Since its humble beginnings in the late 1990s, use of the sterile insect technique (SIT) in South African crop agriculture evolved from an underfunded ‘rag and bones’ operation in Stellenbosch for a single pest, Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), on deciduous fruit and table grapes, to privatized programmes for three fruit pests, viz. Medfly, false codling moth (Thaumatotibia leucotreta (Meyrick)) on citrus, and codling moth (Cydia pomonella (Linnaeus)) on apples and pears.Afourth SIT programme, for the sugarcane stalkborers, Eldana saccharina Walker and Chilo sacchariphagus Bojer, is well under development. This review focuses mainly on the Medfly SIT programme, but gives brief summaries of the development and current status of SIT for the other pests mentioned. However, many of the hardships experienced by the Medfly SIT programme have also been experienced by those people that developed, or are still developing SIT for the other pests. During the last 15 years the Medfly programme has passed through many phases and evoked many emotions, including hope, despair, misunderstanding and mistrust; but it also bred perseverance, determination, empowerment and, later, confidence. It has also included an international DNA investigation to identify the origin of a Medfly outbreak in the SIT area. The Medfly SIT programme started at Agricultural Research Council (ARC) Infruitec-Nietvoorbij in Stellenbosch in the Western Cape Province with a feasibility study over some 5000 ha of table grapes in theHex RiverValley area, releasing by air 5 million sterile male Medflies per week, produced in a run-down outbuilding with questionable equipment. Fungal rot, ant invasions, severe rust, lack of funding, inexperience and ignorance were among the challenges. The feasibility project subsequently metamorphosed into a fully-fledged, privatized programme which now produces 25 million sterile male Medflies per week in a modern, state-of-the-art facility with high-specification equipment and highly qualified technicians, distributed weekly to three different production areas and released on the ground. The current objective of the Medfly SIT programme is population suppression, but this is merely a means to an end. Medfly is regarded as a pest of international quarantine importance, and a number of countries impose strict phytosanitary measures against this pest. The ultimate goal, therefore, is the creation of Medfly-free areas, leading to sustained and expanded international fruit markets without trade restrictions due to Medfly. Many challenges still remain, but there is a fierce determination by those involved that it will succeed. In the meantime, the false codling moth SIT programme, based in Citrusdal in the Western Cape Province, is very successful and has improved and expanded significantly. The pilot release phase of the sugarcane borer SIT programme is expected to be fast-tracked after the likely procurement of an irradiator in KwaZulu-Natal in 2015. However, for economic and other reasons the codling moth SIT programme had to be terminated in 2014. ‘Will SIT in South Africa fly?’ It is already flying, but it needs to fly much higher. With the necessity to export fruit from pest-free areas, to minimize crop losses of commercial and small-scale farmers, and considering the large investments already made in SIT in South Africa, there should be no going back.

Control of arthropod pests on indigenous flower crops often has particular challenges. Here we investigate the arthropod species associated with indigenous cultivated Protea species and cultivars in the Cape Floristic Region (CFR), South Africa. Arthropod individuals were collected from various commercial varieties of protea as well as from wild protea plants. Arthropod individuals were recorded directly on plants in the field (for disturbance-sensitive species), as well as from specific plant parts carefully enclosed in plastic bags and taken to the laboratory. Of the arthropod morphospecies recorded, 95.9 % were insects, and the rest mostly mites. A total of 37 % of the individuals could be identified to species level, along with 33 new species records of arthropods on protea plants. Taxonomically, Coleoptera, Lepidoptera, Hymenoptera and Diptera were the most abundant and speciose groups. Structurally complex plants and mixed stands of plant species harboured the most arthropod species. Morphospecies were sorted into guilds, as determined by previous studies. In general, guild structure reflected the complexity of structure of individual plants as well as the mixture of plant species and cultivars, with apparently strong natural enemy activity on complex plants and mixed groups. The free-living, flower visitor guild was the most abundant, with largely beetles contributing to this guild. Endophages were about equal in abundance across all cultivars but less on those with simple structures. From rank abundance curves, a total of 30 % of the arthropod species were categorized as abundant, with the rest (70 %) being rare. Most species were generalists on the various proteas, with some being species or cultivar specialists. A total of 7.26 % species recorded were major pests affecting commercial production of proteas in the CFR. This protea agroecosystem, being composed of plant types being grown in their general native area, resulted in about 93%of the arthropod species being restricted to the Proteaceae, with only 5.6%associated with other South African crops. Even though some of this arthropod assemblage is adverse for protea farming in theCFR, these commercial fields are nevertheless playing a role in biodiversity conservation in the fynbos. The wild proteas supported only intermediate arthropod abundance, suggesting strong, and probably complex, natural regulatory processes at work.

Pseudonoorda edulis Maes & Poligui (Lepidoptera: Crambidae), the safou red borer caterpillar (SRBC), is a new insect species from Central and West Africa, recently reported as a fruit pest of Dacryodes edulis in Gabon. Damage in Gabon was estimated at 22 % in terms of fruit loss. Two peaks of attacks were recorded at the end of September and November, respectively. Fully grown larvae were red and the moth was earthen in colour. Average length and breadth of eggs were 0.86 ± 0.01 mm and 0.47 ± 0.01 mm, respectively. First, second, third, fourth and fifth instar larvae measured in length as 4.80 ± 0.09 mm, 8.00 ± 0.12 mm, 13.03 ± 0.32 mm, 15.17 ± 0.08 mm and 19.69 ± 0.43 mm and in breadth as 0.87 ± 0.02 mm, 1.87 ± 0.02 mm, 2.30 ± 0.32 mm, 2.67 ± 0.03 mm and 2.75 ± 0.21 mm, respectively. The male and female wingspan average was 19.64 ± 1.05 mm and 22.60 ± 1.40 mm, respectively. Further investigations are needed to assess suitable strategies for biological control of this pest.

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) is known to be the most serious pest of coconut palms and other cultivated palms in India, South Asia, North Africa, Europe, the United States and the Middle East. The larval feeding sites of the date fruit-stalk borer (FSB), Oryctes elegans Prell, may be attractive to RPW to lay eggs. Understanding the correlation between the RPW and FSB might help in predicting RPW infestations. The relative abundances of both species were followed in 16 date-palm production orchards in the Kingdom of Saudi Arabia from June 2007 to May 2008. A specifically designed light trap was used to monitor FSB, and pheromone traps (ferrugineol (4-methyl-5-nonanol)) were used to monitor RPWs. There was a weak correlation between FSB abundance and subsequent RPW infestation in date palms (R² = 0.0039). The relative abundances of both species were well synchronized in the date palm orchards that were sampled.

Eighteen sesame varieties were tested in the field for their responses to major insect pests with or without insecticide application. Insect pest density was higher in the unsprayed plots than the sprayed plots, except Myzus persicae whose density was significantly higher in the sprayed plots. Lower insect density was recorded on Yobe-Chambamba, while higher pest density was recorded on Domu, in late season. Yobe-Chambamba and Eva were not attacked by M. persicae. Leaf and capsule damage were significantly lower (2 % each) on Yobe-Chambamba.Amongthe varieties,Yobe-Chambambacarried the least pest population intensity, while highest pest density was recorded on Domu, NCRIBEN-01M, Yobe-gadaka, 530-6-1, Cross-95, E-8, PB-Til, Ciano-16 and Cameroun white. Lambda-cyhalothrin application significantly reduced pest density in the early season but not capsule damage or any of the plant characteristics measured. The use of lambda-cyhalothrin may not be necessary for the control of insect pests on sesame in the experimental area.

Voltinism is an important life history trait that varies with the environment. In temperate zones, insect populations take a substantially longer time to reach the adult stage in the northern compared to the southern regions. In this study, emergence pattern and larval growth of the threatened zygopteran (Odonata) Coenagrion mercuriale were investigated in a population located in the southern limit of its distribution range in order to determine its life history strategies in a hot climate and compare them to those displayed in northern populations. There was no apparent winter diapause. The species produced two generations in a year, with the first generation emerging in mid spring and the second in late summer. The emergence pattern of the first generation was typical of a summer species and lasted 48 days. All larvae emerged by the end of May. Due to some environmental perturbations, the emergence pattern of the second generation was not surveyed, but there was evidence that the emergence season was short (21 days). Larval structure prior to the second emergence of the year showed that only 25%of the population was in the final instar, which explains the shorter emergence season.We assume that the first eggs laid in the spring hatch and grow rapidly to reach the final instar in late summer as a consequence of higher temperatures and potential high food availability. There was a significant seasonal decline in body size in both males and females. The second generation had a significantly smaller body size, presumably due to the short growth season and/or higher growth rate.

The white coffee stemborer, Monochamus leuconotus (Pascoe, 1869) (Coleoptera: Cerambycidae), is a key insect pest of Arabica coffee, Coffea arabica in Africa. We tested the effect of C. arabica varieties and stem treatment by wrapping, smoothening and insecticidebanding on the incidence of this pest and yield of the crop. The pest incidence was consistently lower on C. arabica variety KP423 than on two other varieties KP162 and SL28, suggesting that KP423 is less susceptible to M. leuconotus. Correspondingly, KP423 yielded almost five-fold more coffee cherries than the other two varieties. Stem-smoothening and insecticide-banding did not significantly influence the incidence of M. leuconotus, while stemwrapping occasionally increased the incidence of the pest. None of the stem treatments influenced the yield of coffee cherries. These results support cultivation of KP423 in areas prone to M. leuconotus, and offer prospects for identification of resistance genes against the pest. The results, however, contradict previous reports that stem-smoothening and stem-wrapping can suppress M. leuconotus.

The objective of this study was to evaluate the ability of two Beauveria bassiana isolates and one Paecilomyces sp. isolate to infect Nezara viridula adults under laboratory conditions. The lethal concentrations (LC₅₀) of the Egyptian and exotic Beauveria and Paecilomyces isolates for N. viridula were 323 × 10⁶, 835 × 10⁶ and 281 × 10⁷ conidia/ml, respectively. Although, there was no significant difference observed in the mortality rates of adults exposed to the conidiospores of the fungal isolates, the results demonstrated a concentration-dependent pattern. The conidia showed limited attachment to the insect integument. Interestingly, a positive relationship was observed between the rate of increase in the germination of conidia and that of the exposure time, up to 84–92 % at 48 h post-infection. Furthermore, germination of the isolates on the wings was significantly different. The conidia gave rise to germ tubes at 12 h with bipolar germ tubes and hyphal network at 48 h post-infection. SEM revealed that the Egyptian Beauveria strain damaged both the epicuticle and procuticle at 72 h post-infection with tube penetration in the cuticle and epidermis of both the exotic Beauveria- and Paecilomyces-infected bugs. Many changes were recorded in the cuticular phenoloxidase, fatty acids and hydrocarbons following fungal infection. These results induce direct relationship between the changes in the cuticular composition and the attachment/ germination of the entomopathogenic fungi. These data provide useful information with regard to the applicability of entomopathogenic fungi against N. viridula.

Two adult food supplements, namely 10 % solutions of honey and sugar, were tested to evaluate the reproductive potential of the pteromalid parasitoid, Dinarmus basalis, on Callosobruchus chinensis (L.). Distilled water was fed as untreated control. The highest adult longevity was found when fed with 10 % honey solution (male 19.3 ± 0.68, female 27.9 ± 0.81 days) while the lowest was recorded when fed with distilled water (male 14.4±0.80, female 19.7±0.57 days). Females produced overall 143.6±0.52, 184.8±0.54 and 211.35±0.57 offspring when fed with water, sugar and honey, respectively. The total fecundities were 194.3±0.60, 245.85±0.63 and 273.9±0.66 per female when fed with water, sugar and honey, respectively. Time of development of the parasitoid was faster when females were fed with honey as compared to other food supplements. Sex ratios indicated that the parasitoid produced female-biased progenies. Dinarmus basalis produced progeny throughout their life sequentially and therefore it is synovigenic. The honey-fed female parasitoids showed the best performance with increased fecundity and longevity over the other food supplement.

Essential oils extracted from native aromatic plants are currently considered as promising alternatives to protect stored cowpeas from pests inWest Africa. The optimal application of essential oils has not yet been investigated. One key factor to consider would be the practical considerations of cowpea storage, such as quantity of seeds and type of storage container. For this purpose, we tested the efficacy of essential oils extracted from four native plants in controlling Callosobruchus maculatus, the major pest of stored cowpeas. First, we evaluated Callosobruchus maculatus mortality rate in relation with increasing amount of cowpeas. Then, experiments were conducted with essential oil in two different materials: plastic and aluminium in order to determine the weevil perforation index, the intrinsic rate of natural increase and the rate of cowpea germination. In fine, aromatized powder mixed with cowpea seeds are used against Callosobruchus maculatus by evaluating the mortality rate. The quantity of seeds influenced the efficacy of pure Lippia multiflora and Hyptis spicigera essential oils, whereas essential oils from Ocimum americanum and Hyptis suaveolens were not affected by stock size. The type of storage device used influenced the effectiveness of essential oils tested, plastic containers being more suitable than aluminium ones. Ocimum americanum used as contact insecticide in different aromatized powders exhibited variable toxic effects on C. maculatus.We conclude that essential oils appear to be safe alternatives to insecticides for long-duration storage of cowpeas.

Periodical and age-related variation in female calling, sex pheromone titres, and male responsiveness were studied in the legume pod borer, Maruca vitrata. The results showed that females initiated calling on the first night after eclosion and called mainly on the third to fifth hour during scotophase. The percentage of calling increased from 1- to 3-day-old females and decreased from 3- to 5-day-old females. The quantification of the hexane extracts of pheromone glands by gas chromatography (GC) revealed that the titre of (E,E)-10,12-hexadecadienal (E10E12-16Ald), in pheromone glands was well synchronized with female calling at different ages. The titre of the primary sex pheromone component peaked at the fourth hour into the scotophase. The sensitivity of male antenna to primary sex pheromone E10E12-16Ald (10 ng/µl) varied considerably with age, but no time-dependent difference in electroantennographic responses was found. The temporal pattern of male M. vitrata responding to sex pheromone gland extracts in the wind tunnel demonstrated that males became sexually mature on the third night, which also paralleled the calling activity of females. This study indicated that there existed distinct periodical variations in female calling, titre of the primary sex pheromone component, and male responsiveness in Maruca vitrata during scotophase. These three parameters were well synchronous and age-dependent.

Female Aedes aegypti mosquitoes are vectors of yellow fever, dengue and chikungunya viruses. Pre-exposure of Ae. aegypti larvae to the herbicide atrazine significantly reduced their sensitivity to the organophosphate insecticide temephos. Mosquito larvae pre-exposed for 48 h to non-lethal concentrations of atrazine ranging from 1 to 10 μg/l commonly encountered in the field, appeared slightly less sensitive to temephos than non-pre-exposed larvae. The effect of a pre-exposure to atrazine on larval tolerance to temephos did not seem to be related to an induction of detoxification processes by this herbicide.Noimportant increase in glutathione transferase, or α- and β-esterase activities was observed in pre-exposed larvae, while P450 monooxygenase activities increased.

The exotic parasitoid, Phaedrotoma scabriventris Nixon, was imported from Peru for the biological control of invasive Liriomyza species in vegetable and ornamental crops in Kenya where Opius dissitus Muesebeck is the most abundant indigenous Liriomyza parasitoid. Both species are solitary larva-pupal endoparasioids attacking the same larval stage. In order to assess whether these two species compete or co-exist, an interaction study involving sole, sequential and simultaneous releases of the two species on polyphagous Liriomyza huidobrensis (Blanchard) was conducted in the laboratory at the International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya. Simultaneous releases of 50 individuals each of the two parasitoids resulted in significantly higher total parasitism rate (61.96±4.60) than in the single release of P. scabriventris (34.94±8.50). Simultaneous release of 25 individuals of each species resulted in a parasitism rate (44.52 ± 2.75) similar to that obtained for single releases of 50 individuals of O. dissitus (42.57 ± 3.35) and P. scabriventris (34.94 ± 8.50). No significant effect was observed in total parasitism between sequential and single releases of 50 individuals of each species. The specific parasitism rate of each parasitoid species in the simultaneous release of 50 individuals of each species was not significantly different from when each species was released alone. The first introduced parasitoid in sequential releases achieved the same parasitism rate as when released alone. However, the second released species gave a significantly lower parasitism rate than when released alone and compared to the first released species. The F1 progeny sex ratio was balanced for P. scabriventris but male-biased inO. dissitus. The sex ratios of both parasitoid species were not significantly affected, neither in simultaneous nor sequential releases, except in one of the sequential release where P. scabriventris was released second, with its sex ratio significantly female-biased. Non-reproductive host mortality was not important for both parasitoids when used alone and in combined releases compared to the natural mortality observed in the control. These findings suggest that P. scabriventris has no detrimental effect onO. dissitus and its release into Kenya's agricultural ecosystems will enhance the management of Liriomyza leafminer.

The genus Culicoides Latreille is represented by 160 described species in the Afrotropical Region; of these, approximately 10 % are plain-wing species, the wing lacking a distinctive pattern of pale and dark spots. This plain-wing sector includes C. walkeri Boorman which, till now, has been known only in the female, based on nine specimens fromKenya. The hitherto unknown male of C. walkeri is described here (and the female redescribed) based on material collected in South Africa since 1970. Culicoides walkeri can be distinguished from other plain-wing species in its pale ochreous colour, the robust shape of the male genitalia, and the sensilla coeloconica distribution which, uniquely, is the same in both sexes (occurring on flagellomeres 1–12). Though the feeding habits of C. walkeri are not known, its greatly inflated third palpal segment and the copious number of sensilla found on the flagellum, indicate it to be ornithophilic. Culicoides walkeri would appear to be confined to the frost-free savannas of the eastern length of Africa, from the equator southwards; its limited distribution in South Africa is mapped and shows that this uncommon species is confined to the Central Bushveld, the Lowveld and the Mopane bioregions. We propose that C. walkeri remain unplaced to subgenus.

The blue gum chalcid, Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) is an invasive pest in Eucalyptus plantations in the world. Low temperature is one of the most important factors influencing the invasion and colonization of L. invasa. However, effects of diel temperature fluctuations (e.g. rapid cold-hardening (RCH)) on survival of L. invasa are less well understood. Here, we investigated the survival and differentially expressed proteins of L. invasa adults' response to different pre-treatment protocols. Survival of adults exposed at -20 °C decreased from 100 % (0 min and 15 min) to 5 ± 2 % (45 min). Survival of L. invasa adults, exposed at -20 °C for 45 min, was the highest at the pre-treatment temperature of 4 °C for 90 min. Mass spectrometry analysis and database searching helped us to identify a total of 85 proteins that exhibited differential expression, in which up-regulated expression of 28 proteins and down-regulated expression of 57 proteins were observed in comparison with control. Up-regulated proteins were members of heat shock proteins and ribosomal proteins, while down-regulated proteins were members of energy metabolism and degradation. In conclusion, RCH could enhance the cold hardiness of L. invasa adults.Theadaptive responsemayallow L. invasa to invade the extreme environment in the world.

Senecio madagascariensis Poir. (Asteraceae), which is native to southern Africa, has invaded agricultural lands in several countries, reducing pastoral productivity and poisoning livestock. Severe infestations in Australia and Hawaii have prompted investigations into the feasibility of biological control. Surveys in KwaZulu-Natal, South Africa, considered to be the origin of the plants that have invaded Australia and Hawaii, revealed several insect herbivore taxa that attack the plant's floral and structural tissues. However, their potential as candidate agentsmaybe influenced by the extent of their association with the plant throughout the year. Populations of S. madagascariensis around Pietermaritzburg were sampled four times over one year (i.e. across seasons) to determine the presence and abundance of the major herbivore taxa relative to the plant's phenology. Similar amounts of foliar and floral material were available to the various insect herbivore guilds throughout the year. The sampled plant populations supported 84 % of the insect herbivore taxa known to be associated with S. madagascariensis in KwaZulu-Natal. Nine of the 10 taxa that were deemed promising as candidate agents were recovered and included three capitulum feeders, four stem borers and two foliage feeders. Of these nine taxa, four were recovered during all four sampling occasions, while two were recovered on three occasions, two on two occasions and one on one occasion only. There were significant differences across seasons in the abundance of these candidate agents. The release of combinations of agents, that attack the same or different tissues, may be required to compensate for differences in abundance and ensure that herbivore pressure is sustained throughout the year.

This investigation demonstrates the influence of the juvenile hormone analogue methoprene, which is an insect growth regulator, on female Helicoverpa armigera adult reproduction and longevity as well as on the development of their F1 progeny. Female moths were treated with different methoprene concentrations (0, 0.1, 1, 5 and 10 µg in 2 µl acetone) on the first day of eclosion. As the methoprene concentration was increased, adult longevity gradually decreased but female fecundity increased greatly. The highest dose (10 µg) did not produce significant effects on female fecundity, but dramatically decreased adult longevity and caused a decline in cumulative survival of F1 immature stages, especially eclosion, but had no significant effects on egg hatch and pupation. The developmental periods of F1 larvae were significantly shortened in 1 and 5 µg methoprene-treated groups. F1 pupal periods had no significant difference among all methoprene-treated groups. The results show that methoprene affects not only reproduction and longevity in the adult but also life-history traits in their F1 progeny.

A number of insects, primarily Lepidoptera, cause damage to citrus in South Africa. A major limitation to the management and control of these pests is their correct identification. The aim of this study was to develop a database of gene sequences to aid in the identification of these Lepidoptera. Multiple specimens of 12 species were sequenced for the ∼650 bp of the cytochrome oxidase I gene. These sequence data were supplemented and validated using sequences available in public databases. Results showed that each species could be unambiguously identified, and neighbour-joining analysis based on K2P distances formed highly supported, distinct clusters for each species, i.e. the maximum intraspecific genetic distance was less than that of the minimum interspecific genetic distances. Thus, this data set provides a molecular means to successfully identify the most important Lepidoptera associated with citrus in South Africa.

A survey of Odonata in streams on Mount Edough, Algeria, and in Kroumiria, Tunisia, indicated strong faunistic similarities between these two areas, characterized by the presence of lotic dragonfly species with protracted larval development such as Aeshna cyanea, Boyeria irene and Onychogomphus uncatus. Climatic oscillations and marine transgressions have isolated these mountains and their North African populations in the past geological times, which have led to distinct adaptations and stenotopy in various zoological and botanical groups. These mountain forests are also a refuge for aestivating Odonata with postponed reproductive maturation like Lestes numidicus, a species new for Tunisia, Lestes barbarus, Sympecma fusca, Aeshna mixta, Sympetrum meridionale and S. striolatum. In the light of increasing human encroachment, urgent conservation efforts are needed to ensure the perpetuity of these unique habitats in North Africa and their biota.

False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is indigenous to sub-Saharan Africa and infests a large number of commercial and wild fruit-bearing plants. The pest was unknown in theWestern Cape Province of South Africa until the end of the 1960s, when it was first identified in fruit orchards in the Paarl region. By the late 1970s T. leucotreta was well established on citrus and other host plants in the Olifants River Valley, approximately 180 km north of Paarl. Since then, control measures for the pest included a small number of insecticides, mating disruption and orchard sanitation. However, a longer termsolution was needed and research on the sterile insect technique was initiated in 2002. This initially involved three phases: a study of the radiation biology and F1 sterility of T. leucotreta (phase 1), field cage experiments (phase 2) and a pilot project over 35 ha of T. leucotreta-susceptible citrus (phase 3). Favourable results in these studies led to the design and construction of T. leucotreta-specific rearing equipment and the building of a massrearing facility capable of producing up to 21 million insects per week (phase 4). Commercial sterile insect releases over 1500 ha of citrus orchards in the Citrusdal region commenced in 2007–08. This area was expanded to 3000 ha in 2008–09 and 4000 hectares in 2009–10 (phase 5). Over the three years the status of T. leucotreta as a pest threat was systematically reduced in the sterile insect release area compared to the non-release area. Feral male populations were reduced 3-, 8- and 10-fold, pre-harvest crop losses decreased by 50 %, 80%and 93 %, and post-harvest export fruit rejections in the SIT area dropped 13 %, 25 % and 38 %, respectively, compared to the non-SIT area.

A review of Fernando Poo's Rhopalocera collection in the Museo Nacional de Ciencias Naturales (MNCN) in Madrid led us identify 172 species (14 Papilionidae, 18 Lycaenidae, 29 Pieridae, 94 Nymphalidae, and 17 Hesperiidae), of which 33 are new records for Bioko Island. To identify certain specimens in the genus Graphium, the genitalia of several individuals selected from among specimens captured on different dates and in various locations were examined and all were unequivocally seen to belong to the species Graphium policenes policenes. Therefore, we consider that the distribution of G. biokoense on Bioko Island should be revised.

The scale insect Aulacaspis yasumatsui is native to Southeast Asia and a major pest of cycad (Cycadales) plants. Due to an increase in worldwide trading of cycads, A. yasumatsui has spread globally and has become a major threat to many cultivated and native cycads worldwide. In this study we report formally, for the first time, A. yasumatsui infesting cycads in South Africa. This scale insect was observed infesting cycads in three provinces in South Africa, namely, Gauteng, KwaZulu-Natal and Limpopo. Its identification was based on morphology and nucleotide sequences of three gene regions. Although more common and damaging on non-native Cycas species, its presence on some native South African Encephalartos species is of concern and effort should be made to control the spread and impact of this pest in the country.

Three chalcidoid wasp species, Megastigmus zebrinus Grissell (Torymidae), Quadrastichodella nova Girault (Eulophidae) and Leprosa milga Kim & La Salle (Eulophidae), have each been described independently as gall inducers associated with Eucalyptus species (Myrtaceae). The finding that at times they emerge together from seed capsules of river red gum (Eucalyptus camaldulensis Dehnhardt) collected at the same site in South Africa, cast doubt on the accuracy of these earlier interpretations. The current study examined the gall inducing abilities of each of the three wasp species. During geographical surveys, all three species coexisted in seed capsules at 16 of the 61 sites sampled. A study of the seasonal emergence pattern of the three species, together with a fourth, locally abundant gall associate, Aprostocetus sp., showed that Q. nova and L. milga emerge during early summer, while the remaining two species emerge in smaller numbers throughout the year. Oviposition trials on sleeved branches of E. camaldulensis, from which all insects had previously been excluded, verified that Q. nova had the ability to induce galls, while both M. zebrinus and L. milga failed to do so. Only one type of gall of characteristic structure was encountered, which repudiates the possibility of a second gall inducer, and no indication of inquilinism was found. Megastigmus zebrinus, L. milga and Aprostocetus sp. are thus more likely to be parasitoids.DNA sequences were obtained for the adults of all four these species. By matching the DNA of identified adults with that of juvenile hymenopterans in the galls, it was confirmed that all four hymenopterans species developed within the seed-capsule galls of E. camaldulensis. Regrettably, this technique failed to give a clear indication of the exact host relationships between the various gall inhabitants. By dissecting seed capsules at different stages of gall development, the origin of the gall was proven to be in the placenta of one of the locules of a flower bud, and not in a seed or ovule, as previously reported.

Azadirachtin, an insect growth disruptor, is known to be an antagonist of the juvenile hormone and 20-hydroxyecdysone (20E). However, its mechanism of action remains to be understood. Furthermore, the effects of the interaction of azadirachtin and 20E have not been investigated. The current study examined the effect of azadirachtin topically applied alone or in combination with 20E on Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). In initial bioassays, various doses (0.5, 1, 1.5, 2.5 and 4.5 µg) of azadirachtin was tested alone on newly ecdysed pupae and the inhibition doses (ID) of adult emergence determined. In a follow-up experiment, azadirachtin applied alone at its ID₂₅ (0.59 µg) and ID50 (1.10 µg) was evaluated on catalase (CAT) and glutathion S-transferase (GST) activities, and yolk protein content in fat body and ovaries. Results showed that azadirachtin at the two tested doses increased significantly the activity of both GST at 48 and 72 hours, and CAT at 24, 48 and 72 hours following treatment. Moreover, azadirachtin treatment at these doses reduced significantly the yolk protein content in fat body and ovaries as compared to the control series. Finally, the exogenous 20E (0.25 and 0.50 µg), applied 24 or 48 h after azadirachtin treatment, relatively restored the normal values of CAT, GST and yolk protein content in fat body and ovaries. All these results indicate that exogenous 20E can compensate the depressive effects induced by azadirachtin on D. melanogaster.