The biology of Pullus impexus (Muls.), a Coccinellid beetle predacious on Adelges piceae (Ratz.) in Switzerland, Germany and France, was studied during 1950–1952. The present work is a part of the research on the complex problem of factors in the control of the Balsam Woolly Aphid in Canada.

The morphology of both the larva and the adult has been studied. Some information has been provided on the probable distribution of the species.

P. impexus has only one generation a year. The eggs are deposited during the late summer or early autumn on infested trees and the larvae hatch in April. The larvae develop and adults appear in May. The adults of the new generation are to be found in June together with adults of the old generation. In the biology, particular attention has been directed to the diet of the insect in each of its stages, in order to establish the value of the species from the standpoint of biological control.

Two new species of Hymenopterous parasites were found in Switzerland and in Germany, Scymnophagus mesnili Ferr., a parasite of pupae, and Centistes scymni Ferr., a parasite of the imagines. The life history of these species has been briefly studied. A cephaline gregarine species was noted in the mesenteron of adults of P. impexus and a nematode in the abdominal cavity of a female. The two Hymenopterous species provide an important limiting factor in the increase of the population of P. impexus.

The common bed bug, Cimex lectularius (Hemiptera: Cimicidae), has recently re-emerged in increasing numbers, distribution and intensity of infestation in many countries. Current control relies on the application of residual pesticides; but, due to the development of insecticide resistance, there is a need for new tools and techniques. Semiochemicals (behaviour and physiology modifying chemicals) could be exploited for management of bed bugs. However, in order to identify semiochemicals that can be utilised in monitoring or control, a suitable olfactometer is needed that enables the study of the responses of bed bugs to volatile chemicals. Previous studies have used olfactometers that do not separate olfactory responses from responses to physical contact. In this study, a still-air olfactometer was used to measure behavioural responses to different bed bug-derived volatiles presented in an odour pot. Bed bugs were significantly more likely to visit the area above the odour pot first, and more frequently, in the presence of volatiles from bed bug-exposed paper but not in the presence of volatiles from conspecific bed bugs. Bed bug activity was found to be dependent on the presence of the volatiles from bed bug-exposed paper, the time during the scotophase and the sex of the insect being tested. The still-air olfactometer could be used to test putative semiochemicals, which would allow an understanding of their behavioural role in bed bug ecology. Ultimately, this could lead to the identification of new semiochemical tools for bed bug monitoring and control.

Information on the world distribution and host-plants of the Groundnut Bruchid, Caryedon gonagra (F.), has been summarised from the literature. As a result of misidentification of the species that attacks groundnuts and of differing views about its generic assignment, this information has been given under several different names. The records brought together here are believed all to represent C. gonagra, and in a number of cases this has been confirmed by examination of the material concerned by Mr. B. J. Southgate.

C. gonagra is widely distributed in the Old World tropics and sub-tropics, but it is absent from Australasia, and it has only a restricted distribution in the New World tropics. Almost all its host-plants belong to the Leguminosae, the principal one being the tamarind, Tamarindus indica, in the pod of which the beetle has been found to develop more quickly than in the groundnut.

Data on the life-history and habits, and on the duration of pre-adult development and adult life, are summarised from the literature.

Experiments are described to determine the optimum conditions for multiplication of C. gonagra, using groundnuts as food. When adult females were allowed to lay large numbers of eggs on shelled and unshelled nuts, only a small proportion of the resulting larvae completed their development, the number of adults that emerged averaging about 2·4 per kernel in shelled nuts and 3·2 in unshelled ones. The developmental period at 70 per cent. relative humidity was 42 days at 30°C. and 91–98 at 25°C.; the former figure is less than any recorded in the literature at higher or lower temperatures, and all subsequent experiments were therefore made at 30°C. and 70 per cent. relative humidity.

Adults confined for three weeks, starting when four days old, at the rate of 25 pairs on 160 g. of a mixture of broken and intact kernels gave rise to some 314 F1 adults; this total was virtually unchanged when 50 pairs were used, but lower densities, though giving rise to greater yields per parent adult, gave much lower yields per weight of food. Emergence of adults began six weeks after the date of egg-laying and reached its peak from one to three weeks later.

The yield from ten females on intact kernels was greater than from the same number on the mixture, but differed little whether the parent adults were left on for one week or three weeks, indicating that the majority of the eggs are laid in the first 11 days of adult life. The yield from unshelled nuts was nearly twice as great as that from shelled nuts, and also significantly larger than that from shelled nuts with ground shell added. Possible causes of this are discussed.

The sexes can be distinguished in the adult stage by differences in the terminal abdominal segments.

Bemisia tabaci biotype B is a significant pest of agriculture world-wide. It was first detected in Australia in 1994. Assessments of the potential of parasitoids already present in Australia to control this pest indicated that two species of Eretmocerus and 11 species of Encarsia were present, but they did not exert sufficient control with a combined average of 5.0±0.3% apparent parasitism of 4th instars. Further, only 25% of samples containing biotype B had parasitised individuals present. The surveys also identified that fewer B biotype were being parasitised compared with the Australian indigenous biotype. Overall, Er. mundus was the most abundant parasitoid prior to the introduction. Previous research indicated that Er. hayati offered the best prospects for Australia and, in October 2004, the first releases were made. Since then, levels of apparent parasitism have averaged 29.3±0.1% of 4th instars with only 24% of collections having no parasitism present. Eretmocerus hayati contributed 85% of the overall apparent parasitism. In addition, host plants of the whitefly with low or no parasitism prior to the release have had an order of magnitude increase in levels of parasitism. This study covers the establishment of the case to introduce Er. hayati and the post-release establishment period November 2004–March 2008.

Seasonal occurrence and abundance of redlegged earth mite, Halotydeus destructor (Tucker), was measured by weekly sampling in grazed annual pastures near Keysbrook (1990–1992) and Narrogin (1991–1992) in southwestern Australia. Mites were active for 27 weeks from the late autumn (May) to mid-spring (October), completing three generations at approximately 8 week intervals. The summer is spent as diapause eggs in the cadavers of adult female mites. In 1991 and 1992, active H. destructor was on average twice as abundant at Keysbrook (mean 11,300 mites/m2), as at Narrogin (mean 6400 mites/m2). Three times more eggs were laid at Keysbrook than Narrogin (mean 8500 and 2900 eggs/m2 respectively). Rainfall at Keysbrook was twice that at Narrogin, and temperatures were higher. We suggest that the rate of oviposition was less at Narrogin, probably because of resource limitation. The mature adult sex ratio was female biased, but was lower at Keysbrook (0.669) than at Narrogin (0.813). Neozygites acaridis, a fungal disease, was detected in less than 4% of the population, mainly in adult mites in late spring. Rainfall and temperatures were lower in the spring of 1992 than 1991 at both sites. Pasture was grazed considerably shorter in the spring of 1992, and numbers of H. destructor were lower, but numbers of eggs laid in the two years were similar. We suggest that active mite mortality was greater in spring of 1992, probably due to lower relative humidity. There were fewer adult mites in spring, and fewer diapausing eggs in summer at both sites in 1992 (36,600 diapause eggs/m2) than in 1991 (148,000 diapause eggs/m2). It is proposed that controlling mites in spring should lead to lower numbers of diapause eggs in summer and of mites emerging in autumn.

A new type of olfactometer was designed to study the responses of mosquitos to various stimuli. Hosts could be displayed downwind as well as upwind from the mosquitos, and two hosts could be displayed simultaneously, one upwind from the other. Responses to radiations, if any, and to odours could be measured.

Mosquitos were not attracted downwind to an arm displayed within 61 cm., even when they were stimulated by CO2 (under an incident illumination of about 10 foot-candles). About half the mosquitos showed a positive anemotactic response (i.e., they left the end downwind compartment in which they were released) in a current of room air, which undoubtedly contained human emanations. Only 15 per cent, responded to filtered air. Carbon dioxide caused no increase in response to filtered air but increased the number responding to room air (76 per cent, left the end down-wind compartment). Equal numbers of mosquitos responded to an arm displayed upwind in room air and in filtered air, i.e., about 83 per cent, left the end compartment. Carbon dioxide caused no increase in the number of mosquitos responding to an arm but increased the number responding to attenuated emanations from an arm. A repellent (deet) eliminated most of the response to an arm; the addition of carbon dioxide increased upwind flight to the treated arm, but many of the mosquitos flew past it. Carbon dioxide therefore appears to have a synergistic action with arm odours in the attraction of females of Aedes aegypti (L.). However, this conclusion does not exclude other behavioural effects of carbon dioxide demonstrated by other investigators.

Eesponses to arms in this new type of olfactometer were nearly identical to those obtained in another type previously used in a large-scale study. The testing confirmed earlier reports that mosquitos do not fly far in the same direction as wind-current and that host location was not possible through positive anemotaxis in the absence of light. Mosquitos were not attracted to a source of infra-red radiation.

The new direct method of comparing the attractiveness of different subjects demonstrated that mosquitos would leave the vicinity of one arm and migrate further upwind to another that was more attractive. Water and acetone rinses of human arms reduced attraction; acetone appeared to be a better solvent for the attractant substance than water.

The continuous automatic monitoring of the aerial density, biomass and relative diversity of high-flying insect faunas has been made practicable by a new, vertical-looking radar. This inexpensive radar system, with its novel signal analysis capability, represents a major advance over earlier vertical-beam radars because it provides estimates of the body mass of individual overflying insects, as well as measurements of their direction and speed of movement. This paper summarizes data collected over a three-month period by the new radar in the height range from 150 m to c.1 km, over agricultural land in Worcestershire, England. The day-to-day variation in the numbers of insects and their altitudinal and diurnal patterns of flight activity are presented. Examples are also given of distributions of mass, displacement speed and direction, and orientation direction. The potential of the new radar for various research and operational monitoring tasks is briefly discussed.

The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin®WG™, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 μg ml−1, respectively. Bt–azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray–azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

The effect of ivermectin treatment of cattle on the rate of dung beetle colonization of cow pats was assessed by pitfall trapping in Denmark, Tanzania and Zimbabwe. Ivermectin was injected subcutaneously into heifers at the recommended dose of 0.2 mg/kg body weight, and dung to be used as bait in pitfalls was collected at intervals after treatment. In one experiment in Denmark, species of the scarab beetle Aphodius and the hydrophilids Sphaeridium and Cercyon, preferred control dung from untreated cattle; no preference was found in two other experiments, involving some of the same species. In the Tanzanian trials, the overall tendency for scarabaeid beetles was to prefer control dung. In Zimbabwe, two scarabaeid species (Euoniticellus intermedius (Reiche) and Liatongus militaris (Castelnau), both belonging to Oniticellini) were particularly attracted to dung from treated cattle; two other scarabaeids showed no preference. It is concluded: 1. That ivermectin therapy can affect the rate of dung colonization by attracting or repelling beetles. 2. That the responses are probably not caused by ivermectin per se, but by some side effect, the nature of which is obscure and unpredictable with our present knowledge.

In laboratory colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich), discs cut from young leaves of several plant species were picked up more readily than those from old leaves. Pith sections impregnated with whole extracts of young leaves were consistently picked up in preference to others with extracts of old leaves, and non-lipid extracts were consistently preferred to extracts containing lipids. Arrestive properties were confined to the non-lipid extracts, and inhibitory properties were mainly found in the lipids, but removal of lipids from the whole extracts did not necessarily make them more arrestive. In most cases, dewaxing of leaves with chloroform made them more acceptable, and heating and freezing of leaves had a similar effect. Leaf waxes showed inhibitory properties. Wax extract of young leaves was often preferred to that of old leaves, and differences in preferences were observed for wax extracts from different plant species. The implications of these findings for the relationship between leaf-cutting ants and the vegetation that they cut are discussed.

Infestations of Eldana saccharina Walker in South Africa are higher in intensively-grown than in peasant-grown sugarcane, and are worse in water-stressed plants. Although field trials showed negligible increases in the incidence of the pest with applied nitrogen, the degree in which the degree of water stress could not be controlled. Pot-plant trials, in which the degree of water stress was controlled as well as the amount of fertilizer, showed that the combination of nitrogen with stress resulted in increased survival of larvae and greatly increased biomass with shortened development times. Adults did not appear to choose stressed or fertilized plants in preference to normal or unfertilized ones. In every case, whether in the field or in insectary trials, increased infestation levels were associated with increased stalk total nitrogen. Amino acid determinations showed that the balance of individual acids did not appear to alter but that the balance of individual acids did not appear to alter but that glyphosate ripener had a similar effect to water stress, increasing all amino acids together. Infestations in older cane were disproportionately higher than in younger cane, weight for weight, despite reduced levels of stalk nitrogen. This anomaly may be due to the presence of phenolic compounds in younger cane, or in cane tops. Levels of nitrogen are much higher in the feeding sites of the insect in natural host-plants than in cane stalks, and the fecundity of feral moths natural hosts appeared to be higher than that of moths from sugarcane. The insect appears to have invaded sugarcane when stalk nitrogen levels reached sufficiently high levels for its survival as a result of intensive cultivation.

The development of the khapra beetle, Trogoderma granarium Everts, and the cycle of movement of insects between the food and hiding places has been studied at 30°C. The results have been correlated with observations at maltings, its chief habitat in Britain.

In populations at 30°C., many larvae delay pupation and enter diapause, the remainder spending most of their time in the food and completing development quickly. The diapause larvae leave the food in the fourth and in later instars in search of hiding places. Disturbing the food stimulates the larvae to leave it a little earlier. Larvae resting in diapause moult occasionally, and at long and irregular intervals they emerge, presumably to replenish their food reserves by feeding, after which some pupate and the rest hide again.

The hidden diapause larvae can persist for a very long time; in cultures, 16 per cent, remained after four years. Apparently, as the food stored in the fat-body is depleted, they become readier to emerge from the crevices to feed. Replacing stale food by new food causes some larvae to emerge and the effect of disturbing the larvae is variable. After feeding, some of these larvae complete development and the resulting adults breed, presumably producing both quick developing and diapause larvae among their offspring.

When denied a hiding place, the diapause larvae remain inactive in the food without increasing their rate of pupation. However, they feed more, producing heavier beetles, an effect also obtained by regularly providing fresh food.

It is concluded that when a malt store is loaded, some diapause larvae remain in the fabric of the store and others emerge and feed; after feeding, some larvae re-enter crevices and others complete development and breed; the offspring contain some diapause larvae, which accumulate in the crevices and on the walls just below the malt surface; after the malt is unloaded, diapause larvae may persist in empty stores for a number of years, because they can restore their food reserves by occasionally eating grain residues.

The oriental army worm Mythimna separata (Lepidoptera: Noctuidae) is a migratory pest in Eastern Asia and China. Seasonal high temperatures in Southern China and low temperatures in Northern China are pressures favouring the annual migration of this species, while cold tolerance determines the northern limit of its overwintering range. A number of physiological stress responses occur in insects as a result of variations in temperature. One reaction to thermal stress is the generation of reactive oxygen species (ROS), which can be harmful by causing oxidative damage. The time-related effects (durations of 1, 4 and 7 h) of thermal stress treatments of M. separata at comparatively low (5, 10, 15 and 20°C) and high (30, 35, 40 and 45°C) temperatures on the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and glutathione S-transferases (GSTs), and total antioxidant capacity (T-AOC) were determined. Thermal stress resulted in significant elevation of the activities of SOD, CAT and GSTs, indicating that these enzymes contribute to defence mechanisms counteracting oxidative damage caused by an increase in ROS. However, at high-temperatures, POX and T-AOC were also found to contribute to scavenging ROS. Our results also indicate that extreme temperatures lead to elevated ROS production in M. separata. The present study confirms that thermal stress can be responsible for oxidative damage. To overcome such stress, antioxidant enzymes play key roles in diminishing oxidative damage in M. separata.

The results presented in this paper refer to a host survey, lasting approximately three and a half years (February 2003–July 2006), undertaken in the Vale do Rio Doce Natural Reserve, a remnant area of the highly endangered Atlantic Rain Forest located in Linhares County, State of Espírito Santo, Brazil. A total of 330 fruit samples were collected from native plants, representing 248 species and 51 plant families. Myrtaceae was the most diverse family with 54 sampled species. Twenty-eight plant species, from ten families, are hosts of ten Anastrepha species and of Ceratitis capitata (Wiedemann). Among 33 associations between host plants and fruit flies, 20 constitute new records, including the records of host plants for A. fumipennis Lima and A. nascimentoi Zucchi. The findings were discussed in the light of their implications for rain forest conservation efforts and the study of evolutionary relationships between fruit flies and their hosts.

Operated in sheltered woodland, the samples obtained by Rothamsted tungsten-filament and Robinson mercury-vapour traps are best described by a spatial model different from that used in a site exposed to wind. Differences between the proportions of Noctuidae and Geometridae were accountable to differences in height of flight. The Rothamsted traps gave more consistent samples than the Robinson traps and averaged about onequarter the number of moths.

Diamondback moth or DBM is the major pest of Brassica vegetable production worldwide. Control has relied on insecticides, and DBM resistance to these compounds has evolved rapidly. We review and summarize data on DBM population dynamics across a large latitudinal gradient from southwest to northeast China: DBM is, on average, more common in southern locations than in northern locations. The species' phenology is consistent: in southern and central locations there is a decline during hot summer months, while in the north, the species can only exist in the summer following migrations from the south. A cohort-based discrete-time model, driven by daily maximum and minimum temperatures and rainfall, which was built using the DYMEX modelling software, captures the age-structured population dynamics of DBM at representative locations, with year round cropping and threshold-based insecticide applications. The scale of the simulated pest problem varies with cropping practices. Local production breaks and strict post-harvest crop hygiene are associated with lower DBM populations. Biological control appears to improve the management of DBM. Of the management strategies explored, non-threshold based applications of insecticides with reduced spray efficacy (due to poor application or resistance) appear the least effective. The model simulates the phenology and abundance patterns in the population dynamics across the climatic gradient in China reasonably well. With planned improvements, and backed by a system of field sampling and weather inputs, it should serve well as a platform for a local pest forecast system, spanning the range of DBM in China, and perhaps elsewhere.

For most plant species, tolerance to many types of herbivory increases as plants age, but the applicability of this pattern to root herbivory has not been tested. Injury to roots of rice plants by larvae of the rice water weevil, Lissorhoptrus oryzophilus Kuschel, causes severe reductions in yields in the United States. It is generally thought that young rice plants, because their root systems are smaller, are less tolerant than older plants of root feeding by L. oryzophilus. Field experiments were conducted to test this hypothesis. Plots of rice (4.7 to 6.5 m2) were established and subjected to natural infestations of L. oryzophilus larvae. A soil insecticide was applied to plots at different times during the tillering phase of rice in order to manipulate the timing of weevil infestation. The impact of these treatments (timings of insecticide applications) was assessed by comparing relationships between yield loss and larval pressure for each treatment using analysis of covariance. Yield losses ranged from 13% to over 40% in plots not treated with insecticide. Patterns of yield losses from plots treated with insecticide at different times were best explained by the hypothesis that yield loss is determined both by the age of plants infested and by the size of larvae infesting plants. Young plants appear to be less tolerant than older plants, and feeding by large larvae appears to be more deleterious than feeding by smaller larvae. Management practices that delay infestation of rice by L. oryzophilus until plants are older may be an important component of management programmes for this pest.

A study was undertaken to identify the major larval habitats of the Anopheles gambiae (Giles) complex in rural Gambia. Mosquito larvae and pupae were sampled along transects and in specific habitats in the central region of the country during the rainy seasons of 1996 and 1997. The sampling showed that the major breeding sites were located on the flooded alluvial soils bordering the river. The largest numbers of larvae were found during September, one month after the peak rains. Polymerase chain reaction analysis of specimens showed that Anopheles melas (Theobald) was the dominant species in the flooded areas (81.5%), followed by A. gambiae sensu stricto (Giles) (18.0%) and A.arabiensis (Patton) (0.5%). By sampling in specific habitats it was evident that A.arabiensis was mainly breeding in rain-fed rice fields along the edge of the alluvial soils. Anophelesmelas and A.gambiae s.s. often coexisted but whereas A. melas were found in water with a salinity of up to 72% sea water (25.2 g NaCl l−1), A.gambiae s.s. only occurred in water with up to 30% sea water (10.5 g NaCl l−1). Anophelesmelas larvae were found in association with plant communities dominated by sedges and grasses (Eleocharis sp., Paspalum sp., Sporobolus sp.) and sea-purslane Sesuviumportulacastrum (L.) and the presence of cattle hoof prints, whereas A.gambiae s.s. larvae mainly occurred in association with Paspalum sp. and Eleocharis sp. The study showed that even during the peak rainy season, breeding of the A.gambiae complex is almost entirely restricted to the extensive alluvial areas along the river.

Quantitative real-time PCR (qRT-PCR) has been used extensively to analyze gene expression and decipher gene function. To obtain the optimal and stable normalization factors for qRT-PCR, selection and validation of reference genes should be conducted in diverse conditions. In insects, more and more studies confirmed the necessity and importance of reference gene selection. In this study, eight traditionally used reference genes in Galeruca daurica (Joannis) were assessed, using qRT-PCR, for suitability as normalization genes under different experimental conditions using four statistical programs: geNorm, Normfinder, BestKeeper and the comparative ΔCt method. The genes were ranked from the most stable to the least stable using RefFinder. The optimal suite of recommended reference genes was as follows: succinate dehydrogenase (SDHA) and tubulin-alpha (TUB-α) for temperature-treated larvae; ribosomal protein L32, SDHA and glutathione S-transferase were best for all developmental stages; ACT and TUB-α for male and female adults; SDHA and TUB-α were relatively stable and expressed in different tissues, both diapause and non-diapause adults. Reference gene evaluation was validated using expression of two target genes: the P450 CYP6 gene and the heat shock protein gene Hsp70. These results confirm the importance of custom reference gene selection when studies are conducted under diverse experimental conditions. A standardized qRT-PCR analysis procedure for gene functional studies is provided that could be useful in studies on other insect species.

Six species of insects and a rust fungus have been successfully established for biocontrol of the weed Parthenium hysterophorus L. in Queensland, Australia. Effectiveness of biocontrol insects was evaluated at two properties in Queensland during 1996–97 based on an exclusion experiment using insecticides. Parthenium-infested plots with and without biocontrol insects were sampled at monthly intervals and the impact of biocontrol insects on parthenium at individual plant and whole population levels monitored. Biocontrol insects were more effective at Mt Panorama (central Queensland) than at Plain Creek (north Queensland). At Mt Panorama, the leaf-feeding beetle Zygogramma bicolorata Pallister caused 96% defoliation and the stem-galling moth Epiblema strenuana Walker affected 100% of the plants, resulting in reductions of 90% in weed density, 40% in plant height, and 82% in flower production. Exclusion of biocontrol insects resulted in a 52% increase in seedling emergence and a seven-fold increase in the soil seed bank in the following season. At Plain Creek, E. strenuana was the only prominent agent. It affected 92% of the plants and prevented 32% of plants from producing any flowers, reduced plant height by 40% and flower production by 49%, but did not reduce the plant biomass, weed density or soil seed bank. However, exclusion of biocontrol insects resulted in an eight-fold increase in the soil seed bank in the following season.