In a sub-Saharan African context, limited natural resources, infectious diseases, including those transmitted by arthropod vectors, and chronic exposure to food contaminated with mycotoxin-producing fungi which, among others, are vectored by insects, are among the major constraints to human health. Thus, pest control should be an important component in human health improvement projects. It appears that the advantages of preventive over curative methods are rarely recognised in Africa, with more emphasis being given to the search for the ‘silver bullet’ than to integrated control approaches. Integrated pest management (IPM) systems can be assigned to different decision-making levels as well as to different integration levels, combining ecological (individual pest species, species communities, species assemblages) and management (crop, cropping systems, farms, communities) levels with the respective control systems. These levels produce a highly structured environment for decision-making, in which the use of modern information technology is important. Case studies show that IPM systems are developed and implemented at four integration levels, whereby most work is done on the lowest integration level, addressing a single pest or pest complex attacking a particular crop, group of livestock or human population, and the respective control measures undertaken. Coordinated efforts to develop and implement supplementary IPM systems at higher levels are concluded to be important elements in integrated pest management and a further contribution to human health improvement and poverty alleviation.

To simplify and improve the effectiveness of human trypanosomosis control efforts as well as reduce their cost, it is desirable to identify high-risk sites for transmission of trypanosomes by tsetse flies to humans. The authors propose a simplification of the risk index previously developed by Laveissière et al. (1994). The simplified index has been developed in Côte d'Ivoire and validated in Cameroon. Unlike the old index which required determination of the flies' daily survival rate, the calculation of this new index requires only the knowledge of the proportions of teneral flies and of flies that have fed on human blood, from the population caught in the various biotopes.

The use pattern of alternative host plants by Maruca vitrata was investigated in southern and central Benin. Among the wild host plants, Pterocarpus santalinoides, Pueraria phaseoloides and Centrosema pubescens were found to be key relay hosts during the long dry season, Lonchocarpus sericeus and L. cyanescens were the most important hosts during the main rainy season, while Tephrosia platycarpa was an essential relay host during the short wet season in between. Cowpea was the major cultivated host plant and can sustain M. vitrata all year round, if available. However, this pest was able to maintain high population levels exclusively on wild hosts without needing to switch to cultivated crops. The relevance of these findings and their implications for the control of M. vitrata are discussed.

The effect of artificial infestation of the spiralling whitefly, Aleurodicus dispersus Russell at 0, 1, 2, 3, 4 and 5 pairs on caged potted pepper (Capsicum spp.) plants at 2 weeks after planting (WAP), representing the nursery stage, and 6 WAP, representing the field stage, was studied in a screen house. Increasing insect density resulted in a corresponding increase in damage to the leaves, measured as leaf drop. Yield reduction was inversely proportional to the whitefly population, with highly significant correlation coefficients. For instance, yield reductions were 8.8 and 36.5% with 1 and 5 pairs of adult whitefly respectively at 2 WAP, and 7.5 and 32.1% with 1 and 5 pairs respectively at 6 WAP. The chlorophyll, sugar, ash, protein and crude fibre contents of the leaves decreased with increases in level of infestation, although infestation had no significant effect on the nutrient contents of the fruits. The significant impact of A dispersus on vegetative growth, yields and chemical contents of leaves confirm it as an economic pest of pepper in Nigeria.

Experiments were conducted to assess the effect of four plant growth regulators (PGRs), namely coumarin, kinetin, gibberellic acid (GA3) and indole-3-acetic acid (IAA), on the development of the melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). All four compounds exerted growth-and development-inhibitory effects on the fly. Coumarin was most potent, followed by kinetin, GA3 and IAA. The first and second instars of the fly were more sensitive than the third instar. Treatment with the PGRs also prolonged the fly's developmental period, reduced percentage emergence and increased percentage of abnormal flies emerging. At the higher concentrations tested (125, 625 and 3125 µg/ml) coumarin, kinetin and GA3 caused 100% mortality in first instars.

The insecticidal and repellent properties of Lantana camara and Tephrosia vogelii were evaluated against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) in stored maize grain. Five treatment rates (1.0, 2.5, 5.0, 7.5 and 10.0% w/w) of each powdered plant material, an untreated control and a synthetic insecticide (Actellic Super™ 2% dust) were used to investigate treatment efficacy on mortality of the adult insect (five to eight days old), F1 progeny emergence and repellency against S. zeamais adults. After 21 days, L. camara and T. vogelii caused 82.7–90.0% and 85.0–93.7% insect mortality, respectively. The mean lethal exposure times (LT50) to achieve 50% mortality varied from five to six days (7.5–10.0% w/w) to seven to eight days (2.5–5.0% w/w) for both plants. Probit regression analysis showed a significant relationship between plant powder concentration and insect mortality. The plant powders and synthetic insecticide reduced adult F1 insects by more than 75% compared to the untreated control. Tephrosia vogelii was most repellent to S. zeamais at 7.5–10.0% (w/ w), repelling 87.5% of the insects, followed by T. vogelii at 2.5% w/w and L. camara at 10% w/w which repelled 65.0 and 62.5% of insects respectively. The implications of these results are discussed in the context of smallscale farmer usage of these plants for stored product protection.

Cerconota anonella is the most important pest of the Annonaceae in the Neotropical region for larval damage, which can result in 60 to 100% losses in fruit production. However information on the pest's biology is scarce. This research compared different artificial diets for rearing C. anonella under laboratory conditions (25.0 ± 1.0 °C; 60 ± 5.0% RH and 14 h photophase). Five diets were compared: A (bean, soybean meal, wheatgerm, casein and yeast), B (maize flour, wheatgerm and yeast), C (wheatgerm and casein), D (wheatgerm and soybean) and E (wheatgerm and soybean). In diet E, the amount of wheatgerm was higher than that in dietD. The results indicated that diet E was the most suitable one for the development of C. anonella.

Adult pale morphs of an aphidophagous lady beetle, Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae), were reared on a non-insect diet for periods ranging from 0 to 30 days after eclosion. The prey-deprived females, when provided with the cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae), laid fertile eggs, indicating that they had retained their reproductive potential. The oviposition period, post-oviposition period, fecundity, viability of eggs and longevity of females decreased significantly, whereas the pre-oviposition period and developmental period of progeny increased significantly with an increase in the duration of prey deprivation. There was no significant effect on the mean reproductive rate (16.14 ± 0.53 to 18.03 ± 0.67 eggs per day) at various prey deprivation levels, although the reproductive output and oviposition duration decreased. These findings indicate that lady beetle females can withstand the stress of prey non-availability, by switching to alternative food sources and reproducing when essential prey becomes available again.

The functional response of fourth instars, adult males and females of the sevenspotted lady beetle, Coccinella septempunctata Linnaeus (Coleoptera: Coccinellidae), was studied at different densities of aphid, Lipaphis erysimi (Kaltenbach) (Homoptera: Aphididae). The maximum prey consumption was recorded for fourth instars at the highest prey density (800) and the minimum for the male lady beetle at the lowest prey density (25). The prey consumption by the predatory stages of the lady beetle was directly and the percent prey consumption inversely proportional to prey density. Prey handling time decreased with increasing prey density. Regression analysis showed a linear relationship between the log number of prey exposed for predation and prey consumed. The predatory efficiency of the predator stages was directly proportional to prey density, indicating a Holling Type II functional response.

Fungus growing termites, Microtermes sp. and Odontotermes sp. are important pests of maize in southern Africa. They damage roots and stems of maize plants and cause lodging of plants after senescence. Termite nests are difficult to locate and destroy and no effective method of control has yet been developed. Different tillage methods that could destroy nests were evaluated in the field over two seasons. Tillage methods included deep chisel plough, shallow chisel plough, deep mouldboard plough, rip and rip-on-row. Significant differences were observed in the effect of different tillage methods on lodging of maize plants. The deep mouldboard plough treatment that disturbed and overturned soil to a depth of 0.30 m resulted in significant reduction in incidence of lodged plants. The deep chisel treatment disturbed the upper 0.25 m soil layer and also resulted in a significant reduction in the incidence of lodging. The shallow chisel and rip-on-row treatments had the highest incidence of lodging. Deep tillage methods are, however, not considered to be a long-term solution for termite damage in maize.