The Ceratitis FARQ species complex consists of four highly destructive agricultural pests of Africa, namely C. fasciventris, C. anonae, C. rosa, and C. quilicii. The members of the complex are considered very closely related and the species limits among them are rather obscure. Their economic significance and the need for developing biological methods for their control makes species identification within the complex an important issue, which has become clear that can only be addressed by multidisciplinary approaches. Chromosomes, both mitotic and polytene, can provide a useful tool for species characterization and phylogenetic inference among closely related dipteran species. In the current study, we present the mitotic karyotype and the polytene chromosomes of C. rosa and C. quilicii together with in situ hybridization data. We performed a comparative cytogenetic analysis among the above two species and C. fasciventris, the only other cytogenetically studied member of the FARQ complex, by comparing the mitotic complement and the banding pattern of the polytene chromosomes of each species to the others, as well as by studying the polytene chromosomes of hybrids between them. Our analysis revealed no detectable chromosomal rearrangements discriminating the three FARQ members studied, confirming their close phylogenetic relationships.

In a bid to develop technologies that serve grower needs for economic management of pests and diseases of hot pepper (scotch bonnet) while protecting public health and the environment, a study to assess the potential of cover cropping and/or less-risk pesticide usage in the management of pests and diseases of hot pepper was conducted for two consecutive seasons in Uganda. A split-plot randomized complete block design with three replications was used with cropping system (main plots) and pesticide treatment (sub-plots) as the factors. There were two cropping systems: the hot pepper+cowpea system vs. a hot pepper monocrop and five pesticide treatment options: (i) prophylactic treatment of plots at transplanting with granular carbofuran; (ii) weekly sprays of a neem-based formulation; (iii) combination of the prophylactic carbofuran treatment and neem; (iv) sulphur sprays at 10-day intervals (season 2 only); and (v) the untreated control. Data were collected on population dynamics of aphids, whiteflies, thrips, mites, nematodes and on plant performance parameters of branching and fruit weight. Results indicated that the hot pepper+cowpea system greatly lowered infestations of aphids and nematodes on hot pepper, but did not decrease thrips and whiteflies; and brought about a yield penalty on hot pepper. Prophylactic applications of carbofuran and/or sprays of a neem-based formulation lowered populations of aphids and whiteflies on hot pepper to varying extents; and increased yield of pepper.

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.

Cowpea, Vigna unguiculata (L.) Walp., is susceptible to a wide spectrum of insect pests from seedling to harvest as well as in storage. Insecticide use has been the most commonly adopted method for the control of cowpea pests. However, due to the deleterious effects of insecticides on man, livestock and the environment, research over the years has been focused mainly on developing resistant/tolerant cultivars as a vital component in the integrated management of cowpea pests. This approach has, however, recorded varying degrees of success, due in part to the multiple and often overlapping pest complex attacking at different phenological growth stages of the crop.

In spite of the progress in the utilisation of insect-resistant cowpea varieties, the use of resistance as a control tactic has by no means been fully realised. There are many important cowpea insect pests for which resistant varieties are not yet available for commercial cultivation. Where resistant varieties are available for a given insect, these varieties may not be widely planted because of their unsuitability to local conditions.

In this paper, the status of host plant resistance research in cowpea is reviewed and some novel approaches aimed at solving its seemingly intractable pest problem are proposed, based on the state-of-the-art scientific and crop biotechnological development. The proposed framework for orientation of cowpea resistance research should ensure yield stability and sustainability for the resource-poor, smallscale farmers in Africa.

In view of the losses of harvested grain incurred due to problems related to storage, marketing, transport, and handling, this paper reviews the situation on storage of food grains in developing countries. It lists the insect pests that frequently attack stored food grains in these countries and discusses strategies that would minimise the damage caused by the pests.

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.

Investigations were conducted on dried fish samples purchased from Faku and Sabo markets (in the Kainji Lake Area) and stored for 6 months. The most abundant insect pest was Dermestes maculatus particularly the larvae. At 3 months of storage, weight losses were 13% for S. galilaeus, 17% for T. niloticus and 19% for Alestes sp. respectively, with the products reduced to powder mixed with insect exuviae and dead larvae. An analysis of the salt content of the samples showed no significant difference between salt composition at the beginning and end of the experiment. A relationship between salt content and the degree of infestation by insect pest could not be established, possibly because of the low percentage salt composition observed on all samples. A suggestion is made as to the possible areas of research to combat the menace of insect pest infestation of dried fish.

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.

Insect pests and plant diseases are among the main factors limiting bean production in Tanzania. A survey of methods of pest and disease management in small-scale bean production systems was carried out in Mgeta Division.

The results revealed that small-scale farmers are well informed of the major insect pests limiting bean production. The farmers know the type of damage caused by most insect species and the time of their occurrence. Although farmers are not aware of the pathogens affecting their crops, they can distinguish damage caused by insects from those due to diseases. Farmers are also aware that diseases are associated with environmental factors which influence disease development.

Farmers use both deliberate practices and incidental practices to manage insect pests and diseases.

The most frequently used deliberate practice is avoidance. Choice of growing season and date of planting are observed closely as a means of avoiding diseases. Although beans are cultivated in both growing seasons (September–December and February–May), the first season is the best for growing beans. Rains are not very heavy, but reliable and well distributed, and the season does not end up with low temperatures and high humidity which favour development of fungal diseases. Planting commences as soon as the rains start because early planted crops suffer less from pests. Farmers do not use purchased inputs in the form of fertilizer and pesticides. Larger insects are killed mechanically.

Incidental control takes place in the form of a number of cultural practices. Intercropping with maize, potatoes, cowpeas, pigeon peas, cassava or sorghum is normal and reduces the risk of crop failure. Terracing, where crop residues and weeds are buried under soil, reduces the amount of initial inoculum of certain pathogens. Farmers use a mixture of seeds of different cultivars deliberately, some high yielding and early maturing; and some late maturing, thus ensuring the farmer of food early in the season and beans as a cash crop later. Such variety mixtures appear to provide a buffer against pests and diseases.

A breeding strategy should be developed for variety mixtures instead of pure line varieties as the productivity of pure varieties in most cases is associated with the use of purchased inputs such as fertilizers and pesticides which are beyond the reach of small-scale farmers. Variety mixtures have a greater efficiency in using environmental resources, and are less affected by pests and diseases, and thus give higher yields than pure varieties.

In the region concerned, agriculture is conducted under stress from several difficult circumstances. These difficulties include, among others, drought, a limited length of growing season, harsh winters, insect pests and diseases, and weeds. The present paper describes several measures that are taken to combat these problems. Control devices include legume green manure/cereal rotations, use of drought-resistant and insect-resistant varieties, and early seeding of spring grain to cause maturation before the period of maximum drought risk. Recently, a wide range of legumes has been grown on a limited basis in the region, and further progress toward improved legume varieties is being pursued.

Maize is the single most important food cereal in eastern and southern Africa. Yield levels, however, are among the lowest in the world. Among the major constraints limiting production are the insect pests. Objective assessment of damage and losses caused by these pests are lacking in several countries within the region. This paper discusses some of the methodologies available, and how they can be used to estimate the losses caused by insect pests under different situations. It emphasizes the need for standardization of the methodologies, so that information generated from different countries can be compared. This will promote collective action to combat the pest menace and increase food security.

Assessment of damage to apparently good quality palm kernels by test insect species under laboratory conditions revealed that all the cultures had other pest species due to hidden infestation. The total damage caused by the insects to palm kernels in the experimental jars ranged from 17.5 to 30.9% at the end of a 1-yr storage period. With the exception of test species, Oryzaephilus mercator (Fauv.) and Tribolium castaneum (Herbst) which were predominant in cultures in which they were formally introduced, the other cultures were found to be dominated by O. mercator, T. castaneum, Lasioderma serricorne (F.) and Cryptolestes ferrugineus (Steph.). Thus the damage reported above was principally due to these four species. Symptoms of damage to palm kernels by O. mercator; T. castaneum and L. serricorne have been given for the first time and the pest status of the beetle pests associated with stored palm kernel assessed relative to damage caused.

Field trials were carried out for two seasons on the effect of insecticides on insect pests, damage and yield of three cowpea cultivars.

During the first season, the preflowering stage of crop growth was found to be infested by Aphis spp, Empoasca spp, Ootheca spp and Epilachna spp, the flowering stage by Megalurothrips sjostedti, Heliothis armigera, Astylus atromaculatus, Coryna kersteni and Mylabris amplectens and the postflowering stage by H. armigera and a number of coreid and pentatomid bugs. Fenthion gave the least protection against pod damage by H. armigera. There were significant increases in the number of harvestable pods per plant with insecticides. There were no significant differences in hull weight and shelling percentage. Grain yield was increased by 96.2 and 109.4% after treatment with dichlorvos and cypermethrin, respectively.

In the second season, cypermethrin and monocrotophos were most effective. Cypermethrin reduced the number of pod-sucking bugs by 58%, H. armigera by 93%, while monocrotophos reduced Empoasca spp by 39% and M. sjostedti by 79%. Cypermethrin reduced damage by pod-sucking bugs by 28%, and by H. armigera by 95%. Monocrotophos reduced damage by pod-sucking bugs by 14%, and by H. armigera by 80%. Significant increases in the number of harvestable pods per plant were obtained with monocrotophos and cypermethrin treatments. There were no significant differences between the number of seeds per pod, and the weight of 1000 seed-grains. Grain yield was increased by 55.4% after both cypermethrin and monocrotophos treatment. The application of these insecticides were financially beneficial but the gain was reduced when six sprays were applied. Cypermethrin and monocrotophos are promising insecticides for controlling insect pests on cowpeas.

Classical biological control has been very effective against many introduced pests in the tropics and because it is permanent should be preferred as a control strategy for these pests. However, many pests are native or long established and of uncertain origin. Although classical biological control of these is more difficult, it has been achieved on a number of occasions but in many instances satisfactory control has not been achieved despite considerable effort. Reassessment of control options is needed for these pests based on more thorough quantitative ecological studies than are available at present. Only in this way will rational control strategies be developed, maximizing the contribution of native as well as exotic natural enemies. Even so, in many instances, control of a complex of pests on a single crop will require development of integrated pest management including, at least initially, chemical control of some pests. For effective implementation, more and better trained personnel will be required as will the active co-operation of farmers.

This paper discusses the effects of some controllable aspects of annual cropping systems on several components of insect pest occurrence. The components of cropping systems include spatial and temporal diversity at the farm level. Some effects of these factors on pest colonisation, numerical increase, emigration, damage, and carryover to future crops are illustrated and discussed. Examples of how cropping systems affect specialist and generalist insect pests are also given. Finally, the effectiveness and practicality of controlling insect pests by manipulating cropping systems is considered. Intercropping appears most likely to reduce insect pest occurrence under general conditions, however the need to manage several different crops simultaneously can present some constraints.