Indicators of diversity (population density, relative number of species and evenness) in ground beetles (Carabidae) and rove beetles (Staphylinidae) in upland rice fields were assessed between 1995 and 1999 at Garoua in the Benue valley in North Cameroon. A total of 4369 beetles belonging to 45 carabid species and 2109 beetles belonging to 31 staphylinid species were caught in pitfall traps. Among the carabid beetles, five species Scarites (Orientolobus) lucidus strigiceps Quedenfeldt, Chlaeniostenus denticulatus elatus (Erichson), Lissauchenius venator (LaFerté), Pheropsophus marginatus (Dejean) and Abacetus crenulatus Dejean, in decreasing order, were dominant. In the staphylinid group, Paederus sabaeus Erichson was the most common, followed by Stenus ravus Puthz and Stenus (Mendicus) senegalensis Bernhauer. The Shannon–Weiner and evenness indices varied slightly from year to year. Diversity values remained relatively low among the staphylinid beetles, revealing that rice fields were underpopulated by this group of polyphagous predators. The features of predatory soil-surface beetles and the role they play as an IPM component in West African rice ecosystems are discussed.

Factors stimulating host seeking behaviour of Eocanthecona furcellata (Wolff), a pentatomid predator, were investigated by using Spodoptera litura (Lepidoptera: Noctuidae) as prey. Faeces of S. litura larvae elicited a host seeking response by the predators. The active material is present in the prey mandibular gland secretions, digestive tract and body surface, which when placed on a filter paper evoked feeding attempts. Predators responded intensely towards the prey artificial diet too. Prey body washings with hexane and acetone also stimulated feeding behaviour.

Physical stimuli such as host shape or movement had no influence on acceptability of the prey to the predator. Larval size correlated with aggressive behaviour which limited predation rather than releasing stimulus for the host acceptance behaviour. Pharate instar stage of the prey was never accepted by E. furcellata. But pupal, egg and adult stages of S. litura stimulated predators to certain extent.

Neither extirpation of antennae nor blinding the vision prevented the bugs from locating the prey. However, excision of rostral tip decreased the prey capture efficiency. It is suggested that the rostral tip contains chemotactile sensillae which are responsible for the prey detection.

The most important cotton pests in Egypt are the Egyptian cotton leafworm, Spodoptera littoralis, and the pink bollworm, Pectinophora gossypiella, together with localized infestations of spiny bollworm, Earias insulana.

Control of S. littoralis is achieved by the hand collection of egg-masses every 3 days during the early part of the cotton season by teams of children. Alternative control techniques currently being investigated include the use of microbial pesticides and insect growth regulators.

Large scale commercial applications of slow-release pheromone formulations are used to control P. gossypiella by the mating disruption technique as an alternative to four or five sprays of conventional pesticides. Similar pheromone formulations are being developed for control of E. insulana, which occurs towards the end of the cotton season.

As a result of using such a combination of selective control methods, beneficial insect populations have remained at high levels throughout the season and acceptable levels of infestation have been achieved associated with relatively few applications of conventional pesticides.

Sorghum, maize and cowpea serve as staple food for people in Africa and are grown mostly by small-scale farmers. A major constraint on the production of these crops is attack by insect pests among which crop borers are most important, causing 30–80% yield losses. Use of pesticides to control these pests is hazardous and not feasible for the farmers. Alternative strategies for the integrated pest management (IPM) are being developed at the International Centre of Insect Physiology and Ecology (ICIPE) and include the following components: (1) Intercropping and other cultural practices, (2) Plant resistance to insect pests, and (3) Biological control. These IPM components have now been developed to a stage where they can be taken for on-farm trials under farmers' management for subsequent use by them. But, adoption and diffusion of agricultural innovations requires a prior knowledge of the farming systems and the socio-economic circumstances in which the target farmers operate, and their bearing on the use of innovations. Information on these aspects has therefore been obtained through a survey of farming households in Kendu Bay and Oyugis Divisions in western Kenya during April—August 1986. The survey was conducted jointly with UNECA and Ministry of Agriculture, Kenya, under a project funded by the Royal Government of Belgium.

The survey involved interview with 150 farmers, (75 in each Division. In Kendu Bay 27 were men and 48 women whereas in Oyugis 40 were men and 35 women.) and was based on a questionnaire which comprised six sections. Five sections covered the farmers' background, farming practices, pest problems and their control, socio-economic conditions, and accessibility/willingness of the farmers to participate in the project. The last section included field observations on the insect pests of sorghum, maize and cowpea.

On the basis of the information obtained on above-mentioned aspects, criteria were defined and assigned appropriate weigh tage for selecting 25 farmers in each Division for on-farm trials. The selected farmers included 12 men and 13 women in Kendu Bay while in Oyugis 13 men and 12 women were selected.

The measures that need to be taken to counter these limitations and thereby assist the farmers in increasing food production have been recommended.

Chitinases are found in species from all kingdoms, including Kingdom Animalia. We purified chitinase, poly [1,4-(N-acetyl-β-d-glucosaminide)] glycanohydrolase, by cation exchange chromatography on SP-Sepharose from the integument of a lepidopteran, the Mediterranean flour moth, Ephestia kuehniella Zeller, and further characterized it. Ephestia kuehniella chitinase has similar properties to other insect chitinases, with respect to the molecular mass. Its molecular mass was 79.7 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature for activity were 6 and 40 °C, respectively. The purified enzyme exhibited stability at a pH range from 4.5 to 8.0 and showed high sensitivity to Co2+, Mn2+, Ca2+, Hg2+ and Ag+. The Km and Vmax values of E. kuehniella chitinase were, respectively, 3.98 mg/mL and 7.11 μmol/min/mg for colloidal chitin. In comparison to the values determined for the substrate affinity, the enzyme had a 2.36-fold higher affinity for Carboxymethyl–Chitin–Remazol Brilliant Violet (CM–Chitin–RBV) as a soluble substrate. We examined the antibacterial effect of E. kuehniella chitinase on the growth of both Gram-positive and Gram-negative bacteria. The enzyme inhibited the growth of Bacillus subtilis, Bacillus thuringiensis and Escherichia coli, where the average diameter of inhibition zone was 20, 23 and 19 mm, respectively. The antimicrobial effect and chitinase activity strengthen the hypothesis that the enzyme could be used in biological control against plant pests.

Most germplasm lines and improved sorghum genotypes identified as resistant to shoot fly (Atherigona soccata Rond.), stem borer (Chilo partellus Swin.), midge (Contarinia sorghicola Coq.) and head bugs (Calocoris angustatus Leth.) are resistant to only one of these insects which usually will infest the same crop during the same season. At ICRISAT Center, India, a technique was developed in which entries were subjected to an array of combinations of pest infestations for identifying and separating genotypes with resistance to one or more insects.

Using this technique, 220 resistance sources and breeding lines were evaluated for multiple insect resistance. Less than 10% of shoot fly resistance sources had acceptable resistance (< 3 on a scale of 1–9) to shoot fly, but over 50% showed good resistance (scores of 1–3) to stem borer. IS 18551 and IS 2195 were the best entries with resistance to both shoot fly and stem borer. However, the majority (80–90%) of shoot fly and stem borer resistant sources were highly susceptible to midge with scores > 8. Similarly, all midge resistant sources were highly susceptible to shoot fly but less so to stem borer where seven midge lines had scores < 5. IS 22464 was the best midge line with a score of 3 for stem borer resistance. Advanced breeding lines showed a wider range of resistance to shoot fly, stem borer and midge with a higher frequency for resistance to stem borer, PS 28060−3 and PM 14388−1 were the most promising breeding lines.

Investigations have been made to evaluate the development of Spodoptera littoralis as affected by feeding on a standard artificial diet containing powder of some plant species known to be resistant to the infestation of this insect. Trials were also made to find out whether the effect of these plants facilitate the potency of Bacillus thuringiensis var entomocidus HD-635 vs. the target insect. The results revealed that powders of pomegranate peel, guava leaves and lemon grass, greatly affected the insect development in terms of larval duration, larval and pupal weights, deformities in pupae and moths, percentage of emergence, egg production and hatching. This may be correlated to the chemical constituents of these plants. A marked increase was observed in the potency of B. thuringiensis endotoxin preparation vs. S. littoralis when combined with some of the tested powdered plants or its extracts but in varying degrees.

Cassava is one of the most important staple crops in Ghana. Losses from the cassava mealybug (CM), Phenacoccus manihoti, and cassava green mite (CGM), Mononychellus tanajoa, infestations in 1983 were estimated at 0.8 m metric tons of tubers. An integrated control programme with biological control playing a key role has been established within the Plant Protection and Quarantine Unit of the Ministry of Agriculture. Of the five beneficial insect species released, only the parasitoid, Epidinocarsis lopezi has so far been established against the CM over the greater part of Ghana. Damage caused by the CM has been reduced quite remarkably, largely due to E. lopezi, with local beneficial insects playing some contributory role. The activity of hyperparasitoids is high and reduces the overall efficiency of E. lopezi.

The effect of CGM is prominent now, perhaps because of the reduction in CM. Exotic phytoseiid mite species were released but no establishment could be documented.

Storage method encompasses the patterns and periods of storage as well as particular storage techniques. Storage management is therefore a major determinant of post-harvest losses in stored cereals: affecting the magnitude of losses and their susceptibility to reduction. Key issues are the location and scale of grain storage which, in most developing countries, involves both rural domestic storage and larger seal “buffer” storage at district centres, commonly near towns.

Various storage techniques are described and discussed against the background of available informatio on storage losses and with regard to the common patterns and periods of storage in Africa at the farr level and in “centralized” storage. The importance of long-term development planning for cereal crop production and utilization is stressed as a major factor in storage pest management and the reduction of storage losses.

The handling of imported food grains is discussed with regard to storage management problems arising from moisture content/relative humidity equilibria as affected by grain temperature.

Greenhouse studies were conducted by artificially infesting potted rice plants with first instar larvae of Maliarpha separatella and Sesamia botanephaga Tarns and Bowden at two stages of plant growth, namely: early tillering stage and at the booting stage. Early infestation by M. separatella resulted in reduction of plant height and the number of filled grains. At the booting stage, the number of filled grains and their weight were higher in uninfested plants. Infestation by S. botanephaga at both stages of plant growth mainly affected the number of productive tillers. Grain weight was unaffected. Field studies on individual hills gave erratic results and there were instances when hills containing tillers bored by M. separatella produced higher yields than unattacked hills.

The behaviour of shootfly resistance is examined over the Fl, F2, F3 and advanced generations. The Fl is almost intermediate between two parents with an added heterotic advantage of a lower ‘dead-heart’ percentage. Resistance shows partial dominance under low to moderate shootfly infestation but this relationship may shift under heavy infestation conditions.

The resistance is polygenic in nature and governed by additive genes. In the absence of host immunity, gradual accumulation of favourable genes is possible by line breeding from R × I and I × I crosses by selecting 1 SD below the population mean. Selection for multiple characters limits the genetic advance for shootfly resistance—resulting in 0- 5% selection intensity and relatively less resistant but high yielding desirable progenies. Multilocation tests enable the selection of varieties stable for shootfly resistance.

Between May 1984 and December 1985, the population of immature stages of Anopheles arabiensis was sampled by the dip method at sites close to two villages in Mwea Irrigation Scheme, Kenya. Larval presence corresponded to rainy seasons and the flooding phase of the rice cycle. No larvae were found during the postharvest dry season. The instar composition, age distribution and survivorship curves for the different stages were determined. Pupal productivity for Mwea rice fields was estimated to be 1% of the total immature population.

Investigations on storage insects infesting stored groundnuts was carried out in farms, markets, stores and out-door storage sites in order to find out the source of infestation. Farm samples were found to be free from infestation. Freshly harvested groundnuts that were just stacked into pyramids were also free from infestation. However, groundnuts stacked into pyramids at central storage areas of Kano and Gusau were highly infested following a year of storage. Groundnuts from stores and markets were moderately infested. The most abundant and widely distributed insect pests were Tribolium castaneum (Herbst) and Oryzaephilus mercator (Fauvel). Ephestia cautella (Wlk.) constituted less than 1% of insect pests found on the groundnuts, but Plodia interpunctella (Herbst) was absent in out-door pyramid storage.

Groundnuts kept in in-door storage had high moisture content, while nuts from farm and open air pyramid storage had low moisture content. Lipid, peroxide and free fatty acid (F.F.A) values from groundnuts were directly related to the levels of infestation.

The predacious mite, Cydnodromella negevi (Swirski & Amitai) completed life cycle when fed on the tetranychid mites Eutetranychus orientalis (Klein), Tetranychus urticae Koch and pollen grains of Ricinus communis (L.) as an alternative food substance in the laboratory. The duration of the immature stages and adult stage were determined. Immature stages of C. negevi consumed in total an average of 27 E. orientalis and 34 T. urticae, whereas each day throughout her life, the adult female consumed an average of 11 of E. orientalis and T. urticae. While feeding on these prey, C. negevi laid 1.3 and 1.0 eggs per day. The number of eggs deposited per day increased (3.3 eggs/female/day) when fed on eriophyid mites. Females neither fed nor reproduced on liquid nutrients.

To develop management strategies for the mango seed weevil (Sternochetus mangiferae), we surveyed infestation levels of the pest in three agroecological zones of Benin and determined the influences of abiotic factors on mango infestation levels and population dynamics in mango orchards at IITA-Benin from 2009 to 2011. We collected immature and mature fruits from the canopy and fallen fruits from under the canopy from three randomly selected trees per cultivar, per orchard. Samples were examined to determine the number of the mango seed weevil eggs to adults during the rainy seasons of three years of the study. Our results show that the highest abundance of both the weevil and its eggs was from March to May of each year. In the first year of sampling, the cultivar Eldon was more infested than the other two cultivars, while during the second and third years, the cultivar Alphonse was most infested. The occurrence of the weevil was almost nil in the hot agroecological zones, while for the mango cultivars of IITA-Benin the percentage of infested fruit increased or decreased according to the studied variables, such as temperature, rainfall, and relative humidity. We found that the period from March to May with low temperatures and high rainfall was favourable to the population increase of mango seed weevils. We discuss possible implications of our findings for the management of the pest.

Reserpine (a pharmacological agent of plant origin) injected into females of Glossina morsitans morsitans was highly effective in preventing ovulation when injected 1–2 days before the egg is normally ovulated. In contrast, reserpine was only modestly effective in blocking parturition, thus suggesting that these two closely related temporal events may be independently regulated. Males injected with reserpine frequently initiated copulation, but sperm and accessory reproductive gland secretions were never transferred to the female. Reserpine, which presumably acts by depleting stores of amines in the nervous system, may have considerable utility in probing the neuroendocrine regulation of tsetse reproduction.

The larval critical weight (Lcw) in the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) was 54.6 ± 1.0 mg for average sized male and female final instar larvae and was 63 and 39% of the larval maximum weight (Lmw) of males and females, respectively. There was a consistent decrease in weight from Lmw to pupal weight of 35% in both males and females over successive generations of rearing two laboratory populations. The adult weight was consistently about 37 and 22% lower than the pupal weight for males and females, respectively. During starvation, 25% of the final instar larvae produced a supernumerary moult. A positive correlation was derived between female pupal weight and fecundity. The results were similar to those derived from a study on the progeny of a wild population. A model representing the various fresh weight changes in relation to the Lmw has been suggested for this species. The model is similar to that proposed for other Lepidoptera. The results of this study are largely consistent with those carried out on other species of Lepidoptera and underline the value of using stable standards in assessing the quality of laboratory reared insects.

Plastic dishes 30 cm dia. and 15 cm depth filled with water as traps for Tropinota squalida Scop, adults and painted blue, green, red, white and yellow were exposed in infested peach areas at Abo-Sultan during 1987–1988. Traps painted blue showed high degrees of attractancy to the pest. White, yellow and green attracted the least number of beetles while red was found to have no attraction. Trapping is considerably influenced by microecological conditions, trap placement and trap diameter. Blue traps (25) were sufficient to suppress the pest population in an infested peach area. Blue trap could be considered as a new forecasting method and for studying the swarming dynamics of T. squalida adults.

For the last three years, CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement, France) and the University of Pretoria led field research to evaluate the impact of transgenic Bt cotton, expressing the Cry1Ac toxin, on arthropod biodiversity in South Africa. The diversity and the density of insect populations were estimated at different crop development stages using traps, sweep-nets, and direct observations on the cotton plants. In untreated plots, the insect diversity in Bt cotton did not show major changes. The toxin was efficient in controlling one of the major bollworm species, Helicoverpa armigera (Hübner), and reduced the population density of specific larval parasitoids. Predators were present in comparable numbers in both cotton types, except for ladybirds. The toxin did not affect pollinators. In small-scale farming fields, where pesticides are still sprayed for controlling sucking insects, the introduction of Bt cotton did not help meet the expected reduction in insecticide use.