Between 1908 and 1959, the predatory coccinellid, Hyperaspis pantherina Fürsch, was released for the biological control of the ensign scale Orthezia insignis Browne in Hawaii, four African countries and Peru. Substantial control was reported after all the releases, although the outcome was disputed in Malawi. Other coccinellid species and predatory Diptera were released against Orthezia spp. in various programmes from 1952 to 1977. In most cases these agents failed to establish, and there were no reported effects on the target Orthezia spp. In 1993, H. pantherina was released in St Helena for the control of O. insignis on the endemic gumwood tree, Comm idendrum robustum (Compositae). Preparatory investigations for this release revealed that the taxonomy and biology of this biocontrol agent were poorly known. Hyperaspis pantherina is redescribed and shown to be the correct name for the species previously known incorrectly as H. jocosa (Mulsant). Hyperaspis laeta Gorham and H. levrati (Mulsant) are transferred to the genus Cyra Mulsant (comb. n.). Hyperaspis metator (Casey) (stat. rev.) is resurrected from synonymy with H. levrati auctt. Studies of the life history revealed that H. pantherina normally lays its eggs directly onto the adult female O. insignis and that the first two instars of the larvae are frequently passed inside the ovisac of the female host, after which the host itself is often consumed. The information on the biology and taxonomy of H. pantherina, together with details of culturing methods, should facilitate the further use of this agent for the classical biological control of O. insignis, a pantropical pest.

Lutzomyia verrucarum (Townsend) is an abundant anthropophilic phlebotomine sandfly in the Peruvian Andes between 1500 m and 3000 m asl, where it has been incriminated as a vector of both Leishmania peruviana (cutaneous leishmaniasis) and Bartonella bacilliformis (bartonellosis). Previous studies of this vector demonstrated that sandfly activity, measured by sticky traps, was related to crop type. In this paper, we report the results of a field experiment in Peru (Department of Ancash) which show that a single human host in a crop does not attract Lu. verrucarum from distances of 5 m or more, and that there is a positive correlation between the number of Lu. verrucarum collected by sticky traps and the number attracted to a human host in the same field. The results imply that variation in sandfly activity between crop types could lead to differential risk of both leishmaniasis and bartonellosis for humans working at night in different crops.

Helicoverpa armigera (Hübner) and H. punctigera (Wallengren) are major pests of cotton in Australia. The density of eggs and larvae of these species are sampled regularly throughout the growing season to assess the need for insecticidal control. A sampling system now widely used is based on binomial sampling combined with a series of conversion relationships developed as part of the SIRATAC computer based pest management system established in the early 1980s. A three year study was initiated to reassess the binomial sampling conversion relationship in the light of changed agronomic practices and new cotton varieties. New relationships were established to predict the mean number of Helicoverpa spp. present, based upon the number of infested plants found within a sample. Relationships are reported for the sampling of whole plants and the sampling of the terminal (top 20 cm) portion of cotton plants only. These new relationships will be incorporated into entomoLOGIC, a personal computer based pest management system now released to replace SIRATAC.

The effectiveness of a sex pheromone trap designed specifically to deliver conidia (infective fungal propagules) of the entomopathogenic fungus Zoophthora radicans Brefeld (Zygomycetes: Entomophthorales) to male Plutella xylostella (Linnaeus) was investigated. In field experiments in the Cameron Highlands of Malaysia, synthetic pheromone lures attracted adult males P. xylostella at all times of the day whereas lures of virgin female moths attracted males only between the hours of dusk and dawn, when females are known to produce their pheromone. Adult male moths attracted to traps baited with synthetic pheromone spent a geometric mean time of 88 seconds within the inoculation chamber, a time compatible with the period adults must spend within a shower of Z. radicans conidia produced by uniform mycelial mats in order to become infected. The field longevity of male and female P. xylostella adults was found to be similar, with individuals living for a mean time of 4.9 days. This was sufficient time for male moths to respond to the pheromone, enter the trap, become infected with Z. radicans and succumb to that infection in the field (3–3.5 days) thereby releasing infective conidia into the cabbage crop.

A method for physiological age determination in blackflies is described from studies on Simulium equinum (Linnaeus), S. ornatum Meigen, S. erythrocephalum (De Geer), and S. nigrum (Meigen) in Russia, and S. vittatum (Zetterstedt), and S.verecundum-venustum supercomplex in Canada. The method uses neutral red to stain the ovariolar structures which indicate preceding gonotrophic cycles. Two different processes can occur in the ovariole during the gonotrophic cycle: egg development with ovulation, or degeneration of a terminal follicle. Egg-sacs are resorbed and form zones of granulation which accumulate in the ovariole at each gonotrophic cycle. Following degeneration of the terminal follicle, a follicular relic (═gonotrophic dilatation) forms. The sum of zones of granulation plus follicular relics in each ovariole can indicate the number of completed gonotrophic cycles. However the number of follicular relics alone does not correspond to the number of preceding gonotrophic cycles and cannot reliably be used for determination of the parity of a female. Female flies collected in nature were categorized as: nulliparous; 1-parous; or multiparous. In multiparous females, most ovarioles have no more than two zones of granulation or a combination consisting of one zone of granulation and a follicular relic. Females in this category are considered to be 2-parous. In some ovarioles of parous females the germarium and terminal follicles were found to have disappeared.

Three highly repetitive DNA sequences Rp36, Rp217 and Rp234, have been isolated from Anopheles culicifacies Giles sensu lato. The cloned DNA sequences were found at a higher copy number in species B and C, than in species A of the A. culicifacies complex. These sequences may therefore be used as DNA probes to distinguish species A from the other two species, using a 200-fold dilution of a single mosquito DNA extract in a dot-blot hybridization assay. Rp36 and Rp217 have been completely sequenced. Internal repeats were absent in Rp36. Two related core sequences of 13 and 16 bp were found tandemly repeated in Rp217. These probes enable the rapid detection of species A of A. culicifacies in field investigations.

The vertical and horizontal distribution of Tribolium castaneum (Herbst) in a rice warehouse was studied using flight traps hung around selected stacks of bagged rice. Traps hung at 4 m or higher from the floor caught more T. castaneum than other insect species in the warehouse. At 6 m height, the traps caught mainly this species and were easy to maintain. The horizontal distribution pattern of T. castaneum sampled at 6 m was not homogeneous. The factors influencing distribution are discussed.

The bioactivity of materials from the leaves of Ocimum kilimandscharicum was tested against Sitophilus zeamais Mots chulsky (Coleoptera: Curculionidae), Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) and Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) in maize and sorghum grains in the laboratory. Exposure of adults of the three insect species to dried ground leaves and essential oil extract of O. kilimandscharicum induced 100% mortality after 48 h. Fresh and dried whole leaves were not toxic to Sitophilus zeamais or R. dominica. Grains treated with dried ground leaves and essential oil extract caused significant reductions in the number of progeny and survival rate of all three pest species tested. There was no adult survival or progeny production in grains treated separately with each of the two materials at doses of 25.0 g (dried ground leaves) and 0.3 g (essential oil) per 250 g of grain, respectively. Unlike R. dominica and Sitotroga cerealella, grains treated with fresh leaves enhanced the feeding activity of Sitophilus zeamais. Ground leaves and the essential oil, however, protected the grains against feeding by all three species, resulting in lower weight loss and number of damaged seeds compared with untreated grains. All the plant materials were repellent to S. zeamais with the essential oil extract applied at 0.3 g/250 g of grain evoking the highest repellent action. There was, however, considerable variation in the repellency of the materials against R. dominica and Sitotroga cerealella. The results are discussed in terms of the efficacy of O. kilimandscharicum for protection against loss due to insects in traditional grain storage in developing countries.

Eighteen parasitoids were recorded from the African stem borer, Busseola fusca (Fuller), on maize and grain sorghum, in Delmas and Cedara, South Africa. In Delmas, larval parasitism on both crops fluctuated below 20% with occasional peaks of 40–60%. In Cedara, larval parasitoids were active throughout the season with peaks of 75% and 60% parasitism during January and March-April, respectively on the ratoon crop, and 20% in May on the crop. Pupal parasitism peaked in Cedara at 100% during February-March, and at 80% during November, when parasitoids attacked pupae that formed after B. fusca larvae had emerged from diapause and pupated. In Delmas activity by pupal parasitoids was negligible. The egg parasitoids, Telenomus busseolae Gahan (Hymenoptera: Scelionidae) and Trichogrammatoidea lutea Girault (Hymenoptera: Trichogrammatidae), were rare. The larval parasitoid, Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae), was active throughout the season and was by far the most abundant, emerging from about 90% of parasitized larvae. Its cocoons were often attacked by Aphanogmus fijiensis (Ferrière) (Hymenoptera: Ceraphronidae). Second in abundance among the larval parasitoids was Bracon sesamiae Cameron (Braconidae) whose cocoons were attacked in turn by Eurytoma braconidis Ferrière (Hymenoptera: Eurytomidae). Eurytoma braconidis was reared also from cocoons of Euvipio sp. and Aleiodes sp. (both Braconidae). All other larval parasitoids were rare. Procerochasmias nigromaculatus (Cameron) (Hymenoptera: Ichneumonidae) was the most abundant pupal parasitoid. Trichogrammatoidea lutea, Glyptapanteles maculitarsis (Cameron) (Braconidae) and Odontepyris transvaalensis (De Buysson) (Hymenoptera: Bethylidae) have not been recorded before from B. fusca. Some considerations and proposals for introductions of parasitoids into South Africa against B. fusca are discussed.

Mating behaviour, sex pheromone attraction and reciprocal breeding of Cotesia flavipes Cameron (Hymenoptera: Braconidae), C. sesamiae (Cameron) and C. chilonis (Matsumura) were studied. These three putative species comprise the Cotesia flavipes complex. Wing fanning and antennal vibration were the initial courtship signals from the males. Antennal stroking by the male was also an important contact signal and a prerequisite to successful mounting and copulation. Interspecific crosses revealed that males of C. flavipes exhibited courtship behaviour, and mounted and copulated with females of C. chilonis and C. sesamiae; the males transferred sperm but progeny from these crosses did not include females. Males of C. sesamiae copulated with females of C. chilonis and the progeny included viable females. The progeny backcrosses of the hybrid females to male parents also included viable females. Sex pheromone experiments were conducted in a Y-tube olfactometer and in large field cages. Males and females of C. flavipes perceived and responded to odours emitted by the opposite sex. There was no significant response to odours from conspecific individuals of the same sex in any of the three species. Pheromone bioassays in field cages using sticky traps baited with live virgin C. flavipes females attracted conspecific males.

The probing activities of the most important leafhopper vector of maize streak virus, Cicadulina mbila (Naudé) (Hemiptera: Cicadellidae) were studied on different host-plants. Host preference was determined by giving the insects a choice of six plants, Digitaria sanguinalis, Zea mays, Zea perennis, Paspalum conjugatum, Oryza sativa and Saccharum officinarum (all Gramineae). Cicadulina mbila showed a strong preference for D. sanguinalis. Histological examination of plant tissues for salivary sheaths was used to reveal the preferred tissue. Cicadulina mbila tended to ingest from the phloem of its preferred hosts, and switch to mesophyll or xylem tissue on less preferred hosts. The suitability of each host was assessed by measuring the weight gain and amount of honeydew produced on each host by newly emerged adult females. Both parameters were greatest on the preferred host. Probing behaviour was also monitored electronically by recording the different waveform patterns produced when insects were probing, ingesting or not probing on the selected hosts. Cicadulina mbila probed less frequently, ingested longer and spent less time in non-probing activities on its preferred host, D. sanguinalis, although these responses were similar on maize and sugarcane. Rice induced poor probing responses and altered behaviour. This interpretation of the waveforms was supported by histological examination. As maize streak virus (MSV) is not found in phloem sieve elements, prolonged ingestion from sieve cells would not account for efficient acquisition from maize, which would require ingestion from other types of cells. D. sanguinalis was the host in which most ingestion from the phloem occurred, but it is the poorest source of MSV.

The autumn migration of the rice leaf roller moth, Cnaphalocrocis medinalis Guenée, in eastern China was studied at two sites (one in southern Jiangsu Province and one in northern Jiangxi Province), using radar and aerial netting. It was confirmed that C. medinalis is a high-altitude nocturnal windborne migrant, with large numbers of moths taking-off at dusk and flying continuously for several hours. Migration was post-teneral and the females had immature ovaries. Maximum densities of the moths typically occurred between 250 and 550 m above ground, and layering was intense on some nights. Moth layers often occurred at an altitude where there was a wind-speed maximum. In early September, migrant C. medinalis from southern Jiangsu Province were carried on the winds in an approximately westward direction. However, the winds prevailing in late September and October took migrants from both sites towards the south-west or south. Forward trajectories for C. medinalis and other insects emigrating from northern Jiangxi during October indicated that they were able to reach the tropical rice-growing areas near the south China coast, where year-round breeding would be possible. Incidental observations on the migratory flight of other lepidopteran pests, including Mythimna separata (Walker), Spodoptera litura (Fabricius), Ctenoplusia agnata (Staudinger) and Agrotis ipsilon (Hufnagel) (all Nocturidae), Spoladea recurvalis (Fabricius) and particularly Omiodes indicata (Fabricius) (both Pyralidae) are presented.

Field studies of orientation responses of the IIS-10.11 sibling of Simulium arcticum Malloch species complex and other simuliid species to host-mimicking cattle silhouette traps (CSTs) were carried out in the Athabasca region of Alberta, Canada. Simuliids were attracted to CSTs from downwind by a CO2 bait but very few were attracted to an unbaited CST. Passively searching simuliids tended to fly at lower levels than actively host seeking ones. Simuliids appeared to fly at lower levels when within visual range of the CST than when outside of it. Higher flight levels may improve chances of eventually making visual contact with the host or CST. Experiments in which a CO2 outlet was separated by increasing distances from a CST indicated that simuliids see the 1.1 m long CST at a range of approximately 8 m. Simuliids landing on the CST, whether CO2-baited or not, showed a strong preference for the trap's ends followed by the downwind side, followed by the upwind side. Species composition of collections from CST collections differed significantly from the species composition of cattle sweeps taken at the same times. Simulium vittatum was over-represented in collector catches in comparison to cattle sweeps. This bias may be due to species-specific differences in responses after landing on the CST since sweeps taken around CSTs had compositions similar to cattle sweeps. Results are discussed in terms of host orientation in biting flies in general and the suitability of CST-type traps as components of attractant-based control strategies and in simuliid population monitoring.

Cryptolestes ferrugineus (Stephens) and C. pusillus (Schönherr) were reared separately at initial densities of 20 or 40 adults each and together at an initial density of 20 adults/100 g cracked wheat or cracked maize at 35, 30, 25, and 20°C and 70% r.h. for developmental periods of 10, 11, 16, or 40 weeks, respectively. Intraspecific competition in the 40-adult treatments restricted population growth to levels similar to 20-adult treatments for each species; impact was greatest for C. pusillus on maize at 30°, where the population of the 40-adult treatment was less than half that of the 20-adult treatment. Both species produced larger populations on wheat than on maize, except for C. pusillus at 35°C; mortality for both species was high on wheat at 35°C. Interspecific competition resulted in significantly reduced populations relative to single species populations for both C. ferrugineus at 30, 25, and 20°C and C. pusillus at 35, 30, and 25°C on wheat and for C. ferrugineus at 25 and 20°C and C. pusillus at 35, 30, and 25°C on maize. During interspecific competition, C. ferrugineus was more successful in multiplying at 35 and 30°C on wheat and 35°C on maize; both species multiplied equally well at 25°C on wheat or 30 and 25°C on maize; C. pusillus multiplied best at 20°C on both wheat and maize. Cryptolestes pusillus reproduces more effectively alone or in interspecific competition under cool conditions, although C. ferrugineus occurs with much greater frequency in cool Canadian stored grain, probably because of cold-hardiness and winter survival

Adult flies from five taxa (Bactrocera carambolae Drew & Hancock (formerly ‘Malaysian A’), B. dorsalis (Hendel) sensu stricto, B. melastomatos Drew & Hancock, B. papayae Drew & Hancock (formerly ‘Malaysian B’) and B. propinqua (Hardy & Adachi) of the Bactrocera dorsalis complex were analysed at 17 enzyme loci using horizontal starch-gel electrophoresis. Eleven loci—aAdh, Ald, Gpd, Ldh, aMdh, cMdh, Me, Pgm, Pgd, Sod-F, Sod-S—were represented by the most common allele in the five taxa. Of these 11 loci, seven showed intraspecific variation in one or more taxa. Among the five taxa, B. melastomatos could be distinguished from the rest by two loci (Acp and Gpi), while B. propinqua could be separated by four loci (Acp, Est-D, Idh90, Pep-C). Bactrocera dorsalis, B. carambolae and B. papayae did not possess any species-characteristic locus/allele, but B. carambolae could be distinguished from the other two taxa by Idh. The proportion of polymorphic loci in the Malaysian taxa ranged from 0.41 to 0.53. Bactrocera propinqua had the lowest average heterozygosity (H=0.05), while that in B. carambolae, B. melastomatos and B. papayae ranged from 0.09 to 0.11. The genetic identity values indicate closest affinity between B. dorsalis and B. papayae (I=0.99), followed by B. caramboiae (I=0.92), B. melastomatos (I=0.84) and B. propinqua (I=0.69). Bactrocera melastomatos showed closest affinity to B. carambolae (I=0.87) and was most distant from B. propinqua (I=0.64).

Responses of adult flea beetles Longitarsus jacobaeae (Waterhouse), to signals from ragwort plants (Senecio jacobaea Linnaeus) were studied by recording their directions of movement in a wind tunnel and their colonization of host-plants in the field. Starved beetle individuals, irrespective of gender, orientated toward upwind host-plants over a distance of 60 cm in the wind tunnel, whereas satiated beetles did not. In the absence of upwind host-plants, all beetles moved randomly in all directions, regardless of whether they were starved or satiated. Starved beetle individuals did not show directed movement towards hosts when plants were downwind in the wind tunnel, nor when in the presence of host-plants when the wind was absent. Groups of starved beetles orientated to upwind host-plants in the wind tunnel, as did individual beetles. In the field, plants over 60 cm upwind of the released beetles were found and colonized by more beetles than downwind plants, in spite of the presence of background vegetation. This confirms the result of laboratory experiments that L. jacobaeae can orient to upwind host-plants.