Insect rearing and its management is a prerequisite in developing IPM packages for various food crops. Insects reared for the development of these packages should be regularly monitored for quality in order to ensure success. This paper describes various methods of rearing followed at the ICIPE in the process of IPM development. The rearing of Chilo partellus is described as an example of large-scale rearing. Steps in the experimental rearing of Busseola fusca are outlined. The rearing of an egg parasitoid, Trichogramma mwanzai is described as a vital technology in the IPM of maize and sorghum. The value of quality control is emphasized using the rearing of the phytoseiid mite, Neoseiulus teke as an example.

Several insect pests are associated with the sorghum crop, but essentially a few are considered key pests. These include shootfly, several species of stem borers, sorghum midge and a complex of head bugs. Other insect pests which are occasionally devastating and sporadic include leaf feeders and defoliators (Lepidoptera of various genera, locusts, grasshoppers, aphids, beetles, etc.) and also several species of head worms and head beetles. A list of 101 insect pests of sorghum occurring in Africa is presented.

The effects of infection by Trypanosoma brucei and DNA virus on the ultrastructure of the salivary gland cells in Glossina pallidipes Austen were investigated. Cytoplasm of uninfected cells contains a dense ribosomal population and rough endopiasmic reticulum, scattered Golgi areas and mitochondria. In infected ceils of salivary glands the ultrastructural integrity of the cytoplasm is profoundly changed due to cellular proliferation giving rise to a stratified epithelium and gland enlargement; cell degeneration characterized by formation of cytoplasmic vacuoles, chromatin margination, disorganization and elimination of cell organelles and gland hypertrophy. The virus particles are found in the nucleoplasm as well as the cytoplasm of cells. The ultrastructural evidence indicates that the virus are largely assembled in nuclei of cells and virions pass through the nuclear membrane. The trypanosomes are found within the degenerating cytoplasm and lumen of the cell.

The implications of the features observed in the infected cells are discussed, and possible suggestions are made regarding alteration of the metabolic functions due to infection.

Pearl millet, Pennisetum glaucum (L.) R. Br. is attacked by over 100 species of insect pests, but only a few of these are of economic importance. The two major ones, the millet stem borer, Coniesta ignefusalis Hampson and the earhead caterpillar Heliocheilus albipunctella de Joannis have been the subject of research in the Sahel during the last decade. The various methods that have been suggested for the control of these species are briefly discussed. Generally, the control strategy adopted by farmers involves the use of cultural operations that will reduce insect damage. There are no control measures that have been developed for farmers. The more scientific methods that have been suggested are the results from research trials and experiments. These have several limitations. Future perspectives and considerations for developing sound and practical farmer-oriented practices are discussed.

The small scale farming communities own and store much of the cereals they produce. Various aspects of the infestation problem encountered with insect pests of stored cereals have been examined to illustrate the current status of the pest. Reduction of food losses could be effected during producer, consumer and export storage. However, effective management of pest species requires thorough knowledge of the biology and the ecosystem they inhabit. The current management strategies directed against these pests have been examined.

The toxic and repellency effects of four plants Chenopodium procerum, Ocimum canum sinus, Tetradentia riparia and Capsicum frutescens were tested on Acanthoscelides obtectus Say and Zabrotes subfasciatus Boheman. The toxic effect was found on leaves of Ocimum canum sinus and Chenopodium procerum Hochst. The four plants tested did not show any repellency effect on the bruchids.

Fourth instar larvae of laboratory-reared, Ctenocephalides felts and Xenopsylla. brasiliensis were exposed to 50% neem seed kernel extract (NSKE) for periods varying from 30 min to 24 hr. Mortality of larvae was observed from exposure periods of 2 hr and above in both species. At 24 hr exposure, 95.3% and 94.7% of C.felis and X. brasiliensis respectively were killed. LT50s were approximately 6 and 10.5 hr for C.felis and X. brasiliensis respectively. It was generally concluded that neem seed kernel extract was potentially larvicidal against the two flea species and that it could be effectively used for controlling the insects by properly dusting the latter's breeding sites with appropriate concentrations of the extract.

Deltamethrin (IR, 3R)-3(2,2-dibromovinyl)-2, 2-dimethylcyclopropane carboxylate of (S)-alpha-cyano-3-phenoxy-benzyl, was observed in the field in Zambia to offer a better residual effect against adult Rhipicephalus appendiculatus of up to 7 days post-treatment during a high infestation pressure period than on organophosphorus (OP) acaricide. A group of 20 cattle sprayed with deltamethrin wash of approximately 0.005 w/v at 14 days intervals carried an average of less than 12 ticks per head by the 7th day post-treatment, whereas two groups of 20 cattle each, dipped weekly in an OP at 0.05% w/v had an average of over 60 ticks per head. In a theileriosis infected area 14 days' treatment with deltamethrin would probably be unsuitable for disease control during high infestation period, but 7–10 days would probably yield better results than those likely to be obtained with OPs.

An experiment to examine the effects of different plant spacings on cowpea insect numbers and yields was undertaken at two sites in Nigeria. Two varieties, viz. Tvx 3236 and IT84E-1-108 were planted under field conditions at three different plant spacings. Plant spacing did not affect the number of Ootheca beetles, pod-borers, flower thrips and pod sucking bugs. Yield differences were not significant for the spacing regimes and there were no interactions between spacings and insect numbers for yields. Thus, plant spacing may not be an important control tactic in the management of the key cowpea insect pests in Nigeria.

Several tsetse control campaigns have been carried out in Senegal. During the 1970s a ground spraying campaign was carried out in the Niayes region (relic of Guinean forest infested with Glossina palpalis gambiensis, Vanderplank, 1949). At the beginning of the 1980s, the chemical control was strengthened by use of screens and biconical traps. As a result no fly has been caught in the region since 1983.

An assessment of the second method, done in Kolda (south of the country), has shown a reduction rate of 98% against G. palpalis gambiensis.

Entomopathogens have been isolated and developed for the control of various lepidopteran, coleopteran, dipteran, hymenopteran, homopteran, and even acarine pests. Among the orthopteran pests, the acridid defoliators are important in Africa, and the periodic outbreaks of the desert locust, Schistocerca gregaria; red locust, Nomadacris septemfasciata;migratory locust, Locusta migratoria migratorioides and brown locust, Locustana pardalina; as well as numerous grasshoppers, cause extensive crop losses. Laboratory and field tests carried out on control of locusts and grasshoppers using microorganisms have shown that there are key candidates which could be used for the management of these acridid pests.