Cydia pomonella is a serious invasive insect pest in China, and has caused severe damage to the production of apple and pear in its invaded areas. This species is distributing in the northwest and northeast of China, but no occurrence of it has been recorded in the large areas (about 3000–5000 km away) between the invaded northwestern and northeastern regions despite continuous monitoring. As yet the genetic diversity and invasion origin of the C. pomonella populations in Northwestern and Northeastern China is obscure. In this study, we investigate the genetic diversity of 14 populations of C. pomonella sampled throughout the main distribution regions in Northwestern (Xinjiang and Gansu Provinces) and Northeastern (Heilongjiang Province) China and compared them with nine populations from Europe and other continents using the mitochondrial COI, COII and Cytb genes. Both the populations from Northeastern and Northwestern China shared some haplotypes with populations from other countries. Haplotypes of the three mitochondrial genes had a different distribution in Northeastern and Northwestern China. The northeastern populations had more private haplotypes than the northwestern populations. A large number of the individuals from northwestern populations shared a few haplotypes of each of the three genes. The haplotype numbers and haplotype diversities of the northeastern populations were similar to those of field populations in other countries, but were higher than those of the northwestern populations. Populations from the Northwestern China showed similar haplotype number and haplotype diversity. We conclude that the population genetic background of C. pomonella populations in Northeastern and Northwestern China varies due to different invasion sources and that this should be considered before the application of new pest control tactics.

The liquid excrement of many Homoptera, which often accumulates as honeydew, can be harmful to the insects that produce it. Disposal of excrement to avoid or reduce its harmful effect is therefore important. The methods of disposing of excrement in Coccidae are described. These insects have an anal apparatus for propulsion of excrement away from the body. The musculature of the rectum is not involved in this act. Attendance by ants modifies excretory behaviour in Coccidae, much as it does in Aphididae.

To study the effects of plant density on populations of the cabbage root fly (Erioischia brassicae (Bch.) ) and the cabbage stem weevil (Ceutorhynchus quadridens (Panz.)), cauliflowers were planted in 24 concentric circles to achieve spacings of 10–90 cm at 22 plant densities (1·5–83/m2). Some plants were treated with a root drench of chlorfenvinphos. Each week female cabbage root flies laid approximately three times as many eggs per individual plant at the lowest than at the highest plant densities tested. This was equivalent to approximately 350 and 5000 eggs/m2, respectively. The numbers of cabbage root fly pupae produced ranged from 11/m2 at the lowest to 210/m2 at the highest plant density. In the absence of an insecticide, increasing the plant density considerably increased the absolute population of the pest without affecting cauliflower yield. Approximately seven times as many flies were produced per unit area of untreated mini-cauliflowers as from an equivalent area of plants growing at a conventional density. When chlorfenvinphos was not applied, damage by the cabbage stem weevil occurred in 30% and 70% of the plants grown at the lowest and highest densities, respectively.

Observations were made on the developmental responses of the North American braconid species, Eubazus crassigaster, a parasitoid of the white pine weevil, Pissoles strobi, and three European congeneric species, E. semirugosus, E. robustus, and Eubazus sp. Several populations of Eubazus spp. were compared in their phenology in the laboratory and under natural conditions. When reared in the laboratory on non-diapausing Pissodes castaneus, mountain populations of E. semirugosus and E. robustus entered into an obligatory diapause in the host larva, whereas all the other populations tested developed continuously. Diapausing larvae continued their development only after having experienced at least three months at 2°C. Non-diapausing populations of Eubazus spp. significantly differed in the duration of pre-imaginal development, with E. semirugosus being the fastest developing species and E. robustus the slowest. Outdoor rearings of Eubazus spp. on P. castaneus showed that E. crassigaster, Eubazus sp. and the lowland biotype of E. semirugosus emerged in the year of oviposition if this occurred early enough to allow parasitoid development. In contrast, a majority of E. robustus individuals overwintered in the host larvae, regardless of the oviposition date. The diapausing, mountain biotype of E. semirugosus is considered as the most promising candidate for control of P. strobi in Canada, because it is likely to be better adapted to the life cycle of the target host than the other Eubazus spp., including the native E. crassigaster.

The synthetic sex attractant of the pink bollworm of cotton, Pectinophora gossypiella (Saund.) (Lepidoptera, Gelechiidae), is a mixture of (Z, Z) and (Z, E)-7, 11-hexadecadien-l-ol acetate, referred to as gossyplure (Hummel et al., 1973). Field trials in the Lower Shire Valley, Malawi, have shown that of various mixtures tested, 55–60% of the (Z,Z) isomer in a mixture of the two acetates gives maximum field attraction. The catches of both pink bollworm males and males of the red bollworm of cotton, Diparopsis castanea Hmps., in pheromone traps are not affected by the release of mixtures of the pheromones of both species together. Dual-purpose sex pheromone traps may therefore be used to monitor both pest species at the same time. A simple omnidirectional flat disc trap is as efficient in trapping pink bollworm males as more complex designs. Release of gossyplure from a sealed 2·5 ml polyethylene vial or from a Zoecon beem-polyethylene vial is more efficient than from narrow-bore teflon capillary. Presence of the antioxidant 2,6-di-tert-butyl-P-cresol at 8·4% w/w gossyplure does not increase the attractive life of the pheromone in the field. Considerable numbers of the Angoumois grain moth Sitotroga cerealella (Ol.) (Tineidae), together with a new species of gelechiid, were occasionally caught by gossyplure lures in cotton fields. Catches of pink bollworm are not influenced by moonlight or trap colour but are significantly influenced by trap area. Maximum catches of males occur between midnight and 04.00 h in June and between 01.00 and 05.00 h in August.

The breeding sites used by three species of the Anopheles gambiae Giles complex were investigated in northern Natal, South Africa. Those used by the two freshwater species, A. arabiensis Patton and A. quadriannulatus (Theobald) were similar, immature stages of both being collected from the same pool at five out of seven localities from which A. arabiensis was recorded. A. quadriannulatus was the most extensively distributed species of the complex and was found in association with A. arabiensis at only five of 49 localities. The difficulty in locating the breeding sites of A. arabiensis is a product of their low density, presumably as a result of the intra-domiciliary, residual insecticide spray programme. A. merus Dönitz larvae and pupae were recorded only in water with a salinity greater than 5 p.p.t. The pH, dissolved oxygen, pool size, turbidity, shade and association with vegetation of water bodies containing A. gambiae s.l. were also recorded and showed no difference between the three species. The importance of distinguishing between winter and summer breeding sites is discussed, as well as the need for entomological consultation prior to agricultural development in endemic malarious areas.

Population densities of honeydew-producing Homoptera were assessed on mature upper-Amazon cocoa (Theobroma cacao) (Sterculiaceae) trees with combinations of the ants Crematogaster clariventris Mayr, Pheidole megacephala (Fabricius) and Tetramorium aculeatum (Mayr). Interactions were found between combinations of the three ant species and the abundance of Homoptera attended for honeydew. Crematogaster clariventris primarily attended Stictococcus sjostedti Cockerell (Stictococcidae), and less frequently Waxiella sp. nr zonata (Newstead) (Coccidae). Pheidole megacephala attended mealybugs, mainly Planococcoides njalensis (Laing), and Planococcus citri (Risso) (both Pseudococcidae). Tetramorium aculeatum was negatively associated with honeydew-producing Homoptera only when it was the sole dominant ant. Where T. aculeatum co-existed with either one, or both, of the other ant species, it had little influence on the abundance of the honeydew-producing Homoptera they attended, including the mealybug vectors of cocoa swollen shoot virus. Ant-attended Homoptera were more numerous on trees solely dominated by their attendant ants than on trees where two or all three ant species co-occurred. By contrast, the non-ant-attended psyllid Mesohomotoma tessmanni (Aulmann) was least common on trees with a single dominant ant species, and was most abundant on trees foraged by all three ant species.

Under simulated natural conditions the anal orifice of the larva of Glossina morsitans morsitans Westw. appears to open either at or soon after parturition. The larva burrows on average within two minutes of deposition; pupariation is completed 10–15 min later. Using methods that prevent burrowing and prolong the crawling period, certain larval movements were related to the pre-pupariation anal discharges and to the rapid spread of the fluid. Although the anus is not generally thought to be connected with the hind gut during the whole of larval life, the presence of uric acid in the discharges indicates that the fluid is a product of Malpighian tubule excretion. In a two-choice chamber in an incubator, flies larviposited significantly more often in the experimental pot if it contained a water- or ether-soluble extract of larval excretion in addition to any pupariating larvae. This points to the presence of a larval phero-mone which may attract gravid females to a breeding site.

The present paper attempts to summarise the information collected by the Imperial Institute of Entomology on the swarming of migratorioides in Africa.

It is concluded that the outbreaks in West, Central and East Africa are all interrelated and probably originated in one or at most two permanent breeding-grounds.

The area most suspected is the lake district of the middle Niger, where conditions seem suitable for the formation of the swarming phase. Lake Chad is probably a secondary rather than a permanent breeding-ground.

It is indicated that the key to the problem of the cause of the original outbreak may be found in the study of recent variations in the water régime of the River Niger.

Should these suppositions be substantiated, we are well on the way towards a solution of the problem. The ultimate control of the locusts depends not on control during the swarming periods, but upon preventing the swarming phase from developing in the permanent breeding-grounds.

It is therefore important to check and augment the records of the early swarms in West Africa and more important still, to study the behaviour of the locust, its ecology, and the water régime in the suspected areas.

In conclusion the author wishes to acknowledge the constant help and advice of Mr. B. P. Uvarov. His thanks are also due to Mr. H. B. Johnston for his permission to make use of his paper in manuscript.

Field studies of predators on Aulacaspis tegalensis (Zhnt.) and laboratory breeding experiments, supplemented by taxonomic studies, showed that Chilocorus discoideus Crotch and C. bilineata Korsch. are junior synonyms of C. schioedtei Muls. and that two other forms, originally described as ‘aberrations’, may also belong to this species. Similarly, C. erythrocephalus Muls. and C. solitus Weise are junior synonyms of C. distigma (Klug). C. rufoplagiatus sp. n., allied to C. distigma, is described from the shores of Lake Victoria, and the Oriental species C. nigritus (F.) is recorded from the African mainland for the first time. C. distigma is found in the savanna and steppe areas of Africa and C. schioedtei in the forest and adjoining zones. Comparative studies suggest that, although C. schioedtei has a higher fecundity, it is not displaced by C. distigma as, unlike the latter, it is unable to breed under hot dry conditions. Comparison of host records for these two species show that C. distigma is not restricted to feeding on Diaspididae, as is C. schioedtei, but that otherwise the range of hosts and associated plants is similar for both species. The potential of these species and C. nigritus for use in biological control is discussed and it is suggested that C. schioedtei is only suitable for trial in tropical areas without a dry season, but that C. distigma and C. nigritus may be useful under a wider range of conditions.

In field populations of Lucilia cuprina (Wiedemann) in Australia, there was a very low percentage of mating in females that, on the evidence of their stage of ovarian development, had not yet consumed protein-rich material. Virtually all females whose oocytes had reached early vitellogenesis had mated. Thus, most females of this anautogenous species had mated soon after their ovarian development had proceeded beyond the resting stage at which development ceases in females that have not consumed protein. The relationship between mated status and ovarian development of hand-caught females did not differ from that for females which had been allowed to remain for more than 1 h with sexually active males in the collection chamber of traps. Thus mating occurred rarely, if at all, in the trap chambers, which suggests that females in the field mate soon after first becoming sexually receptive. This, together with knowledge that females of this species do not remate readily, indicates that the operational sex ratio in L. cuprina is heavily male-biased.

Insect population dynamics depend strongly on environmental factors. For floodwater mosquitoes, meteorological conditions are crucial in the rhythm of mosquito abundances. Indeed, rainfall triggers the egg hatching after flooding breeding sites, and temperature controls the duration of the aquatic immature development up to adult emergence.

According to this, we have developed a simple mechanistic and tractable model that describes the population dynamics of floodwater mosquitoes as a function only of the most accessible meteorological variables, rainfall and temperature. The model involves three parameters: development duration tdev of the immature aquatic stages, the adult emergence rate function f(t) (characterized by the emergence time scale τ and shaping the profile of adult population abundance), and the depletion rate, α, of adult disappearance.

The developed model was subsequently applied to fit experimental field data of the dynamics of Aedes caspius (Pallas), the main pest mosquito in southern France. First, it was found that the emergence rate function of adult mosquitoes very well reproduce experimental data of the dynamics of immature development for all sampled temperatures. The estimated values of tdev and τ both exhibit Arrhenius behaviour as a function of temperature. Second, using the meteorological records of rainfall and temperature as inputs, the model correctly fit data from a two-site CO2 trapping survey conducted in 2004 and 2005. The estimated depletion rates (summation of the mortality and the emigration rates) were found to be a concave quadratic function of temperature with a maximum of 0.5 per days at about 22°C.

The build-up of resistance to phosphine and methyl bromide in the developmental stages of Tribolium castaneum (Herbst) after six selections in successive generations was investigated in the laboratory at 25 ± 1°C. Responses of the life stages of the fumigant-selected insects were compared with those of untreated controls with a 24 h exposure and mortality was assessed after 14 days. Phosphine induced the development of resistance irrespective of the life stage chosen for selection. The onset of phosphine resistance was noted after the first selection but the levels of resistance attained in the different stages varied depending on the stage tested, and in each case the degree of expression was different in the four stages of T. castaneum. After selection, phosphine resistance was highest in the pupae followed by eggs, adults and larvae. Resistance to methyl bromide in the methyl bromide treated insects increased only slightly (less than × 2.0). Adults derived from egg, larva, pupa and adult-selected methyl bromide lines showed cross-resistance to phosphine (× 1.8 to 11.5 at LD95), while cross-resistance of adults to methyl bromide was noted only in adult-selected phosphine-resistant insects (× 1.5 at LD95).

Previous work on strains of Amphorophora rubi (Kalt.) is discussed and evidence is presented to show that the form on European raspberry can be divided into three strains. These are designated European raspberry strain 1, 2 and 3. The distribution, abundance and importance of the strains in relation to plant breeding for resistance to A. rubi is discussed.

Observations in eastern England during 1957, 1958 and 1959 showed natural mortality of pupae of wheat bulb fly, Leptohylemyia coarctata (Fall.), to be high. The part of this due to parasitisation is considered in some detail.

At Rothamsted, the main parasite was Trybliographa spaniandra Kerrich & Quinlan, and this affected about 10 per cent, of the population in 1957 and about 5 per cent, in 1958. At Whittlesey and Peterborough, in 1959, parasitisation affected 5·5 and 13·7 per cent, of the populations, respectively. The two main parasites found were Aleochara bipustulata (L.) and A. inconspicua Aubé (Coleoptera, Staphylinidae). Phygadeuon trichops Thoms. (Hymenoptera, Ichneumonidae) also occurred but was much less frequent. Notes and original observations on the biology of these parasites are given.

Several insects and other small arthropods were observed to prey on various stages of wheat bulb fly. Details of these and notes on the biology of some of them are given.

The mealybug Phenacoccus herreni Cox & Williams causes considerable damage to cassava Manihot esculenta Crantz. Field surveys conducted between 1988 and 1994 indicated the mealybug was present in 57 municipalities in six States in north-eastern Brazil, in some places reaching high levels of infestation. Several native natural enemy species were found associated with the pest in Brazil. Exotic encyrtid parasitoids were imported and released in fields in the States of Bahia and Pernambuco. Apoanagyrus diversicornis (Howard) was introduced from Colombia, and Acerophagus coccois Smith, and Aenasius vexans (Kerrich) were introduced from Venezuela. By the end of 1996, a total of 35,930 parasitoids had been released. In Bahia, Apoanagyrus diversicornis was recovered 130, 234, 304 and 550 km from its release site after 6, 14, 21 and 33 months, respectively. Acerophagus coccois was recovered at 180 km from its release site nine months after release. Aenasius vexans, however, did not disperse at all despite being consistently recovered at its release site. In Pernambuco, 9010 parasitoids were released from October, 1995 onwards. Acerophagus coccois and Aenasius vexans were recovered up to 40 km from the release sites after three and five months of their initial releases, respectively. The establishment and dispersal of these parasitoids are discussed.

Game animals were shot in an isolated area of some 600 sq. miles over a period of about five years. The density of animals was originally in the neighbourhood of 10 to the sq. mile.

This density is very low compared with densities recorded from national parks, and examination of the evidence available shows that the Tanganyikan bushland is understocked with game.

As the result of the shooting in the present experiment, two species of tsetse fly, G. morsitans and G. swynnertoni, were exterminated, and a third, G. pallidipes, was either exterminated or very heavily reduced. Experimental cattle then remained healthy in the area for 11 months, after which they were removed.

This result was achieved in spite of considerable invasion of the area by cattle, particularly intense at a late period when such an alternative source of food might have been expected to be particularly valuable to the tsetse.

There was evidence that the fat, residual dry weight and size of the flies decreased, but there was no apparent effect on mean age or the proportion of females in the catches, nor apparently did the flies turn to avian blood.

The cost was £50 per sq. mile; but this figure would be very much greater in normal practice, with areas not isolated from the rest of the fly belt.

Game destruction is not recommended except in isolated areas of manageable size; discriminative clearing of the habitats, even at initially greater cost, is preferable as offering a more lasting solution.

We examined the role of the most important metabolic enzyme families in the detoxification of neurotoxic insecticides on adult males and females from susceptible populations of Cydia pomonella (L.), Grapholita molesta (Busck), and Lobesia botrana (Denis & Schiffermüller). The interaction between the enzyme families – carboxylesterases (EST), glutathione-S-transferases (GST), and polysubstrate monooxygenases (PSMO) – with the insecticides – chlorpyrifos, λ-cyhalothrin, and thiacloprid – was studied. Insect mortality arising from the insecticides, with the application of enzyme inhibitors – S,S,S-tributyl phosphorotrithioate (DEF), diethyl maleate (DEM), and piperonyl butoxide (PBO) – was first determined. The inhibitors' influence on EST, GST, and PSMO activity was quantified. EST and PSMO (the phase-I enzymatic activities) were involved in the insecticide detoxification in the three species for both sexes, highlighting the role of EST, whereas GST (phase-II enzymes) was involved only in G. molesta insecticide detoxification. L. botrana exhibited, in general, the highest level of enzymatic activity, with a significantly higher EST activity compared with the other species. It was the only species with differences in the response between sexes, with higher GST and PSMO activity in females than in males, which can be explained as the lower susceptibility of the females to the tested insecticides. A positive correlation between PSMO activity and the thiacloprid LD50s in the different species-sex groups was observed explaining the species-specific differences in susceptibility to the product reported in a previous study.

It is considered desirable to place on record some data relating to insects attacking economic plants in Sierra Leone; little information has hitherto been available, and it is hoped that this list will prove of interest and use to other workers. Families, genera and species are arranged alphabetically.

Three new prototype traps, (S1–S3), were developed during studies of the behavioural ecology of Glossina swynnertoni Austen in Kenya and Tanzania. The traps were compared in latin square experiments relative to the regular biconical trap as a standard and a selection of other conventional tsetse traps. Observations were also made on fly behaviour in the vicinity of traps using electric nets and sticky materials. When baited with acetone and 1-octen-3-ol, the S1 trap was 3.5 times as effective in catching G. swynnertoni in Kenya as the biconical trap. In Tanzania, the relative performance of the S1 and biconical traps differed; also, both traps were found to be inferior to an all-black, sticky 1-m2target. A second prototype (S2) performed slightly better than the biconical trap, but was still inferior to the black target. The final prototype (S3) was 2.9 times as effective as the biconical trap and performed as well as the black target. The potential for further improvement of traps for capturing G. swynnertoni and flies of the G. morsitans Westwood group is discussed.