Seventy cultivare of sorghum representing recently released varieties, hybrids, experimental varieties, lines bred for stalk-borer resistance and local resistant stocks were tested for stalk-borer resistance under artificial infestation during monsoon (July–October) season. There were significant differences among varieties for leaf-feeding injury, per cent ‘dead hearts’, number of holes and tunnels and per cent tunnelling. Released hybrids and local varieties were susceptible for different parameters. Thirteen varieties viz., SPV Nos. 35, 103, 107, 110, 135, 140, 192, 229, E 302, E 304, P 37, R 133 and CSV-8R were at par with resistant varieties for per cent tunnelling per plant. Long peduncle varieties were relatively susceptible.

Leaf-feeding injury, per cent ‘dead hearts’ and tunnelling parameters were not significantly correlated and independent of each and none of them could be related to grain yield. Number of holes, number of tunnels and per cent tunnelling were positively correlated. Thus, number of holes per plant or internode may be a good indicator of per cent tunnelling and can conveniently be used as a criterion for evaluating germplasm to stalk-borer (Chilo partellus Swin.) resistance. The varieties CSV-8R, SPV-35, SPV-103, SPV-140 and SPV-192 were identified as promising sources of resistance to stalk-borer.

Pyramidal traps (8000) have been set up against Glossina fuscipes fuscipes to control Trypanosoma rhodesiense in Busoga. In order to understand the pattern of tsetse/human contact, the collection of data on the density, spatial distribution and mobility of flies has been related to the dynamics of human trypanosomiasis in Busoga. As for T. gambiense, few reasonable correlations between global fly densities and incidence of the disease have been found. However, field observation with a recording time of seasonal variations of movements of people and animals associated with particular habitats, remains the key to understanding the transmission of the disease.

The effect of visual and olfactory stimuli from leaves of two maize cultivars, Basilocal (susceptible) and Kisan (resistant), in eliciting orientational responses by first instar Chilo partellus (Swinhoe) larvae was investigated in the laboratory. The polar and non-polar chemical constituents of these cultivars were extracted in methanol and hexane, respectively. Orientational preference of the larvae for the leaf whorls and hexane extracts of Basilocal leaves was significantly greater than that for Kisan. The methanol extracts of the two cultivars were, however, equally effective in eliciting larval attraction. These observations imply that the non-polar fraction of maize leaves is more effective than the polar fraction in eliciting larval orientation in C. partellus. Moreover, certain chemicals of Kisan leaves, extractable in hexane, elicited larval repulsion whereas those of Basilocal leaves elicited larval attraction. Identification of the chemicals eliciting attraction or repulsion would be valuable in a management programme for this economically important insect pest of gramineous crops.

Recent studies on the chemical ecology of the desert locust, Schistocerca gregaria, have unravelled a rich and complex system of pheromonal and other semiochemical-mediated communication in this insect. The key pheromones associated with such behavioural processes as social cohesion and communal egg-laying have been characterised. The semiochemical bases of such physiological processes as maturation of solitarious insects before the arrival of seasonal rains, development of gregarious traits in crowded solitarious insects, development of maturation synchrony in gregarious insects, and maternal transfer of gregarious characters to the offspring are better understood. Desert locust semiochemicals are finding two principal uses: as tools for studying the processes associated with gregarisation and, therefore, for elucidating the eco-physiological mechanisms underlying the development of locust outbreaks; and as agents for interfering or reversing the process of gregarisation. The status of this research and its implication for the development of novel ecologically friendly tactics for the management of different locust species are highlighted.

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.

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.

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.

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.

The parasitoids Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) and Eupelmus vuilleti Crwf. (Hymenoptera: Eupelmidae) develop mainly on relatively old larvae and pupae of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) found in cowpea seeds. Therefore, it is possible to consider biological control against C. maculatus using these natural enemies. The intrinsic rates of increase for C. maculatus and the two parasitoids were determined during the dry season in the sub-humid area of Bobo-Dioulasso, Burkina Faso, from January to July 1995. Functional response was also analysed for D. basalis and E. vuilleti. At the beginning of the dry season, the cowpea weevil and both its natural enemy species had limited intrinsic rates of increase, attributed to the relatively low temperatures and low relative humidity thatprevail during this period. In March, when temperature and relative humidity began to rise, conditions were optimum for their reproduction and development. Dinarmus basalis showed the higher intrinsic rates of increase and parasitism through the study period. Analysis of the functional response revealed that fecundity and potential for parasitism of both parasitoids were density-related and varied with climatic conditions. However, D. basalis showed a more efficient response. This study has shown that the variations of climatic conditions such as temperature and relative humidity during the dry season significantly influence the development and reproduction of C. maculatus and its parasitoids. Dinarmus basalis appeared to be the better biological agent in controlling C. maculatus.

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.

The intensity of diapause of field-collected diapausing larvae of Olilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Pyralidae) was compared in the laboratory at 28 ± 0.5°C under a photoperiod of 12:12 (L:D)h. Chilo partellus terminated diapause faster than C. orichalcociliellus. Mean time to diapause termination was 9.7 days for C. partellus and 14.4 days for C. orichalcociliellus. Male and female C. partellus larvae terminated diapause and adults emerged at the same time, while significant differences were found in diapause termination and in emergence times between male and female C. orichalcociliellus.

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.

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.

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.

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.

The African armyworm is a migrant moth which, in its larval form, can cause severe plagues which destroy cereal crops, sugarcane and pastures in many parts of Africa. This paper reviews the relevant aspects of a multidisciplinary study into the dispersal behaviour and re-concentration of moths, migratory flight, source areas, population upsurges and the seasonal movement of moths. It introduces the new concepts of primary and critical outbreaks.

Patterns of stemborer life history and the foraging patterns exhibited by a taxonomically diverse array of stemborer parasites are described. Foraging strategies provide functional descriptions of natural parasite groupings and include elements of the guild concept plus ecological, behavioural, and morphological adaptations that enable a parasite to locate and exploit a particular host effectively. Elements of the foraging strategy include: host stage attacked, microhabitat of the host, cues employed to locate and identify the host, and method of host attack. Possible constraints presented by the crop plants to the success of different foraging strategies exhibited by groups of parasites are explored.

An additive effect was obtained after treatment of Spodoptera littoralis (Boisd.) larvae with a combination of Bacillus thuringiensis and nuclear polyhedrosis virus (NPVs). The NPVs was the more pathogenic followed by B. t., cytopathologically. Simultaneous application of B. t. and NPVs affected the midgut cells by causing a very specific appearance of cell hypertrophy with some deposits of B. t. crystals on the fourth day of infection as shown by scanning electron microscopy. Transmission electron microscopy showed that the vegetative cells and spores of B. t. entered the midgut epithelial cells followed by the virus. It is possible that the initial destruction caused by the B. t. toxin facilitated penetration and entry of the virus.

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.