Soil samples were taken from two transects (total 63 sampling points; 25 cm quadrats) representing the Betula pubescens (Betulaceae) woodland, rush-pasture and peat-based mire vegetation of the west coast and Highlands of Scotland, in an attempt to relate soil and vegetation features to the occurrence of Culicoides impunctatus Goetghebuer larvae. The covers of vegetation groups were recorded at each sample site and soil wetness was assessed on an arbitrary scale. Culicoides spp. larvae were extracted from half of each sample and stored for subsequent identification of C. impunctatus larvae, while the remaining half was used for analysis of soil pH and organic content (loss on ignition, LOI). Correspondence analysis (using DECORANA) separated the sample sites and vegetation groups and the ordination axes were significantly correlated with the density of C. impunctatus larvae, soil organic content and soil wetness index. Simple regression analyses revealed that the density of Juncus acutiflorus/J. articulatus (Juncaceae) and soil wetness index were positively related to the overall variation in C. impunctatus larval density. The wetness index had the strongest relationship and this remained the case in step-wise multiple regression. There was no relationship between larval density and soil pH. This information on the specific microhabitat preferences of the larvae could aid colonization attempts of this dominantly important species of biting midge in the UK.

Very late on a dark Saturday night in 1953, in the town of Kumasi in what was then the Gold Coast (Ghana), a semi-literate Tribal Policeman accosted a totally illiterate and inebriated employee of mine called Awuni Farafara, with the words ‘Who be You’. Awuni's reply of ‘I be Me’, caused the policeman to retort ‘You Lie!’ and the luckless Awuni was incarcerated for ‘failing to identify himself and thereby hindering the police in the performance of their duty’.

My plea, on his behalf, that Awuni's reply to the policeman was perfectly correct was rejected on the grounds that, ‘Me was not his given name; Me was not the name by which he was known; and Me was not the name by which the police could check their records to see what was known about him’. It further transpired that even if Awuni had given his correct name he would still have been arrested, ‘because it could have been a false name leading the police to false information in their records’. Awuni it seemed was destined to remain in jail until ‘he had been properly identified by someone with the authority to do so’. I had such authority; I did properly identify him; and he was released.

The systematics of the hymenopterous parasitoids associated with Phoracantha spp. in Australia are reviewed. An illustrated key to species is presented to facilitate their identification as part of ongoing attempts for the biological control of P. semipunctata (Fabricius), an exotic pest on eucalypt trees. Information on the taxonomy, distribution and biology of 18 species of primary and hyperparasitoids associated with Phoracantha spp. are presented. A new braconid genus, Jarra, is described to accommodate three new species, J. phoracantha, J. maculipennis and J. bicolor, and Doryctes diadoxi Nixon (Doryctinae), the latter associated with a buprestid host. Two other new species, Heterospilus nukunu (Doryctinae) and Callibracon moorei (Braconinae) are also described; Iphiaulax morleyi Froggatt is synonymized with Atanycolus tomentosus Szépligeti and I. rubriceps Froggatt is synonymized with Syngaster lepidus Brullé lectotypes are designated for I. morleyi, I. rubriceps and I. phoracanthae Froggatt; and Ipobracon fleviceps flaviceps (Cameron) and I. flaviceps mackayensis Turner are transferred to Callibracon. The encyrtid genus Aventianella is recorded from Australia for the first time and the egg parasitoid of P. semipunctata, A. longoi Siscaro described from Italy, is postulated to be endemic to Australia.

To study the rate of invasion into brood cells, a group of varroa mites, Varroa jacobsoni Oudemans, was introduced into honeybee colonies, Apis mellifera Linnaeus. For each experiment one or two otherwise comparable colonies was treated, and the effect on the rate of invasion was assessed. The results showed that the rate of invasion increases with the number of available brood cells, and decreases with the size of the honeybee population. This is expected when the rate of invasion is limited because the bees have to carry the mites close to a brood cell for invasion to occur, and only alimited number of honeybees can come close enough to a brood cell simultaneously. In addition, the rate of invasion decreased when young brood was present. This counterintuitive result may arise because the mites prefer young honeybees, young honeybees are likely to stay in the brood nest area, and young honeybees in the brood nest are divided over areas with brood cells that are suitable for invasion and over areas with brood cells that are unsuitable for invasion by mites. Hence, an increase in the amount of young brood, which is not yet suitable for invasion by mites, may decrease the invasion rate. Differences in the period during which brood cells suitable for mite invasion were available to the mites, appeared not to affect the rate of invasion.

An experiment was conducted at Galana Ranch, Kenya, which examined, under natural conditions, whether treatment of oxen with insecticidal pour-ons affects the success with which tsetse flies (Glossina pallidipes Austen) feed on them. An incomplete ring of electric nets was used to sample G. pallidipes approaching and departing from oxen that were either untreated, or treated 6–12 days previously with pour-ons containing deltamethrin or cypermethrin. Eight animals of each treatment were used. There was no evidence suggesting that pour-on application affected the number of G. pallidipes attracted to oxen. A positive relationship was observed between the number of G. pallidipes that approached an ox and the frequency with which it made anti-fly movements. There was also a significant, negative relationship between the rate of anti-fly movements and the proportion of G. pallidipes that fed on the oxen. However, there was no effect of pour-on application on either the rate of anti-fly movement or on the proportion of tsetse that fed. It is concluded that even recent application of deltamethrin or cypermethrin pour-ons to an ox does not affect the ability of G. pallidipes to feed; and that the feeding success of G. pallidipes is density dependent because when more tsetse approach an ox its rate of anti-fly movements increases and the proportion of tsetse that feed decreases.

Female Aphidius rhopalosiphi De Stefani Perez reared on Rhopalosiphum padi (Linnaeus) made equal numbers of encounters with another suitable host aphid (Sitobion avenae (Fabricius (both Homoptera: Aphididae))) in arenas where the aphids were on either pieces of wheat leaf or moist filter paper. However, the number of oviposition stabs made in arenas with wheat was far higher than with filter paper, demonstrating the importance of host-plant cues in the acceptance of the aphids by the parasitoid. Diet reared aphids (even if subsequently fed on wheat) appeared to be accepted more readily than totally wheat reared individuals. In another arena experiment, there were more encounters with and more stabs made into both S. avenae and a non-host aphid (Myzus persicae (Sulzer)) on wheat than on Brussels sprouts (a host plant of M. persicae), again showing the over-riding importance of host-plant cues.

The responses of adult females of Hypothenemus hampei (Ferrari) from New Caledonia, which were either resistant or susceptible to endosulfan, were compared to a range of insecticides. High levels of cross resistance were present to organochlorines (aldrin, dieldrin and lindane). No cross resistance was evident to carbaryl or organophosphates (descending order of toxicity: fenitrothion > pirimiphos-methyl > chlorpyrifos > diazinon=malathion). Carbaryl, a carbamate, was the least toxic, and avermectin, a macrocyclic lactone, was the most toxic insecticide tested on H. hampei. No evidence of synergy from esterase (DEF) or microsomal oxidase (piperonyl butoxide) inhibitors was present.

A previous study on the population dynamics of the cassava mealybug, Phenacoccus manihoti (Matile-Ferrero), on cassava has shown that populations increase during the dry season. The aim of the present studies was to determine whether these important changes in the pest population observed throughout the seasons in the field in the Congo, could be correlated with seasonal variations in the level of secondary compounds in the phloem, implicated in cassava plant resistance to P. manihoti. Our results showed that cassava was in drought stress conditions during the dry season (foliar area decreased). The combination of infestation and dry stress factors was clearly visible during the dry season. In fact, the decrease in leaf water potential together with infestation by P. manihoti was clearly observed at the end of the rainy season and during the dry season. The levels of the secondary compounds, rutin (an unfavourable substance to P. manihoti) decreased in the less resistant genotype, and cyanide (a phagostimulant substance) increased in each genotype in the dry season. These results may partially explain the important population changes in P. manihoti during the seasons.

Two acetylcholinesterase (AChE) variants, differing in sensitivity to inhibition by the organophosphorus (OP) insecticide paraoxon were identified in a population of Bemisia tabaci (Gennadius) from cotton in Israel using a single insect kinetic microplate assay. Two strains were established, homogeneous for one or other of the two variants, by isolating mated females from the field population onto individual cotton leaves, and testing a proportion of their female offspring to identify their AChE genotype. Polyacrylamide gel electrophoresis of their I-naphthyl butyrate hydrolyzing esterases showed that all insects contained esterase E0 14, which is indicative of B-type whiteflies, although the staining intensity of this band differed. Resistance to the OPs monocrotophos, profenofos and chlorpyrifos in leaf dip bioassays was consistent with the presence of the insensitive AChE. The data also indicated that separate mechanisms conferred resistance to the two pyrethroids cypermethrin and bifenthrin. The former, when used in a mixture with profenofos, was no more toxic than when the OP was used alone, and resistance to the mixture was largely dependent on the presence of the insensitive AChE.

The coffee berry borer Hypothenemus hampei (Ferrari) has recently evolved high levels of resistance to endosulfan and other cyclodiene-type insecticides in New Caledonia. During population outbreaks this has contributed to levels of infestation of coffee berries reaching up to 90%. Using degenerate primers in the polymerase chain reaction (PCR) we have amplified a section of the cyclodiene resistance gene Rdl from H. hampei. This gene codes for a γ-aminobutyric acid (GABA) gated chloride ion channel. Here we report that resistant strains of H. hampei carry exactly the same single amino acid replacement (alanine to serine) as that found in resistant Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). A molecular diagnostic based upon PCR-mediated amplification of specific alleles (PASA) is described. This technique is capable of detecting resistance or susceptibility in adults, larvae or eggs but not in susceptible females carrying resistant sperm. Its potential use in field monitoring is discussed.

Leuronota calycophylli sp. n. attacks experimental plantations of the high-quality timber Calycophyllum spruceanum in Peru. Adults, larvae and the damage on the host are described and illustrated. Adults differ from other congeners in the absence of genal processes and in the structure of the genitalia. The host of L. calycophylli is unusual for psylloids: rubiacious hosts are otherwise known only from the four members of the Palaearctic Trioza galii Förster group and the Taiwanese Synpsylla wendlandiae Yang.

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.

Host characteristics, hyperparasitism, larviposition behaviour and generation time of Sarcophaga penicillata Villeneuve a parasitoid of the conical snail, Cochlicella acuta Müller (Mollusca: Helicidae) in southern France are described. Only snails which aestivated on vegetation were found to be parasitized by S. penicillata. Sarcophaga penicillata preferred C. acuta which were both significantly higher off the ground and larger in size than the population averages. Of the 2768 snails collected at the study site, 4% (112) were parasitized by S. penicillata, of which 36.6% (41) failed to emerge while 34% (38) were hyperparasitized. The predominant hyperparasite was Novitzkyanus cryplogaster Bouček (Hymenoptera: Pteromalidae) which was responsible for 79% (30) of the hyperparasitism. Larvipositing S. penicillata were observed to fabricate a hole in the epiphragm of resting snails in which they deposited one larva. After larviposition, female S. penicillata remained with the freshly parasitized snail a mean time ± SE of 25.2 ± 10.3 min. It is suggested that this may be an adaptive response to avoid superparasitism. The mean generation time of S. penicillata when reared in the laboratory was 18 days, indicating that more than six generations are possible during summer in the south of France. During winter, S. penicillata enters diapause in the pupal stage within a host snail for up to 6 months. The possible utility of S. penicillata as a biological control agent of introduced conical snails is discussed.

Significant inter-crop variation in the abundance of phlebotomine sandflies, mostly Lutzomyia verrucarum Townsend, and five aphid species (Hemiptera: Aphididae), was demonstrated by repeated castor oil sticky trap collections in two valleys in the Peruvian Andes. Sandfly populations were significantly higher in fruit crops than in ground crops. Sticky trap collections also proved to be a suitable method for measuring aphid relative abundance in crops. As aphid honeydew is a natural sugar source for phlebotomine sandflies, the relationship between the activities of sandflies and aphids was investigated in inter-crop comparisons. Significant correlations were detected between sandfly abundance and two of the major aphid species, Aphis gossypii Glover and Eriosoma lanigerum (Hausmann), in one valley, but indirect explanations for these apparent associations cannot be ruled out.

Catches of moths in tower-mounted light traps in northern New South Wales were analysed in relation to local and synoptic weather. Catches were correlated with windspeed, relative humidity and possibly rainfall. No correlations were obtained with temperature or moon phase. Catches were more likely to occur when winds were from the east, and were associated with wind shifts. There was a significant association with the passage of depressions or troughs, but not cold fronts. The traps were considered to be poor indicators of migration associated with fronts, because these were accompanied by high winds in which trap efficiency was reduced. Stepwise multiple regressions using temperature, relative humidity, rainfall and windspeed accounted for only about 25% of the variance, much lower than in comparable studies with ground level light traps. These results are thought to indicate that the trap catches were reflecting long-distance migration, which was usually associated with disturbed weather. Back tracking with upper wind data was used to define probable sources of moths. In the spring and early summer, these sources were predominantly to the north and west of the traps, in semi-arid pastoral and subhumid cropping zones. In the late summer and autumn they were predominantly to the south and east, in the humid pastoral and forest zone. These results are discussed in relation to the migratory strategies of several important agricultural pest species.

The overwintering stages of the carrot fly (Psila rosae (Fabricius)) were sampled at Wellesbourne, Warwickshire, during the winters of 1987, 1988, 1989 and 1990. Between 20% and 55% of the insects overwintered as pupae in diapause. The remaining insects stayed in the larval stage during the winter period and gave rise to non-diapausing pupae in the early spring. In May, adults emerged earlier, and over a shorter period, from insects that overwintered as larvae than those that overwintered as pupae. Diapause was most intense during late December and early January. In the laboratory, diapause was completed at temperatures of 5°C and above but was not completed at 0°C. When the overwintering stages were sampled in early February and maintained at constant temperatures in the laboratory, the overwintering pupae required from 114 days at 9°C to 44 days at 21.5°C to give rise to adults. In contrast, the overwintering larvae required only 91 days (9°C) and 27 days (21.5°C), respectively. Populations of overwintering P. rosae collected from Warwickshire and Norfolk had similar requirements for spring emergence but diapause pupae collected in Lancashire emerged over a longer period of time than those collected in Warwickshire. Comparisons with published data indicated that North American and European pupae had different requirements for the completion of diapause. Accumulation of weather data for a P. rosae forecast should start when temperatures are low and any date in early February would be suitable.

CDC (Communicable Disease Center) light-traps were compared with human-bait collections as an alternative method for sampling malaria vectors in two villages of western Kenya. The numbers of Anopheles funestus Giles and Anopheles gambiae sensu lato Giles in CDC light-trap collections were significantly correlated to the numbers caught in human-bait collections, but in Anopheles arabiensis Patton the two collections were not significantly correlated. Most of the female vectors collected in the traps were unfed. Parity of A. arabiensis collected in CDC light-traps (44.3%) was significantly lower than the rate obtained from females caught on human-bait (54.5%). Although CDC light-traps provide a cheap and convenient method for collecting vectors, further studies should nevertheless be undertaken to determine the influence of species-specific variation in the sizes and age-structure of collections because such variations can affect the epidemiological interpretation of the data.

Suppression tactics for the citrus stink bug pest, Biprorulus bibax Breddin, were developed and implemented during 1987–1992 in four lemon orchards in southern New South Wales, Australia. Tactics were based on introduction and conservation of natural enemies (principally egg parasitoids), physical or chemical treatment of overwintering populations and strategic low rate applications of a selective insecticide. Estimated adult populations of 10–35,000/1.5 ha and 70–90% fruit damage in untreated crops were reduced to <500/1.5 ha and <5%, respectively, following full implementation of the management programme. Integrated management of B. bibax removes the need for broad-spectrum insecticides to control this pest and lessens the risk of disruption to biological control of other citrus pests.

Spodophagus, gen. n. (Pteromalidae: Pteromalinae), is described to include the single species S. lepidopteraecomb. n., which was originally described from Madagascar by Risbec (1952) in the genus Oxyglypta. A lectotype is selected for O. lepidopterae, and the species is redescribed and illustrated. This pteromalid is a parasitoid of Spodoptera littoralis, an important pest, which is resistant to several classes of insecticides in Madagascar. Spodophagus lepidopterae is thus a potential agent for the biological control of Spodoptera spp. in Africa and elsewhere.