The efficacy of neem kernel cake powder water extract (NKCP-WE) and Dipel 2x (Bacillus thuringiensis var. kurstaki) in controlling the diamondback moth (DBM), Plutella xylostella Linn. (Lepidoptera: Yponomeutidae), on cabbage was evaluated in screenhouse experiments. All concentrations of NKCP-WE tested were larvicidal and plants treated with 25 and 50 g/l NKCP-WE retained larvicidal activity for up to 2 weeks after application. The efficacy of 25 and 50 g/1 NKCP-WE and 0.5 g/1 Dipel 2x was compared by observing DBM development on the treated plants and yields of those plants. Dipel 2x-treated plants had less DBM larval infestation than the neem-treated plants but the latter treatment gave better yield. The implications of these observations are discussed.

In the Chitwan valley, Nepal, Chilo partellus preferred maize and sorghum over rice, teosinte, finger millet and sugar-cane. Infestation on young maize plants produced “dead hearts” and on older plants reduced growth and sometimes prevented cob formation. The yield reduction in some maize cultivars reached 60% and stem infestation levels reached 98%. Borers produced “dead hearts” in young and “whiteheads” in older rice plants.

The egg, larval and pupal periods from April through September lasted 4–5, 16–41 and 4–8 days, respectively. A complete generation took 28–48 days under summer field conditions and 192–233 days from October to May. Of the one egg, four larval and two pupal parasitoids, all hymenopterans, which were reared from C. partellus, the two most important were Trichogramma chilonis (70% egg parasitism) and Apanteles flavipes (30% larval parasitism).

Stripe (st+) is a dominant trait on chromosome 3R in region 33B on the cytological chromosome map of Anopheles albimanus. It is expressed as a white longitudinal stripe in fourth stage larvae and pupae, and marks a Y-autosome translocation stock T(Y; 3R)3. Pseudolinkage analysis of the available markers to the translocation breakpoint showed complete absence of recombinant progeny between T(Y;3R)3 and st+. The two loci most likely either overlap or are very closely linked. This translocation strain can be genetically sexed by selection of the stripe marker.

The geographical distribution and host range in Nigeria of the mango mealy bug, Rastrococcus invadens Williams (Hemiptera: Pseudococcidae), a serious exotic insect pest of mango and many other crops is reported. The spread of R. invadens in Nigeria is at present limited to Lagos, Ogun and Oyo States of the humid south-west contiguous with the Republic of Benin, where the incidence of the pest has previously been reported.

Infestation has not been observed in any of the 11 states of the north nor in the Federal Capital Territory all of which have lower rainfall and relative humidity. R. invadens is highly polyphagous on over 20 species of host plants in 12 different plant families ranging from fruit crops which constituted 42.85% of the crops attacked, to food crops (14.28%), and to shade trees and ornamentals (42.85%). Severity of attack which was based on the number and area of foliage, Inflorescence and fruits attacked by R. invadens alone or together with sooty mould was highest in mango, citrus, breadfruit, guava and ornamentals including oleander, frangipani and roses. Hosts with mild infestation include maize, pawpaw and croton. The frequency with which infested plants are being felled, burnt or sprayed with synthetic chemicals suggests the panic which R. invadens attack has caused to growers.

The reproductive activity and the offspring development of the bruchid Callosobruchus maculatus (Coleoptera: Bruchidae) were monitored in the seeds of seven cultivars of Cicer arietinum and three cultivars of Vigna unguiculata. The number of eggs laid by the C. maculatus was higher on the V. unguiculata cultivars than on those of C. arietinum. The survival rate during the embryonic development was higher than 90% regardless of the plant species and cultivars while the post-embryonic development rates did not differ significantly between the cultivars. However, the duration of the embryonic and post-embryonic development and the weight of the emerging females varied with seed species. V. unguiculata seeds allow a higher reproduction and a better development than C. arietinum. In this study, no cultivar had been found to be resistant. In Algeria, C. maculatus can develop in stored grains of both chickpea and cowpea, and it is a major stored grain insect pest.

Genetic variation of resistance and tolerance to stem-borer, Chilo partellus, was studied in three sorghum crosses. Parents, F1 and F2 progenies were evaluated for per cent foliar damage and stem tunnelling as a measure of resistance or susceptibility. The parental cultivars involved in the crosses represented a fairly distinct range of character expression for plant height, foliar damage, stem tunnelling, stem lodging and grain yield. Means, degrees of dominance in F1 and inbreeding depression in F2 suggested that susceptibility was dominant over resistance in crosses susceptible x resistant and susceptible × tolerant, while resistance was dominant over susceptibility in the cross tolerant × resistant. The variation patterns of foliar damage and stem tunnelling in parents, F1 and F2 progenies suggested that they are different and are independently inherited. Both resistance and tolerance mechanisms are operating in sorghum resistance to stem-borers and these mechanisms are independently inherited. Estimates of heritability (broad-sense), genetic coefficient of variation and expected genetic advance, indicated that the cross Serena (tolerant) x IS 2146 (resistant) provides maximum chances of selecting resistant and tolerant plants in the segregating populations. Recurrent selection (population breeding) is suggested to improve the level of stem-borer resistance and tolerance and yield in sorghum.

A systematic account of the lepidopterous cereal stemborers in Africa is presented. The identification and distribution of the economically important species is discussed. Systematic problems are pointed out.

A chromatographically enriched fraction designated Fraction B from dry fruits of the plant Melia volkensii (family Meliaceae) was evaluated with the objective of determining its toxic and growth inhibiting effects on the larvae and adults of Culex quinquefasciatus mosquitoes. The fraction was purified from a crude methanolic extract by cold precipitation and elution of the precipitate dissolved in a hexane-ethyl acetate solvent system through a silica gel column. Larval treatments involved rearing the larval stages in water containing the fraction at concentrations of between 5 and 200 ppm. The LC50 for this fraction was found to be 34.72 μg/ml in 48 h. Second instar larvae were found to be more susceptible to fraction B when compared to fourth instar larvae. All fourth instar larvae that survived the treatment moulted into larval-pupal intermediates that were short-lived. The extract was also found to be an oviposition deterrent at a concentration of 20 ppm and above. It is concluded that M. volkensii extract has potential in the control of Culex quinquefasciatus.

Newly deposited Glossina morsitans morsitans larvae were chilled over ice and inoculated with 1 μ1 of either virus suspension derived from Glossina pallidipes salivary gland homogenate or sterile tsetse physiological saline. They were allowed to pupariate and then maintained at 25°C, 70% r.h. until soon after emergence when their salivary glands were examined for enlargement and presence of virus particles. Teneral G. m. morsitans which received the virus inoculum (n = 135) as larvae all became infected as revealed by gross hypertrophy of their salivary glands and ultrastructural manifestation of virus particles within the glandular epithelial cells and lumina. In the control group, which received the tsetse physiological saline (n = 91), only 1.1% of the flies showed the salivary gland enlargement, a level equivalent to the prevalence of virus infection normally detectable in the G. morsitans colony. This technique opens the way for testing the biocontrol potential of this virus. The DNA virus from G. pallidipes is clearly infective to G. morsitans morsitans, suggesting that the hypertrophied, chalky-white salivary glands, reported in various Glossina spp., are a manifestation of infection by one and the same virus.

Glossina pallidipes, a widely but discontinuously distributed African savanna species, is one of the economically important tsetse flies because it is a vector of trypanosomiasis, a lethal disease of cattle and other domestic animals. DNA sequences of ribosomal (r16S2, 249 bp) and cytochrome oxidase I (COI, 421 bp) concatenated mitochondrial genes were analysed in 23 geographically diverse samples of G. pallidipes from Ethiopia, Kenya, Tanzania, Zambia and Zimbabwe. Among 873 flies, we detected 181 composite haplotypes and found that their spatial diversities and frequency distributions were heterogeneous. Haplotype and nucleotide diversities were greatest in Ethiopia and least in southern Africa. We observed little haplotype and nucleotide diversity among regions, and detected severely limited maternal gene flow among the sampled populations (ΦST= 0.42). Tests for demographic stability and analysis of mismatch distributions revealed regionally contrasting demographic histories. The Ethiopian populations were phylogenetically the oldest and genetically the most diverse, and exhibited successive waves of contraction and expansion. The southern African populations were phylogenetically the youngest and genetically the least diverse, and showed only a single, recent expansion. Likely ecological correlates of historical tsetse fly demography include population suppression trials in East Africa and recurring rinderpest epizootics in southern Africa, beginning in the late nineteenth century that reduced host mammalian populations.

Pesticide spray thresholds, as a component of Integrated Pest Management, must be integrated with the world of smallscale farmers if they are to be useful to them. The capacity and desire to spray have specific features of significance for threshold control. Threshold use may be encouraged by maximising the divisibility of pesticide technology. Farmers' perception of thresholds, often subjective and personal, may be enhanced by information learned from outsiders, as complementing, rather than supplanting, their existing knowledge and experience.

Phytosanitary measures are a major barrier to trade in papaya. We assessed the infestation of tephritid fruit flies on different stages of maturity of papaya, to determine its non-host stage of maturity, for market access. Papaya fruits were collected from Kilifi and Embu counties, Kenya from March 2013 to December 2014, to assess the level of infestation by fruit flies according to the degree of fruit ripening. In all locations, no fruit fly infestation was recorded on papaya when fruits were at the 0, 25 and 50% yellow fruit ripening stage. Bactrocera dorsalis (Hendel) was, however, observed attacking fruits when papaya fruits were at 75 and 100% all yellow (fully ripe fruit ripening stage) with infestations of 0.19−0.51 B. dorsalis/kg fruit and 0.24−1.24 B. dorsalis/kg fruit, respectively, in all locations. Field cage exposure of B. dorsalis to fruits of five papaya cultivars—‘Papino’, ‘Neo Essence’, ‘Sunrise Solo’, ‘Tainung No. 1’ and ‘Tainung No. 2’ in Manica Province, Mozambique—showed that B. dorsalis did not infest fruits at 0, 25 and 50% yellow ripening stages at the densities of 50 and 100 flies per cage. However, at 75% yellow ripening stage, up to 13.1 pupae/kg of fruits was recorded at a density of 150 flies per cage in Tainung No. 1, and infestation ranged from 4.5 to 136 pupae/kg fruits at 100% yellow ripening stage across all the cultivars and infestation densities. Laboratory evaluation of volatiles emanating from freshly crushed papaya pulp of four cultivars: ‘Sunrise Solo’, ‘Red Lady’, ‘Papayi’ and ‘Apoyo’ on egg viability of B. dorsalis showed that at 0, 25 and 50% yellow, egg hatchability was inhibited, suggesting that semiochemical compounds present in green tissues of papaya prevent egg development, although this effect was variable across the four cultivars and ripening stages. Export papaya is harvested at less than 40% yellow ripening stage. Our results, therefore, suggest that quarantine treatment for fruits at this ripening stage is inconsequential, as B. dorsalis does not infest papaya fruits at this stage; thus, authorities should permit entry of these papaya cultivars of less than 40% yellow ripening stage to quarantine-sensitive markets.

The oviposition behaviour of the cowpea weevils, Callosobruchus rhodesianus (Pic.) and Callosobruchus maculatus (F.) on clean and egg-laden adzuki beans was examined in choice and no-choice experiments. The oviposition rate of C. maculatus was greater than C. rhodesianus in both experiments. Both weevil species were able to distinguish between clean and egg-laden beans. Discrimination by both species was greater against seeds with 12 eggs than with 6, regardless of which species had previously laid eggs. There was a weak indication that the presence of C. maculatus eggs at high densities might reduce the oviposition rate of C. rhodesianus.

A random sample of 90 small scale cotton growers was selected and interviewed in three target areas, to investigate the perceptions of farmers towards cotton insect pest management in Zambia. Information is given on farmers control practices, their perceptions of insect damage and the effectiveness of control. All farmers interviewed were knowledgeable about the common insect pests of cotton. The American bollworm (Heliothis armigera), red bollworm (Diparopsis castanea), and aphids (Aphis gossypii) were reported to be the worst pests. Some farmers use more insecticide applications than is locally recommended probably because they overestimate potential losses. Many farmers felt that the insecticides they use (pyrethroids) are very effective against pests. In some cases, the ED formulation of cypermethrin was reported to be more effective than EC formulations. The commonly practised nonchemical methods of insect control are growing cotton in rotation with other crops and destruction of cotton plants after harvest. Only a few farmers were aware of the role of biological control and the significance of weeding in cotton pest management. Many farmers inspected their crops to decide the timing of spray applications but did not follow the recommended scouting methods.

A survey among 240 resource-poor farmers at the Kenya coast indicated that insect pests were considered to be the main production constraint. Over 70% of respondents mentioned stemborers to be the most important insect pest. Unlike the eggs and adults, stemborer larvae and pupae were frequently seen by farmers. Alternative gramineous host plants for pests were common near maize fields and were often not destroyed until after the first rains. Nearly all farmers left dry stems and stubble in the field after harvest. Farmers knew of many methods for controlling stemborers, but only 32 and 56% of farmers in Kilifi and Kwale Districts, respectively, used any of the methods. Chemical control was the most popular control method, being applied regularly by 19 and 38% of farmers in Kilifi and Kwale Districts, respectively. Traditional methods and cultural control methods were seldom used. Approximately 50% of farmers had heard of beneficial insects, with farmers collectively mentioning 17 predators of stemborers. Cocoons of the parasitoids Cotesia flavipes, released in a biological control programme in the study area in 1993, and the indigenous Cotesia sesamiae had been seen by 33% of respondents, but none knew what these were. The results of the present study stress the need to educate farmers about the biology and ecology of stemborers and the role of natural enemies. Also, after effective control methods suitable for resource-poor farmers have been identified, both groups should be trained in pest management methods, for example through the Farmers Field School approach.

Coelomomyces indicus was reisolated from six larvae of Anopheles gambiae in Uganda. A crustacean copepod Cyclops sp. was found to be infected (63%). This indicated that the copepod could be an intermediate host for the fungus. All the four instars were highly susceptible to C. indicus but fourth instar Aedes aegypti was fairly susceptible (94.2%), while second instar An. gambiae (100%) and second instar C. fatigans (100%) were the most susceptible.

Laboratory tests were conducted to compare reproductive capacity and longevity of An. gambiae, C. fatigans and Ae. aegypti when infections of C. indicus were induced in each of the different larval instars. Infections of C. indicus sharply reduced the reproductive capacity and longevity of An. gambiae, C. fatigans and Ae. aegypti, regardless of the instar that were exposed and became infected. The reductions were highest when first and second instars were exposed. The tests indicated that introduction of C. indicus into laboratory populations of An. gambiae, C. fatigans and Ae. aegypti consisting of mixed larval instars, could significantly reduce the number and fertility of eggs and thus result in an average reduction of about 65.4% for An. gambiae, about 46.7% for C. fatigans and 58.7% for Ae. aegypti of the F1 progeny from those females that became infected. The importance of these results in biological control is discussed.

The life history of Amblyseius fustis (Pritchard and Baker) was studied in the laboratory at a fluctuating temperature and relative humidity ranging from 24.4 to 28.0°C and 55.5 to 75.6%, respectively. The developmental stages consist of egg, larva, protonymph, deutonymph and adult. The life cycle, from egg to adult of both male and female was about 8 days, while longevity was about 19.2 days. Mated female laid an average of 18.8 eggs. There was no significant difference in the longevity and fecundity of predators fed on different life stages of the host. The proportion of male to female in the progeny of mated females was 1:4.

A. fustis has a shorter developmental period and lives longer than its prey, but the latter is more fecund (26.9 eggs/♀) and has a higher proportion of females in its progeny (1:4.8). The shorter developmental period and the longer life span of the predator are likely to offset the higher fecundity of the prey.

Establishment and maintenance of a laboratory colony of Phlebotomus argentines are described which presently is in the nineteenth generation. Larvae were reared in modified plastic vials and were fed with a newly prepared food. Emerged flies were kept in adult holding cages at 50–90% r.h. and 25–26°C and provided with 30% sucrose solution. The average development time (egg to adult) of each generation in the laboratory was about 32 days at 28–31°C. Adult females were fed blood on hamsters, humans and white mice. Observations were made on mating behaviour, host preference, oviposition, effect of temperature, etc.

Two mark-release-recapture experiments were carried out on a female population of A. africanus in the Zika Forest, in Uganda, to estimate density, survival rates, dispersal range and duration of the gonotrophic cycle. Marking was achieved using powdered fluorescent pigments and wet paint. In the first experiment, unfed A. africanus female mosquitoes were marked and released. A high overall recapture rate of 17.6% was recorded consisting mainly of first recaptures (up to 85.6%). The highest recapture rate was recorded during the first 4 days after release. Using Jolly's Stochastic Model, daily population estimates ranged from 1386 to 8406 during the first 7 days of release. The daily average population estimated over the first 10 days was 3591. Using the Simple Lincoln Index, population estimates ranged from 1104 mosquitoes to 16,320 with an average daily estimate of 3706. Of interest was the fact that the average daily population estimates using the two methods were not statistically significant. The 24-hr survival rate averaged over 9 days was 0.9228. Dispersal was rather random, and appeared to be of a limited range with an average distance of 50 m. In the second experiment, which involved marking only fully engorged mosquitoes, an overall recapture rate of 7.1% was recorded, with an average daily survival rate of 0.8209 averaged over the first 4 days. The pattern of recaptures indicated a gonotrophic cycle of 5–6 days with a small proportion of mosquitoes seeking secondary feeds during the first 48 hr. It was generally observed that marking and handling did not have any marked effect on mosquitoes during the first 8 days.

There were significant differences in the level of susceptibility among the 12 varieties which were screened for resistance to A. lycopersici Pronounced tolerance to leaf damage was recorded on varieties Early Stone Improved and Beauty. Oxheart and Bonny Best both of which had comparatively lower mite densities were highly susceptible. Flower bud formation was not significantly affected by the mite damage. However, the number of dead flowers and flower buds on infested plants was significantly more than on protected ones.

Russetting of young fruits due to mite damage differed significantly among the varieties tested, and was positively correlated with moisture content of young fruits. The least and most affected varieties were Beauty and Red Cloud respectively. The percentage yield loss was highest on Hybrid Beefmaster and Oxheart and lowest on Roma and Money Maker.