Insect pests are major yield reducers in sorghum under traditional farming practices in Africa. The use of resistant varieties in an integrated pest management scheme provides the most cost effective and practical means of sorghum insect control. Corneous grain sorghums are more weevil resistant than their softer endosperm counterparts. A wide range of sources of resistance to shootfiy, stem-borer and greenbug are known. Breeding for resistance to sorghum insects has been practised with varying degrees of success. Greenbug resistance breeding in sorghum has been successful in the U.S.A. Stem-borers are perhaps the most serious group of sorghum insects in Eastern Africa and further efforts are needed in breeding for resistance to these pests. In an effective pest resistance breeding work, the breeder and the entomologist must work as a team to make the fastest possible progress. Where several pests are of concern in an area, genotypes with multiple resistance in good agronomic backgrounds are needed.

The activities of mankind which introduce excess nutrients and/or pollutants of various kinds into lakes, streams, estuaries, soils and the air, can, and often do, cause significant changes in aquatic and terrestrial environments world-wide. The pollution problem is critical because of the pressures of increasing populations, industrial growth and intensification of agricultural production. Conflicts of interest arise everywhere as challenges to resource use and natural state (‘beauty’) are turned into public issues.

A light trap was operated in Samaru, Nigeria between 1973 and 1980 to monitor populations of Coniesta ignefusalis. Two generations of the insect/year were represented by two adult peaks in July and September. In 1974, an early peak in May resulted in three generations. In cages in the field, eggs were laid between the leaf sheath and the stem in batches of 20 to 70 with a mean of 47.5 eggs/batch. Laboratory studies conducted at 25–28°C and 75–85% r.h. showed an average developmental period of 35.5 days. The average duration of the egg, larval and pupal stages were 4.5, 21.9 and 9.2 days, respectively. Unfed adults lived for 5.3 days.

Field investigations were carried out in northern Nigeria to determine the prominent natural habitats of phlebotomine sandflies. Two biotopes, termite hills and rock crevices, were identified as the major habitats with the termite hills being the most significant. All the 12 species (Phlebotomus duboscqi, P. rodhaini, Sergentomyia antennula, S. bedfordi, S. africana, S. schwetzi, S. ingrami, S. adleri, S. clydei, S. buxtoni, S. affinis and S. christophersi) identified in this study came from this source. Only a small number of samples representing a few species were collected from the three other habitats (tree holes, animal burrows and a cave) investigated. The distribution of the sandflies was found to be influenced by the availability of suitable biotopes and physico-chemical composition of the soil.

This paper gives an account of the activities of the International Red Locust Control Organisation for Central and Southern Africa (IRLCO-CSA) in the management of the red locust, other locust species and non-locust migratory pests in the 1980s and 1990s. It also analyses the advances made by IRLCO-CSA in implementing a preventive control strategy so as to avoid future plagues and outlines the activities of IRLCO-CSA during periods of locust recession.

There were widespread upsurges throughout the 1980s into the 1990s, with outbreaks being recorded throughout the period 1985–1997. Without doubt, the period 1981 to the present, was the most active since the suppression of the last plague in the 1940s. It is concluded that the threat of red locust plagues is not yet over and that the continued existence of IRLCO-CSA remains key to the food security needs of the region.

The biology of Chilo partellus (Swinhoe) was studied on two resistant, IS 2205, IS 5469 and two susceptible, HC 136, ICSV1 sorghum genotypes. Significant differences were observed between resistant and susceptible genotypes in regards to larval mortality in whorl, larval period, larval weight, larval length, per cent pupation, pupal weight, fecundity per female and total life span of this pest. Growth index was also influenced by the resistant genotypes. It has been concluded that high mortality of larvae on resistant lines is due to antibiosis.

The correlations between the characters of the pest biology have been worked out and larval stage was the most important parameter influencing the total pest survival and population build-up in the succeeding generations.

This study was conducted on both station and farmers' fields during the 2010 dry cropping season in the Vallée du Kou rice scheme. We investigated the effect of three rice-transplanting periods (8–10 days) on the population dynamics, damage and parasitism associated with rice stem borers. The on-station experiment was designed as a randomized complete block with three treatments (planting dates) and four replications. Regular intervals of 14 days were observed between subsequent planting dates. Weekly agronomic and entomological assessments were performed from the 21st day after transplanting (DAT) to the 84th DAT. The on-farm experiment covered 1200 ha divided into two zones in which 48 farmers' fields were selected according to the periods of rice transplanting (resulting in 16 fields per period). On-station results indicated 10.1% of deadhearts and 7.5% of whiteheads due to stem borers in the first transplanting period, resulting in the lowest yield (2 metric tons/ha). In farmers' fields, the genus Chilo was found to be the most injurious rice stem borer in Vallée du Kou. The highest larval parasitism (38.5%) was recorded in the third treatment. These results provide important data that can be used in the development of an integrated management strategy for rice insect pests in Vallée du Kou.

Field experiments at the Msekera Regional Research Station during 1988–1990 and at Masumba (Luangwa Valley) Sub-station during 1989–1990 showed that six groundnut genotypes—ICG.485, ICG.2271, ICG-2306, ICG.5041, ICG.5045 and HyQ (cg) S-10 were distinctly less susceptible to the leafhopper, Empoasca dolichi (Paoli). ICG.2271 also appeared to combine low susceptibility to early leaf spot, Cercospora arachidicola Hori and good yield potential. This genotype as well as ICG.5041 and ICG.5045 also are known to be resistant to thrips and/or termites. The scope for their utilization in exploitation of leafhopper resistance in groundnut improvement programme in Zambia is indicated.

Animals were trapped in Marigat, Baringo District to investigate animal reservoirs of visceral leishmaniasis in an endemic focus of the disease. Several species of rodents, carnivores and reptiles were captured. Specimens of spleen, liver and blood tissues were taken from the animals. The specimens were triturated into sterile saline and then cultured into NNN medium, and some of it injected into hamsters intraperitoneally. Skin biopsies were also taken and cultured in NNN medium. Slide smears of all the tissues taken were made stained with Giemsa stain and examined under the microscope for amastigotes. Four isolates of leishmanial parasites were made from a gerbil and three monitor lizards.

The xerophytic perennial plant, Agave cantala Roxb. was studied for its biological activity on diamondback moth Plutella xylostella (L.). When cabbage leaves treated with acetone extract of A. cantala leaf were fed to the larvae in all instars, the extract was found to be weakly toxic at the highest concentration of 60 mg/ml, but it prolonged the larval and pupal periods, decreased the percentage of adult emergence and adult longevity. The fecundity and egg hatchability of adults emerging from final instar larvae fed with treated leaves decreased significantly. The eggs laid on treated leaves showed reduced hatchability.

Nearly 8 years of intermittent treatments with temephos on the lower Volta River at Senchi Rapids, Ghana, produced no change in the susceptibility of larvae of the S. damnosum complex to temephos [Abate (R)]. In contrast, 14 months of temephos treatment in southern Ivory Coast produced resistance.

This difference can be explained by the relatively weak selection pressure exerted by the intermittent treatments on the Volta River and the frequent changes in the composition of the population as shown by cytotaxonomic identification of the larvae.

The virus Rhabdionvirus oryctes Huger was tried against the root and stem borer of the cashew (Anacardium occidentale L.) in Sri Lanka by pouring a virus suspension into the galleries, releasing virus-infected adults and placing virus-mixed sawdust at the base of the infested stem. Results obtained after several surveys showed that the sawdust technique gave more positive results. The establishment and infection of the virus in the beetle population accounted for a reduction in the beetle damage to the tree in certain pockets of the cashew plantation.

Studies on developmental biology and feeding and ovipositional preferences of the pea leaf miner, Chromatomyia horticola (Goureau), were carried out on 11 varieties of field peas, Pisum sativum L. Two varieties, P-200 and P-402, offered maximum resistance to the development of pea leaf miner by inhibiting growth as both larval and puparial development were prolonged, and adult longevity, survival and fecundity reduced. These varieties were also least preferred for feeding and oviposition. Differences between the moderately resistant HFP-4 and highly susceptible varieties HFP-5, HFP-6, HFP-12, PG-3, RAU-21, RAU-25, RAU-37and T-163 were not well marked, as most of these had a relatively high value for the developmental success index, based on indices for larval-puparial development, adult longevity, survival and fecundity, and were also highly preferred by the ovipositing females. Variety PG-3, though offering some resistance to development, was highly preferred for oviposition. The local variety T-163, was the most susceptible variety, as it had the maximum value for the developmental success index, and was highly preferred by ovipositing females. The physiological basis of resistance in the two pea varieties is suggested to be mainly non-preference and antibiosis.

Observations on the fauna that live in close association with mounds constructed by Cubitermes testaceus (Isoptera: Termitidae) were made in a grassland area of Uganda. Termite nests were systematically excavated and dissected and a careful record of the fauna associated with each was made.

Arthropods belonging to three different classes were recorded in mounds of C. testaceus and with varying degrees of occurrence. They included insects (93%), chilopods (5%) and diplopods (2%). Ants were found to be the commonest insects in the mounds followed by other termites (21%) Coleoptera (9%) and Dictyoptera (1%).

In view of the carnivorous nature of most of the ants recorded, and considering the feeding behaviour observed in the field, it is suggested that they can have considerable effect on C. testaceus populations in the grassland ecosystem at Kaazi.

Injection of antiserum prepared against accessory reproductive gland (ARG) secretions of the male desert locust, Schistocerca gregaria, disrupted the normal growth and function of the ARG complex in sexually maturing adults. Male locusts were injected with either antiserum or normal guinea-pig serum on days 3, 7 and 10 after adult ecdysis. When the injection of ARG antiserum began as early as day 3 of adult development a marked inhibition of ARG growth was accompanied by the suppression of other characteristics of sexual maturation (yellow body coloration and mating behaviour). Inhibition of ARG growth, while significant, was less pronounced when antiserum injections began on day 7 of adult development, and the injected males did not exhibit normal mating behaviour when placed with virgin females. When single antiserum injections were administered on day 10 of adult development, the males still attained their yellow body coloration by day 19 and copulated normally with virgin females, although their ARGs were only equivalent in size to those 13-day-old males.

A questionnaire survey was conducted to find out the information and knowledge of extension workers on thresholds of cotton bollworms, (Helicoverpa armigera and Diparopsis castanea). A sample of 30 extension officers was interviewed in Southern and Central provinces of Zambia. The results showed crucial deficiencies in extension worker's knowledge on thresholds of key pests and their implementation in cotton IPM. More than 60% extension officers were not aware of the basic information and knowledge such as thresholds of cotton bollworms, the recommended time to start scouting (weeks after germination of cotton) and the number of cotton plants to be examined for pest observance in each field. All extension officers indicated a desperate need for more field oriented practical training on thresholds. The recent increase in the incidence of aphids, Aphis gossypii as reported by 50% extension workers is obviously due to calendar sprays of synthetic pyrethroids and the lack of a suitable aphicide in current spray programme. Demonstrations on the practical aspects of thresholds deserve much more attention at college level and also during the in-service training. More co-operation in cotton IPM training for extension officers within Central and Southern Africa is suggested.

Chilo species are the most important stem borers of sugar-cane. They cause heavy losses to sugar-cane crop and continue to suppress yield in the sugar industry. The control of these borer species through insecticides has been difficult as the damaging larvae spend most of their life-cycle within the cane plant. The breeding of borer resistant varieties is an ideal approach for controlling the damage as it does not cost the grower anything extra, is effective at all levels of pest infestation and its effects are cumulative and long lasting in reducing the pest population. Many plant characters such as leaf surface, rind hardness, leaf sheath tightness, fibre content, stalk pith and diameter and plant vigour have been associated with borer resistance. In sugar-cane breeding, the inclusion of borer resistance characters, in addition to many other agronomic characters required of a commercial variety, is rather difficult due to the segregating nature of this plant. Therefore, it is better to use, as parent varieties the few varieties showing marked resistance without knowing the actual reasons of resistance. The joint efforts of sugar-cane breeders and entomologists in production and selection of a large number of seedlings for desired characters can help to solve this problem to a greater extent.

Pyrethrins I and II were extracted from five seasonal Compositae herbs collected from semi-arid and hilly areas of North India. The relative toxicity of natural pyrethrins were evaluated against Mesocyclops leuckarti sensu lato. Based on the LC50 values, the extract of the plants could be arranged as follows: Tagetes minuta > Pulicaria crispa > T. patuia > T. minuta > P. angustifolia.

Observation on natural enemies of the stem-borer complex on sugar-cane in southern Ghana indicated that Descampsina sesamiae Mensil (Diptera:Tachinidae) is the most important larval parasite of Sesamia species. The relative abundance of this tachinid parasite appeared to vary with the rainfall pattern throughout the year and with the phenology of the sugar-cane plant. The rate of parasitism was found to be higher in the outgrowers fields than in the sugar estate's fields. Differences in cultural practices used as well as the type of vegetation bordering the sugar-cane fields, were believed to be responsible for the difference in the rate of parasitism of D. sesamiae on Sesamia species.

The African armyworm, the larva of the night flying moth Spodoptera exempta (Walk.), feeds on young stages of cereal crops, sugar-cane and all types of grasses in some 30 countries of Africa, from Mauritania and Senegal in the north-west to Ethiopia and Somalia in the north-east, and southwards to Namibia and South Africa. Between 1960 and 1982, outbreaks of armyworms were recorded regularly in East Africa during the ‘outbreak season’ between November/December and June/July, often from southern Tanzania towards the north or north-west at monthly intervals. Analysis of occurrence of outbreaks in Tanzania, Kenya and Uganda in the 1971/72–1973/74 seasons, and rainfall records in Tanzania for 1969–1975, showed that the occurrence of armyworms in Tanzania coincided with the onset and northward progression of the rains up to Kenya and Uganda. Additional results from monthly maps, tables, graphs and histograms of armyworm occurrences in administrative units (Districts and Provinces) in Tanzania, Kenya and Uganda for 20 years (1960–1979), showed that the onset, progress and duration of armyworm attacks in all districts and provinces in each country, tend to follow certain geographical patterns which can be monitored through the use of insect traps and Agricultural Extension Services. In this way, coordinated surveillance of priority areas could enable farmers, pastoralists, Plant Protection and Pest Control Units of the Ministries of Agriculture to identify likely areas and periods of armyworm attacks, so that they could organize strategic or emergency control of armyworms with insecticides when the larvae are still young.