The aim of this study was to document what water types were most stimulatory to oviposition by the malaria mosquito, Anopheles gambiae Giles s.s. In laboratory choice tests, dishes of black cotton and red laterite soils from around Kisumu, Kenya, equally stimulated An. gambiae oviposition when saturated with water. When infused into either soil type, water from Lake Victoria was significantly more stimulatory than any other type of water or infusion tested. Water from natural An. gambiae puddle habitats, borehole water, cow dung infusion, Bermuda grass infusion and distilled water followed in declining rank order. Relative to An. gambiae puddle-habitat water and distilled water, Lake Victoria water appears to provide the strongest chemical cues for An. gambiae oviposition recorded to date. This work suggests that this important vector of human malaria may oviposit in and around Lake Victoria, as well as in its usual puddle habitats. Lake Victoria should be explored for its possible contribution to malaria mosquito populations.

The performance of the Bombyx mori Linnaeusbivoltine hybrid, Shaanshi BV-333, was evaluated on six mulberry cultivars ofMorus spp. based on economic charactersin rearing and mulberry leaf quality. The growth rate and morphologicalcharacteristics for all the cultivars were studied using several parameters.Specific characters such as disease resistance, survival percentage, cocoonweight, cocoon shell weight and single cocoon filament length were recordedduring the rearing of silkworm larvae. Tested cultivars significantly differedin all parameters. Cultivars Kanva-2/M5, Thailand, Thika and S-36 exhibitedsuperiority in rearing performance over other tested cultivars. Silkworms fedwith cv. Thailand had the highest survival percentage of larvae in the short(S1) and long (S2) rainy seasons as compared with other cultivars. However, cv.Embu produced the lowest mortality during the dry season (S3), while S-41produced the lowest survival rate in all seasons. Embu had significantly higherfilament length and cocoon yield compared with the other cultivars during S3.However, S-41 performed poorly in survival percentage, cocoon yield, silkreeling and cocoon shell weight.

The effect of visual and olfactory stimuli from leaves of two maize cultivars, Basilocal (susceptible) and Kisan (resistant), in eliciting orientational responses by first instar Chilo partellus (Swinhoe) larvae was investigated in the laboratory. The polar and non-polar chemical constituents of these cultivars were extracted in methanol and hexane, respectively. Orientational preference of the larvae for the leaf whorls and hexane extracts of Basilocal leaves was significantly greater than that for Kisan. The methanol extracts of the two cultivars were, however, equally effective in eliciting larval attraction. These observations imply that the non-polar fraction of maize leaves is more effective than the polar fraction in eliciting larval orientation in C. partellus. Moreover, certain chemicals of Kisan leaves, extractable in hexane, elicited larval repulsion whereas those of Basilocal leaves elicited larval attraction. Identification of the chemicals eliciting attraction or repulsion would be valuable in a management programme for this economically important insect pest of gramineous crops.

Sitophilus zeamais Motschulsky is an important field-to-store pest of maize in several parts of Africa including Cameroon. Although synthetic insecticides are effective at controlling the pest, the environmental and health hazards of these chemicals are of increasing concern. This study assesses the efficacy of ashes of local plant material against S. zeamais in the western highlands of Cameroon as an alternative to synthetic insecticides. Laboratory studies on toxicity against F1 progeny of S. zeamais were conducted using leaf ashes of Cupressus arizonica, Eucalyptus grandis, Ocimum gratissimum and root ash of Vetiveria zizanioides at the rates of 0.1, 0.25, 0.5 and 1.0 g/25 g maize grains in Kilner jars. Toxicity of E. grandis ash extract was also evaluated. The ashes of E. grandis and O. gratissimum at the rate of 0.25 g/25 g grains significantly reduced the number of emerged weevils. Eucalyptus grandis ash showed toxicity (1.0 F1 progeny emerging at 0.25 g/25 g grains compared with 16.5 for the control). Eucalyptus grandis ash at 20 g/2 kg grains significantly reduced grain weight loss and protected grains for 6 months without adversely affecting the germination of the seeds. Ethanolic E. grandis ash extracts at rates of 50,000 and 100,000 ppm significantly (P < 0.05) reduced the number of emerged F1 progeny of S. zeamais.

Many pests, especially capsid bugs, infest cocoa and contribute to low yields in producing countries. In Ghana, synthetic pesticides are recommended for controlling the insect pests, and a combination of synthetic pesticides and cultural practices for diseases and weeds. However, the farmers in Ghana are not motivated to adopt these recommendations due to the high cost of pesticides and low producer prices. There is also concern that use of synthetic pesticides on a wide scale can affect both human health and the environment. With the objective of improving cocoa yields through environmentally friendly pest control practices, evaluation of an integrated pest management (IPM) package based on aqueous neem (Azadirachta indica A. Juss.) seed extracts to control the insect pests and cultural practices to manage the diseases, weeds and parasitic plants was undertaken in farmers' fields with their active participation. The IPM package improved yields significantly and was found to be more profitable than the farmers' practices. However, there are two major constraints to adoption of the package by farmers: it is labour-intensive and currently, neem is not readily available to the community. The study recommends that these constraints must be tackled to motivate the farmers to adopt or adapt the IPM package.

The salivary glands of the cowpea pod-sucking bugs Anoplocnemis curvipes (Fabricius), Clavigralla tomentosicollis Stål, Clavigralla shadabi Dolling, Riptortus dentipes (Fabricius) and Mirperus jaculus (Thunberg) are described and illustrated. Extracts of the glands were assayed for the presence of proteinases, α-amylase, β-amylase and amyloglucosidase. The salivary glands consist of four-lobed principal glands and a tubular accessory gland, and they differ in shape and size among the different species except for the median lobe, which is more or less spherical. The sickle-shaped nature of the posterior lobe reported before for Riptortus linearis (Linnaeus) was also observed in R. dentipes, suggestive of a probable generic characteristic. Anoplocnemis curvipes has the biggest salivary gland, and it is followed by R. dentipes, M. jaculus, C. tomentosicollis and C. shadabi in descending order. Assays of the gland extracts revealed that the four digestive enzymes tested are present in the five coreoid species. Proteinases were preponderant (1.4–94.9 μg/ml), while amylases were detected in traces [(0.5–11.0) × 10− 3 μg/ml]. Proteinases may be largely responsible for the feeding damage caused by the coreoid species and their concentration in the glands of the different species correlates well with their known capacity to inflict pod damage and yield reduction in cowpea. Fourth instar nymphs of the different species also had higher concentrations of the digestive enzymes compared with their respective adults; and this correlates with the known ability of the nymphs to cause greater pod damage and yield reduction than adults.

In situ field level mass production of Amsacta albistriga nucleopolyhedrovirus (AmalNPV) was achieved at Pavagada (Karnataka, India) during September 2004. The yield of virus mass produced in situ in the field was 5.05 times greater than that when produced in the laboratory. This technique is farmer-friendly, easy to execute and much cheaper than laboratory production, having the potential to be used for the mass production of NPV of gregarious pests that occur in large numbers.