The incidence and distribution of the sorghum head bug, Eurystylus oldi Poppius (Heteroptera: Miridae), and other panicle pests of sorghum in research stations and farmers' fields in West and Central Africa (WCA) were assessed from 1985 to 1994. Maximum head bug abundance was observed during the dough stage. Head bug abundance was greater on improved cultivars, while the local guineense sorghums with long glumes were less susceptible, both at the research stations and the farmers' fields. Grain damage was moderate to severe, although farmers were mostly unaware of this insect and its damage potential, because it remains hidden inside the panicle. Sorghum midge (Stenodiplosis sorghicola Coq.) damage was very high on farmer's fields in Burkina Faso, Niger, and Nigeria. The shootfly Atherigona soccata Rond., stemborer Busseola fusca Fuller, grasshoppers, spittle bug Locris rubens Erichson, Campylomma spp., Creontiades pallidus Ramb., Agonoscelis spp., head caterpillars Helicoverpa armigera Hub., Pyroderces simplex Wlsm. and Eublemma gayneri Roths., were other insect pests damaging sorghum in the areas surveyed. It is proposed that future efforts in sorghum improvement for WCA should focus on developing cultivars with resistance to sorghum head bugs.

Food production in Africa is declining, while her population is increasing rapidly. Some factors responsible for low food productivity are mentioned; special attention is given to the problem of agricultural pests. The hazards of overuse of pesticides in developed countries are cited to caution farmers in developing countries from getting drawn into a similar situation when attempting to solve pest problems. Integrated pest management (IPM), which aims to increase food productivity and profitability without endangering the environment, is recommended as a sustainable solution to the pesticide problem. The role of biological control agents, i.e., introduction, augmentation and preservation of natural enemies is emphasized. In developing sustainable agriculture through IPM, the importance of incorporating farmers' traditional methods of farming into an IPM package and of identifying farmers' overriding concerns, is recommended as a prerequisite to the acceptability and success of such packages.

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.

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.

The first report on the entomopathogenic fungi in the tropics dates back to 1853. Despite their variety, little attention has been focused on their incidence on agricultural pests. Studies over the last 20 years in the tropics have revealed that entomogenous fungi (Deuteromycetes and Entomophthorales) may play an important role in natural control of arthropod populations. Therefore, the use of insect pathogenic fungi as pest control agents is promising.

An important consideration in developing an entomopathogenic fungus as a mycoinsecticide is the selection of the correct and well-adapted strain. New techniques in biotechnology will help in developing methodology for mass production and formulations. Other factors which can be considered, and which may be determinants on the potential of insect pathogenic fungi include the environmental conditions and cultural techniques (e.g. intercropping, planting density, irrigation). The cultural techniques can result in change of the environment favourable to the disease.