Computer programming is ideal for the identification of ticks. This is due to the ability of computers to make rapid, repeated and complete searches of a large database of features in answer to a series of questions which lead to a single species. The program can allow the search to start in any order and to avoid difficult questions. It enables illustrations to be displayed when a question is asked. In contrast, classical dichotomous keys need to be used in a fixed sequence in which it is difficult to avoid questions, and often use vaguely defined characters and obscure language. To program an electronic key a character state matrix is constructed of rows of precisely defined characters with the two or more states in which they may occur and of columns in which the species are placed. Each state is recorded as being positive or negative. This corresponds to the binary system needed for computing and this need enforces a discipline on the identification method that has to define in illustrations and precise standardized language the characters and their states. These concepts are illustrated by the development of ‘Multikey’ program for the identification of ticks of domestic animals in Africa. The advantages of Multikey are its ease of use, its compatibility with comprehensive tick guides on compact discs and the ability to expand it with more information. The disadvantages are the requirement for a computer next to the laboratory microscope and the difficulty in browsing the contents. These disadvantages can be overcome by a printed version and there is use for both the printed and the electronic versions of such guides.

Lentil seeds infested with Callosobruchus chinensis (Linnaeus) for 12–15 days were exposed to Dinarmus basalis (Rondani) alone, Anisopteromalus calandrae (Howard) alone, or to both species, at densities of 2, 4, 8, 16 and 32 insects. Intra-specific competition and host emergence decreased with increasing parasitoid density in both D. basalis and A. calandrae, but progeny production of the parasitoids and parasitoid-induced mortality (PIM) increased with increasing parasitoid density. Dinarmus basalis was much more efficient in parasitizing C. chinensis than A. calandrae. Emergence of D. basalis and A. calandrae, and the PIM were highest at a parasitoid density of 32. Parasitoid density and a combination of parasitoids significantly (P<0.01) affected the number and progeny sex ratio of emerged parasitoids. There were significant (P<0.01) effects of inter- and intra-specific competition on host mortality. Host mortality increased with increasing parasitoid density. Parasitoid combination and parasitoid density also significantly affected PIM.

In order to predict host accessibility by the pupal parasitoid Xanthopimpla stemmator (Thunberg), four grass species (Sorghum bicolor, Pennisetum purpureum, Sorghum arundinaceum and Zea mays) were sampled for stemborer pupae in Kwale, in the low altitudes of southern Kenya, and in Trans-Nzoia, in the high altitudes of western Kenya. The pupal position of Chilo orichalcociliellus (Strand), Chilo partellus (Swinhoe), Sesamia calamistis Hampson, Sesamia sp. nr oriaula (Tams and Bowden) and Busseola fusca (Fuller) in the plant were determined in relation to (a) the distance of pupae from the edge of the stem (depth), (b) the distance between the moth-exit hole and the head of the pupa (location) and (c) the length of the tunnel from the moth-exit hole to the base of the tunnel. Pupal depth and location for C. partellus and B. fusca varied significantly in the different plant species tested, and the pupae tended to be embedded deeper in cultivated than wild hosts. On all host species, the borers were located at a depth less than 0.35 cm. Most C. orichalcociliellus and S. calamistis pupae were found pupating in the ears of maize or the upper part of the wild hosts' stem. Sesamia sp. nr oriaula was only collected from the lower parts of P. purpureum. For B. fusca, tunnel length varied significantly among plant species and was longer in cultivated hosts. Xanthopimpla stemmator has an ovipositor length of about 0.52 cm, thus it is anticipated that the parasitoid could easily reach and parasitize the pupae in these host species.

The effect of covering post-harvest banana stumps with soil on banana weevil Cosmopolites sordidus (Germar) oviposition levels was investigated at three locations, Sendusu, Kawanda Agricultural Research Institute (KARI) and Ntungamo district of southwestern Uganda. In the first experiment oviposition levels were assessed in a banana system comprising growing plants and residues. Oviposition increased on sword suckers, reaching a peak 1–7 days after harvest and decreased thereafter. In the second experiment conducted on farmers' fields, corms received 70% of the eggs and pseudostems 30%. The area 5–10 cm below the collar received 27% of the eggs, the area 0–5 cm above the collar 30% and the area 5–10 cm above the collar 0.3%. The remaining eggs (43%) were laid 0–5 cm below the collar. The effect of stump height and covering the stumps was evaluated in both the wet and the dry seasons at Kawanda and Ntungamo. Cutting stumps to the ground level alone had no effect on oviposition. Covering post-harvest banana stumps reduced C. sordidus oviposition in the wet but not in the dry season.

The pod-sucking bug Clavigralla tomentosicollis Sta˚l is the most important insect pest associated with cowpea in Africa and Burkina Faso, which causes seed malformation and destruction. The nutritional quality and physical structure, which vary according to the development stage of the pods, could have an impact on the biology of the bug. This laboratory study carried out at Kamboinse´ research station in Burkina Faso aimed at evaluating the effect of rearing the bug on three different types (young pods without grains, pods in filling stage and mature pods) of cowpea var. KVx 396-4-5-2-D, on the biology of C. tomentosicollis. The bug larvae were also fed on pod shells alone and on grains alone to identify which part and which stage of the pod would be most appropriate for bug growth and development. A qualitative chemical analysis of the shells and the grains was conducted to determine the compounds that might have an impact on insect growth in relation to the pod development stage. The best performances of larva and adult growth were recorded when the larvae were fed on pods in the filling stage. Most larvae fed on young pods extended their development period and died before completing the development cycle. Mature pods were less suitable for larval growth. Chemical analysis revealed that, compared to pods in filling stage, both the shells and the grains of mature pods contained antitrypsin and cyanogenetic heterosids (only in grains), hence their toxicity against the insect. It is recommended that control measures should target the filling stage, which is most susceptible to the bug damage.

The influence of two photoperiods (14L:10D and 24L:0D) and four wavelengths of light [white (control), blue (c. 475 ran), yellow (c. 570 nm) and red (c. 650nm)] on development and reproduction of the ladybird, Propylea dissecta (Mulsant), was investigated. The photoperiod of 14L:10D and the white-light wavelength recorded fastest development, maximum survival and reproduction. The developmental and reproductive Performance decreased in the order white > yellow > blue > red. The effect of the wavelength is probably due to the differential predatory response under different coloured arenas.

A network of experiments was established in three different agroecological areas at the periphery of the Central Plain of Thailand during three successive years to assess the effect of a multiple insect pest complex on cotton yield loss. A large range of combinations of jassid and bollworm injuries was achieved from the application of several insecticide treatments and sowing dates. Other pests were of minor incidence. Seed-cotton yield varied from 0 to 3600 kg/ha, and yield losses due to pests ranged between 0 and 100% of the attainable yield. Damage mechanisms were addressed through path coefficient analysis of the interaction between injuries and plant compensation. Before boll production, jassids were the most serious pests, while bollworms had a positive effect on vegetative growth. At the fructification stage, bollworms were very harmful, while sucking insects such as jassids became progressively less important. Injuries did not necessarily lead to yield losses because of the plant compensation ability. Cotton response to pest injuries depended on the development stage and crop status. Decisions made on cotton protection against pests should thus consider the development stage of the crop and interactions between injuries instead of the traditional single pest population threshold. This study of a plant–pest system exemplifies the need to incorporate plant compensation processes in the design of pest management programmes aiming at reducing insecticide use.

Host searching, slit making, egg deposition and protection are distinct sequences of one event, which lead to oviposition on the lower surface of rice leaves by the rice hispa Dicladispa armigera (Olivier). Females spent an average of 8.05±1.35 min in selecting an oviposition site, 6.40±0.25 min in preparing a triangular slit, and 1.17±0.07 min in laying and protecting a single egg. An egg measuring 0.85×0.42 mm in size was partially inserted inside a slit of 1.95×0.84 mm. The female exhibited ovipositional preference among the leaves of a rice plant, as 67.5% of eggs were deposited in the first leaf. On the first, second and third leaf, the female deposited her eggs mostly in the middle part of the leaf blade, avoiding the area between 4.15–4.89 cm from the tip and 12.72–14.25 cm from the base of the leaf.

An artificial diet for mass rearing of the tobacco caterpillar Spodoptera litura (Fabricius) from the neonate to adult stage was developed at 27±1°C, 65±5% RH and 16:8 h scoto/photo-phase regime. The diet ingredients consisted of wheat germ (26.0 g), kidney bean flour (51.3 g), chickpea flour (56.0 g), yeast powder (31.6 g), casein (15.2 g), l-ascorbic acid (3.2 g), cholesterol (0.5 g), two multivitamin multimineral capsules, one vitamin E capsule, ABDEC drops (2 ml), castor oil (1 ml), methyl-p-hydroxybenzoate (1.8 g), sorbic acid (1.3 g), streptomycin sulphate (0.25 g), formaldehyde solution (2 ml), agar–agar (16.4 g) and 820 ml distilled water. The new artificial diet successfully supported the growth and development for more than ten generations with enhanced reproductive potential. The mean biological parameters based on rearing of ten continuous generations showed higher pupation (89.2%), emergence (97.2%), survival (86.6%) and fecundity (2486.2 eggs) as compared to the most preferred natural food, castor leaf whose respective recorded values are 80, 75, 60% and 480 eggs. The cost of 1 l of the diet was approximately US$ 2.00 only, on which 200 neonate larvae can be reared. The artificial diet developed is suitable for mass rearing S. litura successfully throughout the year for laboratory and field experimentation as well as for commercial production of nuclear polyhedrosis viruses (Sl NPV).

This note reports an unusual case of a high number of oocysts found by dissecting the midgut of Anopheles dirus Peyton & Harrison from Laos, where dissections have not been carried out for many decades. In dissected samples, the number of oocysts ranged from 1 to 250 and tests carried out on the heads and thoraces of A. dirus using the ELISA method were positive for Plasmodium falciparum.