The fall armyworm, Spodoptera frugiperda (J. E. Smith), has a high reproductive rate of 900–1000 eggs per female, a relatively short generation time of 30 days and good dispersal ability. These traits make it a successful colonizing species. There is a large body of circumstantial evidence that migration is a major component in the life history strategy of this species. Although the fall armyworm is unable to survive the winter in the United States except in southern areas of Florida and Texas, it redistributes itself over most of the eastern United States each growing season. Long-range movement from Mississippi to Canada in 30 hr on a low-level jet stream was documented on one occasion with synoptic weather maps. Many fall armyworm moths have been collected in the Gulf of Mexico as far as 250 km from land, indicating the possibility of seasonal trans-Gulf migration between the United States and the tropics. Electrophoretic analyses of populations of a corn “race” of fall armyworm collected throughout the Caribbean Basin indicated low genetic heterogeneity. Nei's genetic distance estimate (0.015) and Wright's Fst value (0.032) both suggested undifferentiated populations with interbreeding across the entire geographic range. Wet and dry seasons in the east and west coast of Central America and elsewhere in the tropics alternate with each other so that only one habitat is available at a time. This fluctuation in available habitat is proposed as the templet that led to the evolution and maintenance of migration in the colonizing life history strategy of the fall armyworm.

Food security is a problem in many developing and less developed countries due to increase in human population and decrease in crop productivity and food availability. Edible insects are a natural renewable resource of food providing carbohydrates, proteins, fats, minerals and vitamins. As such, entomophagy is common in ethnic groups in South America, Mexico, Africa and Asia, where indigenous insects are easily available and are consumed in various forms (raw/processed) or used as an ingredient or supplement in modern recipes. Entomophagy therefore offers an opportunity to bridge the protein gap of human foods irrespective of a few constraints that are discussed. Concerning food security, more attention is needed to assess and revalidate entomophagy in the context of modern life. Further research would be necessary to exploit insect biodiversity and ethno-entomophagy, stop overexploitation of these insects, and initiate actions for insect conservation.

Data on insects as food in sub-Saharan Africa were collected by reviewing the literature and conducting interviews in a number of African countries. A list of about 250 edible insect species from Africa was compiled. Of these, 78 percent are Lepidoptera (30%), Orthoptera (29%) and Coleoptera (19%), and 22 percent Isoptera, Homoptera, Hymenoptera, Heteroptera, Diptera and Odonota. Insects are rich in protein, vitamins and minerals, and a good source of iron and B-vitamins. Examples of insects being toxic are given, but often traditional methods are used to remove the poison. Whether or not insects are eaten depends not only on taste and nutritional value, but also on customs, ethnic preferences or prohibitions. The harvesting of insects is often done by women. The way of collecting depends on insects' behaviour. For example, inactivity at low temperatures enables easy catching of locusts and grasshoppers in the morning. Night flyers (termites, some grasshoppers) can be lured into traps by light and some insects like palm weevils can be attracted to artificially created breeding sites. Some species (crickets, cicadas) can be located by the sound they make. A number of tools are used to facilitate capturing such as glue, sticks, nets and baskets. Because most insects are only seasonally available, preservation by drying is often practised. Some examples of how to prepare them as food are given from important insect groups.

To manage insects in the interest of food security more attention should be given to environmentally sustainable harvesting methods. They should be made better available throughout the year by developing improved conservation methods or by farming this minilivestock. Considering the economic, nutritional and ecological advantages of this traditional food source, its promotion deserves more attention both from national governments and assistance programmes.

A new fruit fly species suspected to be from the Bactrocera dorsalis (Hendel) group (originating from Asia), was detected during routine field surveys in the Coast Province of Kenya. Since most species in this group are of tremendous quarantine concern when introduced, and considering the fact that it has never before been detected or reported in continental Africa, surveys were immediately initiated covering a distance of over 3000 km across major fruit-growing and trading localities within Kenya, to determine the extent of spread of the new invasive species. We report on the detection of the flies, preliminary results of the survey, and discuss the potential effects of these flies on the horticulture industry in East Africa.

This review concentrates on air-borne chemical cues that blood-seeking mosquitoes use to locate a host. A distinction is made between short- and long-range attraction. Carbon dioxide is involved in both processes. It activates and attracts mosquitoes. The latter function is only observed in combination with an odorous organo-chemical. Other olfactory cues are primarily involved in long-range attraction. Bodily emanations from the host that contain olfactory cues can be divided into three groups: Skin emanations, exhaled air and urine. Each of these is attractive to mosquitoes, but there is little knowledge about the chemical compounds that cause the attraction. Lactic acid in the presence of CO2 is attractive, and lactic acid-sensitive neurosensilla are present on the antennae. Other host-produced chemicals are also attractive, but chemical identification and subsequent confirmation of attractiveness for mosquitoes has not been reported. Host preference in mosquitoes is species-specific and varies from highly specific to opportunistic. Attraction is likely to be caused by a mixture of several compounds. Synergism may be an important way of increasing the effect of separate chemical cues.

The purpose of this study was to investigate nutritional and phytochemical composition of Henicus whellani Chopard, a seasonally occurring ground-dwelling cricket consumed in south-eastern Zimbabwe. Insects were sampled from four quadrants (approximately 100 m2) in one representative site (approximately 3000 m2) in Bikita District, and were hand-picked or dug out from burrows in a manner similar to traditional insect-harvesting practices. Proximate composition using whole-dried insects and bioactive components using dried pulverized material were analysed using standard procedures. The proportional nutrient composition was 53.6% crude protein, 4.3% fat, 13.4% ash, 10.6% crude fibre, 4.0% carbohydrate and 268.3 kcal/100 g energy. Phenolics, tannins, alkaloids, cyanogenic glycosides, oxalates, saponins and flavonoids were present in the extracts of insects. The quantities of saponins (53.3 mg/g) and alkaloids (52.3 mg/g) were higher than those of other phytochemicals, with the quantity of tannins (0.168 mg/g) being the lowest. Radical-scavenging capacity determined using di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (or 2,2-diphenylpicrylhydrazyl) and methanol extracts was 42%, which is lower than those of the standards. This study shows that H. whellani provides potential nutritional benefits in terms of protein, fibre and flavonoid contents. The relatively high ash content compared with that from other edible insects indicates a rich source of minerals such as calcium, iron, magnesium, phosphorus and potassium. However, the presence of saponins, oxalates and tannins could be a limitation and requires further studies. There is a need to evaluate the bioaccessibility of the nutrients and the safety of bioactive compounds in relation to human consumption.

The effect of phenolic compounds on the preference for winter wheat cultivars as hosts by cereal aphids and the effect of the phenolics, reported in the leaves of cereals, on feeding intensity of Rhopalosiphum padi (L.) larvae was investigated. Preference for the studied winter wheat cultivars was associated with the level of phenolic compounds naturally occurring in the plants. The tested dihydroxyphenols showed highest inhibition of the feeding of R. padi larvae.

Allelochemicals from essential oil-bearing plants have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. With an aim to reduce the use of synthetic insecticides, they represent one of the most promising approaches for eco-chemical control of insects. Eight compounds were evaluated via topical application against third instar Chilo partellus Swinhoe larvae. Thymol was the most active (lethal dose (LD)50 = 189.7 μg/larva) and methyl eugenol the least (LD50 = 1069.4 μg/larva). The compounds were also tested at sublethal levels, i.e. LD10 and LD30, and there was approximately 15–43% of reduction in growth, which was transitory, and some recovery was observed 6 days post-treatment. Compounds were also used as binary mixtures and tested for synergy, using toxicity and feeding inhibition parameters. The data showed that thymol and α-terpineol synergized the effects of both linalool and 1,8-cineole, but linalool with 1,8-cineole exhibited only an additive effect against C. partellus. Although there is no specific generalization that could be drawn relating to efficacy of binary mixtures, the present findings resulted in several complex mixtures that could be developed and tested as leads for effective control of C. partellus.

Laboratory studies were carried out to investigate the role of larval habitat-derived microorganisms in the production of semiochemicals for oviposition site selection by Anopheles gambiae Giles sensu stricto mosquitoes. Dual-choice bioassays with gravid females were conducted in standard mosquito cages. Field-collected or laboratory-reared mosquitoes, individually or in groups, were offered a choice between unmodified (water or soil from a natural breeding site) or modified substrates (filtered water, autoclaved soil or sterile media to which bacterial suspensions had been added). Egg counts were used to assess oviposition preferences. Mosquitoes preferred to oviposit on unmodified substrates from natural larval habitats containing live microorganisms rather than on sterilized ones. Variable responses were observed when sterile substrates were inoculated with bacteria isolated from water and soil from natural habitats. We conclude that microbial populations in breeding sites produce volatiles that serve as semiochemicals for gravid An. gambiae. These signals, in conjunction with other (non-olfactory) chemical and physical cues, may be used by the female to assess the suitability of potential larval habitats in order to maximize the fitness of her offspring.

The composition and preparation of a general purpose artificial diet for rearing insects is described. Forty-one species were reared for one generation or more, and 56 species were partially reared or maintained on this diet. The advantages and applications of using a single diet for multiple-species rearing are described.

The diet is economical (NZ $2.37 per kg) for general laboratory rearing. In freeze-dried form it can be used for bioassays of pathogens, pesticides, insect growth regulators, plant resistant chemicals and other toxins, and has a potential market in the development of insect rearing kitsets for educational purposes.

The sensory receptors on the antennal flagellar segments and on the rostral tip of four adult hemipteran insects were identified and compared using scanning electron microscopy in order to better understand the role of sensillae in the process of host plant selection and the structural adaptations of feeding organs for phytophagy. The species studied are Riptortus pedestris Fabricius (Alydidae), Elasmolomus sordidus (Fabricius) (Lygaeidae), Cyclopelta siccifolia Westwood (Pentatomidae) and Chrysocoris purpurea (Westwood) (Pentatomidae). Differences in the distribution and arrangement of sensory receptors in the hemipteran families were noted, especially in the shape of the antennal apices, which are of taxonomical significance. A large array of trichoid basiconic and coeloconic sensillae is distributed on the antennal surface. Distal antennal segments have more sensillae and more types of sensillae than the proximal segments, indicating their prominent role in host plant surface exploration. There is only a slight variation in the shape of the stylets owing to the similarity in feeding habits. The mandibular tips are straight and sharp and do not contain any hooks or barbs as in carnivorous species.

Recording of electroantennographic (EAG) responses from tsetse, Glossina pallidipes and G. morsitans morsitans (Diptera: Glossinidae) has been used to detect olfactory stimulants in volatiles from cattle. The most potent stimulant in cattle odours collected on Porapak resin has been identifiedas 1-octen-3-ol by gas chromatographic retention data and mass spectrometry. The rate of production of 1-octen-3-ol by a normal ox was estimated to be 0.043 mghr−1, and the natural material was shown to be predominantly the (R)-(−)enantiomer. No 1-octen-3-ol was collected under the conditions used in the absence of an ox. EAG dose-response curves to 1-octen-3-ol showed it to be about 106 times more potent than acetone, a known attractant for tsetse, with the maximum response of about 1 mV occurring to approx. 1 ng at source. 1-octen-3-ol caused increased upwind flight by tsetse in a wind tunnel bioassay, and in the field it was attractive to tsetse by itself and also increased the attractiveness of both ox odour and of mixtures ofcarbon dioxide and acetone.

Maize is the principal food and cash crop for millions of people in the predominantly mixed crop-livestock farming systems in Kenya. Stemborers and striga (Striga hermonthica) are major constraints to increased maize production in eastern Africa. An intercropping and trap crop system has been developed, using a ‘push-pull’ strategy, for the control of stemborers in small scale maize farming systems. The ‘push-pull’ strategy involves trapping stemborers on highly susceptible trap plants (pull) and driving them away from the crop using repellent intercrops (push). Napier grass (Pennisetum purpureum Schumach) and Sudan grass (Sorghum vulgare sudanense Stapf.) are used as trap plants, whereas molasses grass (Melinis minutiflora Beauv.) and two species of desmodium (Desmodium uncinatum Jacq. and Desmodium intortum Urb.) repel ovipositing stemborers. The integrated ‘push-pull’ strategies were shown to increase parasitism of stemborers through attraction of parasitoids to one of the intercrops, molasses grass. The leguminous intercrop, silver leaf desmodium, drastically reduced damage to maize by the parasitic weed, striga. This aspect was further investigated and developed for integration with stemborer control. On-farm trials with farmers in Kenya have shown significant yield increases in maize farming.

The Asian citrus psyllid Diaphorina citri Kuwayama is a destructive insect pest in citriculture, because it is an efficient vector of the proteobacteria ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. africanus’ (Laf) and ‘Ca. L. americanus’ (Lam). These bacteria cause the ‘huanglongbing’ disease or ‘greening’ or ‘yellow dragon’ disease. The disease kills the plant and reduces fruit production. This insect pest is susceptible to entomopathogenic fungi, and we report the use of different strains of Metarhizium anisopliae, Cordyceps bassiana and Isaria fumosorosea against the nymphs and adults of D. citri under field conditions. The fungi were applied four times using a concentration of 2 × 1013 conidia/ha with a time interval of 15 days between applications. The percentage of control of Cb 108, Ma 65, Ma 14 and Ifr 4 was 60, 50, 40 and 35% in nymphs, and 50, 50, 42 and 22% in adults, respectively. Metarhizium anisopliae, C. bassiana and I. fumosorosea applied on Persian lime groves are more effective in reducing higher density of nymphs than adults of D. citri.

Maize was artificially infested with either 10 or 25 individual Prostephanus truncatus (Horn) and Sitophilus zeamais (Motschulsky) or a mixture of both, and stored in a hermetic grain bag (HGB) or a woven polypropylene bag (WPB) for 150 days. Population growth of P. truncatus and S. zeamais during storage was low in HGB, while in WPB, the insect population increased significantly with storage duration. Mortality rate during storage was significantly higher in HGB than in WPB. After 60 days of storage, the average mortality rate of 99.50% was observed in HGB infested with 25 P. truncatus, and 100% for S. zeamais at the same infestation density after 90 days of storage. Grain losses were significantly lower in HGB compared with WPB. Less than 0.5 and 6.0% losses were obtained, respectively, for S. zeamais and P. truncatus in HGB infested with 25 individual insects after 150 days of storage, whereas losses of 19.2% (infestation with S. zeamais) and 27.1% (infestation with P. truncatus) were observed in WPB. HGB seems to be resistant to the perforation of S. zeamais, but not to P. truncatus. The moisture content of maize grains stored in HGB remained practically the same during storage, compared with the levels in WPB, which reduced with storage time. WPB could be used for maize storage, protecting it against insect infestation without the need for insecticide use.

An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit flies in the northern savannah ecology of Ghana. Fruit samples from 80 potential host plants (wild and cultivated) were collected and incubated for fly emergence; 65 (81.5%) of the plant species were positive to fruit flies. From records in Africa, 11 plant species were reported to be new hosts to the African invader fly, Bactrocera invadens (Drew, Tsuruta and White, 2005). This study documented the first records of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation by B. invadens was higher in the cultivated fruits; Ceratitis cosyra dominated in most wild fruits. Cucurbitaceae were mainly infested by three species of Dacus and Bactroceracucurbitae, a specialized cucurbit feeder. Among the commercial fruit species, the highest infestations were observed in mango, tomato, sweet pepper and watermelon, whereas marula plum, soursop, tropical almond, sycamore fig, African peach, shea nut, persimmon, icacina and albarillo dominated the wild host flora. The widespread availability of host plants and the incidence of diverse fly species in the ecology call for particular attention to their impact on commercial fruits and the development of sustainable management strategies against these economically important pests in Ghana.

The amino acid, fatty acid and mineral composition of Aspongubus viduatus F. (melon bug) and Agonoscelis pubescens (Thunberg) (sorghum bug) were investigated. The approximate analyses of A. viduatus and A. pubescens adults showed 8.3 and 7.6% moisture, 27.0 and 28.2% crude protein, 54.2 and 57.3% fat and 3.5 and 2.5% ash on a dry-matter basis, respectively. The bug protein contained 16 amino acids, including all of the essential ones. Compared with the amino acid profile recommended by FAO/WHO, the protein was of medium quality. The most predominant fatty acids in melon bug oil were oleic, palmitic, linoleic and linolenic acids, viz. 45.5, 31.3, 4.9 and 0.48%, respectively, and in sorghum bug 41.15, 11.41, 35.28 and 1.28%, respectively. The mineral analysis indicated high P and K content. Scanning electron microscopy was used to study ground insect structure before and after oil extraction. Micrographs of full-fat ground insects were different from defatted ones.

This paper is an attempt to synthesize information available on C. p. quinquefasciatus in Africa. The latter is presently found in most urban areas of the African continent and in rural settlements which show some trends towards urbanization. In East Africa, and the islands of the Indian Ocean, C. p. quinquefasciatus is one of the major natural vectors of Wuchereria bancrofti. In addition it can also transmit, under laboratory conditions, some other pathogenic agents.

Preimaginal forms develop in different kinds of man-made breeding-places, especially those containing polluted water. The situation in each African region is reviewed in detail.

Female behaviour during the different phases of the gonotrophic cycle is analysed, together with population dynamics.

Control methods by synthetic insecticides are discussed in relation to resistance problems and the characteristics of the breeding sites. Other control methods based on the use of growth regulators, genetic manipulation, biological agents (parasites and predators) and environmental management have been investigated as well. Most of them cannot be easily applied or are not yet applicable for control operations.

Aggregation pheromones have been identified and tested in the field for Frankliniella occidentalis and Thrips palmi. These pheromones are produced by adult males and attract both males and females. They are likely to be widespread across the Thripidae and identification is in progress for several other pest species. Aggregation pheromones are used commercially for monitoring and activation. Field trials have shown they can be cost effective for mass trapping when used as part of an integrated pest management (IPM) programme. Use for other approaches, such as lure and kill and mating disruption have not yet been tested. A better understanding of the role of these pheromones in the mating behaviour of thrips is needed and this may suggest further ways of developing their potential for pest management.

Toxicity and antifeedant activity of crude seed extracts of Annona squamosa (Magnoliales: Annonaceae) from Maluku, Indonesia, against the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) and the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) were determined using different bioassays. Aqueous seed extracts and an aqueous emulsion of ethanolic seed extracts were toxic to both species. Crude aqueous extract also deterred feeding of fourth-instar P. xylostella in a leaf disc choice bioassay. Toxicities of crude aqueous extracts to natural enemies, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Orius insidiosus (Say) (Hemiptera: Anthocoridae) were investigated using direct spray and residual contact tests. Chrysoperla carnea larvae were less susceptible to the extracts than were O. insidiosus adults.