’ life cycle as they arrived late in the beetles’ larval stages when suitable hosts were available.

Approximately twice as many associates were trapped in the first (spring) beetle generation as in the second (fall). Differences between species with regard to height distribution were common, and these often varied with seasonal beetle generation.

Calculations of changes in species diversity through time, of the associate complex trapped at the bark surface, were made for both the first and second beetle generation. Linear correlation analysis indicated a highly significant increase in species diversity occurred from the time of the beetles’ mass arrival until brood emergence. This increase may correspond to an increase in diversity of the structure of the subcortical community, as more insect species arrived and progressively modified the habitat of the newly killed tree.

Investigations in 1959 (Dyer and Kinghorn, 1961) revealed a large overwintering population of the ambrosia beetle, Trypodendron lineatum (Oliv.), in a level accessible stand of timber. It was decided to use this location for field studies on attack behaviour of this insect, with three general objectives in mind: 1) direct observation of beetles as they searched for and found suitable log material; 2) experimental verification by means of various ‘hidden log’ situations, with controls, of the importance of smell in the beetles' search, and 3) observation and measurement of differences in attractiveness between logs during the flight period.

Trichogramma minutum Riley entered diapause, in the prepupal stage, in eggs of Lambdina fiscellaria fiscellaria Guenée held at 15°C, 12L:12D, but failed to do so in eggs of Ephestia kuehniella (Zeller), Sitotroga cerealella (Olivier), or Choristoneura fumiferana (Clemens) held under these conditions. The parasitoids emerged without diapause from eggs of all host species held at 25°C, 16L:8D, indicating a role of temperature or photoperiod, or both, in the diapause of the parasitoids in eggs of L. fiscellaria held at 15°C, 12L:12D. Percentage emergence of parasitoids from eggs of L. fiscellaria was virtually the same (>80%) after passing the winter outdoors or after approximately 3 months at 2 °C in the laboratory as it was when reared indoors in this host at 25°C, 16L:8D. Emergence of T. minutum was very poor (<20%) after long-term, low-temperature storage in eggs of C. fumiferana, E. kuehniella, or S. cerealella. Apparently, T. minutum must parasitize diapause host eggs in order to enter diapause, and good survival after long-term low-temperature storage is possible only when T. minutum is in diapause. Trichogramma minutum will enter diapause in L. fiscellaria after 14 days at 15°C, 12L:12D, but the parasitoids need a period of storage at 2°C, 0L:24D for a high percentage of emergence to happen. Over 50% emergence was recorded for T. minutum, held for 300 days in eggs of L. fiscellaria.

Drawing retrospectively and collectively on results of a single individual and his associates covering some 22 years of field and laboratory studies, the authors present three documented case histories of technically complete biological control. They use these examples to illustrate the potential for greater use of this method of pest control, and they discuss the theory of biological control as related to whether or not introductions of a complex of enemy species will inherently lead to competitive interference and a lesser degree of control than if only the "best" species were introduced. They conclude that the three case histories are a refutation of this thesis, as are certain theoretical considerations, and the net results from all biological control programs on a worldwide basis.The authors also point to weaknesses in the use of currently available methods for quantitatively rating or appraising the control and regulating power of density-dependent factors that act with a lag (entomophagous parasites and predators), and emphasize chat regression and modelling methods should be used in conjunction with "check-methods" or other experimental means.

In 1996, damage symptoms typical of the swede midge, Contarinia nasturtii (Keiffer), were observed on broccoli, Brassica oleracea L. var. italica (Brassicaceae), crops east of Toronto, Ontario. Early attempts to identify an associated insect larva were unsuccessful, and damage symptoms became mistakenly attributed to nutrient deficiencies (T Clarke, personal communication). Between 1996 and 1999, damaged plants were seen by growers regularly, and resulted in up to 85% loss of marketable yield (T Clarke, personal communication). In June 2000, we initiated investigations at two sites 12 km apart to determine the causal organism of this damage. Both sites were located at farms where cole crops are primarily -gown and from where the first damage reports originated.

In July, 1956, studies on mortality factors affecting abundance of immature stages of the eye-spotted bud moth, Spilonota ocellana (D. & S.), and the pistol casebearer, Coleophora serratella (L.), on apple were initiated in permanent orchard plots at Rougemont, Que. The object was to prepare life tables (Morris and Miller, 1954) for successive generations of each species through the rise and fall of a local epidemic. In preparing such tables, sound sampling techniques are necessary (Morris, 1955). This is a report on variation in samples, and in some mortality factors, of immature stages of the two species for the years 1956 to 1959, and on sampling recommendations.

The life history of the Sitka spruce weevil, Pissodes sitchensis Hopk., is described. Adults overwinter in duff at the base of trees and emerge in April or early May. Oviposition begins in late April on leaders. The larvae hatch and mine downward, eventually girdling and killing the leader. Larvae pupate in chip cocoons under the bark. Newly developed adults start emerging in August and, prior to hibernation, feed on leaders of young trees. Adults have been observed in the field as late as December.

Predators caused heavy mortality but the weevil population maintained itself and increased in some years. Parasitism was light. Natural control factors reduced the population level but were incapable of controlling a population. Satisfactory control was obtained by applying DDT and phosphamidon to leaders with a hand-sprayer early in the spring, but repeated applications would be necessary to protect a plantation through the critical years.

Damage to Sitka spruce regeneration and plantations in British Columbia is severe. At present, protection of Sitka spruce plantations would require considerable expense.

Four species of Cruciferae [canola species Brassica rapa L. and Brassica napus L., and mustard species Brassica juncea (L.) and Sinapis alba L.], and various cultivars of each species, were evaluated for susceptibilities to infestation by Delia spp. (Diptera: Anthomyiidae) under field conditions in central Alberta, Canada. Susceptibility was measured throughout the season by recording numbers of eggs of Delia spp. laid on or near individual plants, and at the end of the season by a semi-quantitative determination of injury inflicted by larvae on taproots. Differences in susceptibility occurred among and within canola and mustard species. Plants of B. rapa were most susceptible to Delia spp.; both mean eggs per plant and mean damage ratings per plant on B. rapa significantly exceeded those of all other species studied. Intermediate susceptibility was observed for plants of B. napus and B. juncea; plants of S. alba were least susceptible. In general, differences in susceptibility were greater among species than among cultivars within species. Root damage generally correlated with oviposition among and within species, suggesting that the mechanism of resistance by cruciferous species to infestation by Delia spp. is antixenosis or nonpreference. Results of this study indicate that canola growers in regions infested annually by high population densities of Delia spp. should seed B. napus or B. juncea rather than B. rapa. However, if a short growing season necessitates seeding B. rapa, then growers should select the more resistant cultivars of this species.

Fourteen new records of introduced leafhoppers are added to the 157 leafhoppers previously recorded as occurring in both the Old and New worlds. Of these, 62 were erroneously recorded previously although 12 of the European species subsequently have been found in North America. Two North American species have been introduced into Europe, and one European species has been found in South America; North America has received 61 species from Europe, 3 from Asia, and 1 from Africa. One pan-tropical species is probably a recent introduction into the Caribbean from the Old World. There are 30 transboreal leafhoppers, 5 transarctic species inhabiting the tundra and alpine meadows, and 9 inhabiting temperate regions of both Eurasia and North America.

The Aster leafhopper (Macrosteles quadrilineatus Forbes) is removed from synonymy with the transboreal sedge-feeding M. fascifrons (Stål) and 25 other confused species are distinguished in the genera Aphrodes, Euscelis, Evacanthus, Limotettix, Macrosteles, and Typhlocyba. These include 11 new species: Evacanthus bellaustralis, E. chlamidatus, E. grandipes, E. lacunar, E. nigramericanus, E. ustanucha, Macrosteles lagus, M. severini, M. tesselatus, M. vilbastei, and Typhlocyba frigida, all from North America, Balclutha punctata confluens Rey and Limotettix striola ferganensis Dubovsky are elevated to species status. One new generic synonymy, 23 new specific synonymies, and 3 new combinations are created.

Larvae of Pseudaletia unipuncta (Haw.), reared on corn foliage, were found to vary in the rate they were able to feed, grow, and attain maturity. Mortality varied inversely with the rate of food intake. In the fifth and sixth instars, there was a direct linear relationship between rate of food intake and daily growth, and rate of food intake and daily development. A variance of 78 to 96% in final weights of the two stages was explained by the combined effect of initial weights of larvae, food supply, duration of feeding, and food ingested. Fecundity increased with the rate of food intake of the larvae.When P. unipuncta feeds at a high rate, it is able to accelerate development, increase growth, and maintain a high reproductive potential. When the rate of food intake is low, development, growth, and fecundity are reduced for the sake of survival.

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), is a destructive insect pest in western Nearctic conifer forests. Currently, British Columbia, Canada, is experiencing the largest recorded outbreak of this insect, including areas that historically have had low climatic suitability for it. We analyzed 26 constitutive resin terpenes in phloem samples from British Columbia lodgepole pine (Pinus contorta) populations to test for differential resistance to mountain pine beetle attack, based upon the likelihood of previous exposure to mountain pine beetle. We assessed sampled trees for number of mountain pine beetle attacks, number of pupal chambers, and tree survival the following spring. Significant differences were found when levels of certain terpenes in lodgepole pine populations that had likely experienced substantial mountain pine beetle infestations in the past were compared with those in populations that likely had not experienced large outbreaks of mountain pine beetle. Although we expected southern pine populations to contain more total terpenes than northern populations, owing to higher historical exposure to the beetle, the converse was found. Northern populations generally had higher levels of constitutive terpenes and beetle attack than southern populations. Because several terpenes are kairomones to the mountain pine beetle and also serve as precursors for the synthesis of pheromones, the lower levels of terpenes expressed by lodgepole pines from the historical range of the mountain pine beetle may render them less chemically perceptible to foraging beetles.

Adults of most species of insect parasites spend much time finding objects that influence their individual and collective well-being. The object found at any time is usually correlated with the physiological state of the parasite and with extrinsic factors existing at that time. From the standpoint of the species' economy, the most important objects to be discovered are hosts on which fertile parasite progeny can mature. Whether hosts are found and parasitized is influenced, to varying degrees with different parasite species, by whether the female has already found, or been found by, a male of the same species, and by whether she has already located food other than that provided by hosts. The present study is of factors that affect host finding by females of a pteromalid, Nasonia vitripennis (Walk.).

Many factors influence the host preferences of entomophagous insects and have an important role in determining the fate of parasites in the field. Some of the factors influence the ability of parasites to locate their hosts. Others determine the suitability of the host as a medium for larval development (7, 15, 18, 26, 27, 31). These factors together determine the range of hosts attacked and control the degree to which nonpreferred hosts are selected.

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a non-native, wood-boring beetle that has caused widespread mortality of ash (Fraxinus Linnaeus (Oleaceae)) in eastern North America. During 2004–2007, we determined whether forest community composition and structure of black (F. nigra Marshall), green (F. pennsylvanica Marshall), and white (F. americana Linnaeus) ash stands influenced their susceptibility to EAB invasion in southeast Michigan, United States of America. There was no relationship between EAB-induced ash decline or percentage mortality and any measure of community composition (tree species diversity, stand/ash density, total basal area, or relative dominance of ash). There was also no relationship between measures of EAB impact (density of EAB signs, ash decline rating, percentage ash mortality, or percentage infested ash) and forest attributes (ash/total stand density, basal area, ash importance, or stand diversity). Decline and mortality of black ash advanced more rapidly than that of white and green ash. Percentage mortality of ash increased from 51% to 93% during 2004–2007. Distance from the epicentre of the invasion was negatively correlated with ash mortality, but this relationship dissipated over time. Stand composition data suggests that ash will be replaced by Quercus Linnaeus (Fagaceae), Acer Linnaeus (Sapindaceae), and Tilia Linnaeus (Malvaceae); such vegetation changes will irreversibly alter the structure and function of these forests.