An experiment to examine the effects of different plant spacings on cowpea insect numbers and yields was undertaken at two sites in Nigeria. Two varieties, viz. Tvx 3236 and IT84E-1-108 were planted under field conditions at three different plant spacings. Plant spacing did not affect the number of Ootheca beetles, pod-borers, flower thrips and pod sucking bugs. Yield differences were not significant for the spacing regimes and there were no interactions between spacings and insect numbers for yields. Thus, plant spacing may not be an important control tactic in the management of the key cowpea insect pests in Nigeria.

Antixenosis resistance to Helicoverpa armigera (Lepidoptera: Noctuidae) was studied in 10 tomato accessions selected from a germplasm of 321 at Tamil Nadu, India, using free-choice and no-choice laboratory experiments. The foliage and fruits of two accessions, namely PT 4287 and Varushanadu Local were the least preferred for feeding in both tests. In the no-choice (confinement) test, Seijima Jeisei, Varushanadu Local and PT 4287 were the most preferred for oviposition, but had low egg hatch rates. In the free-choice test, these accessions were the least preferred for oviposition. The first and second instars preferred to feed on the foliage of 30- and 45-day-old plants, respectively than 60- and 75-day-old plants, whereas ovipositional preference was insignificant among the various plant ages.

The effect of growing cowpeas mixed with either beans or maize on population densities of Megalurothrips sjostedti (Trybom) was investigated. Also investigated was the effect of varying the cropping densities of the host plants on the pest populations.

There was a significantly lower population of M. sjostedti in cowpea/maize, bean/maize, and cowpea/bean/maize mixed stands as compared with that in either cowpea/bean stands or monoculture stands of cowpeas and beans. Increasing the cropping densities of the host crops increased the abundance of the pest in non-maize based mixed stands, but this effect was not observed in the maize-based mixed stands.

The results indicate that with regard to infestation by M. sjostedti, the practice of mixed cropping beans with cowpeas confers no advantage to either crop with respect to attack by M. sjostedti. On the contrary, combining the two crops attracted infestation levels similar to those attracted by either crop grown in monoculture. But the inclusion of a non-host plant (maize) in the mixture, significantly reduces infestation.

Field trials of various neem formulations were conducted to determine their effectiveness for the control of some major pests of eggplant, Solanum melogena (L), okra, Hibiscus esculentus (L) and cowpea, Vigna unguiculata (L), Walp. Various concentrations of neem emulsion reduced incidence of Selepa docilis (Butler), Urentius sp. and Zonocerus variegatus (L), on eggplant. Damage caused by Sylepta derogata (F), defoliator of okra, was less in plots treated with 5, 10 and 20% aqueous-methanol extracts of defatted neem cake. Moreover, neem seed cake applied as dust enhanced cowpea yield.

Investigations were carried out on the origin of osmeterial secretions exuded by fourth instar larvae of Papilio helenus and P. protenor that had been reported to secrete a variety of terpenic compounds. Variations in the chemical composition of the secretion induced by dietary and/or genetic factors were quantitative rather than qualitative in both species. Overall pattern of the chemical constituents was found to be highly species-specific and substantially invariable in a given species. Several sesquiterpene hydrocarbons secreted by the larvae were not present in detectable amounts in the leaves of the host plant, Fagara ailantoides, suggesting that the sesquiterpenes were biosynthesized by these larvae. Deuterium was efficiently incorporated in vivo into sesquiterpene hydrocarbons in the secretion, (E)-β−farnesene, β−caryophyllene, germacrene-A and germacrene-B, by topical application of deuteriumlabelled acetic acid to everted osmeteria, while similar treatment with deuterium oxide resulted in much lower incorporation of deuterium. These results provide evidence for de nova biosynthesis of sesquiterpene hydrocarbons in young Papilio larvae.

Studies were carried out from 1990 to 1993 to identify termite species associated with cocoa and coffee in Ghana. Ten genera/species, belonging to the families Termitidae and Rhinotermitidae, were recorded from cocoa and coffee trees aged from 6 to 36 months. The commonest was Ancistrotermes sp., followed by Amitermes sp., Microtermes subhyalinus, Microtermes sp. and Nasutitermes sp. Others were Macrotermes bellicosus, Pseudacanthotermes sp., Cubitermes sp., Schedorhinotermes putorius and Coptotermes sp. All species except M. bellicosus, Pseudacanthotermes sp. and Cubitermes sp. caused damage to cocoa and/or coffee. The shade tree, Gliricidia sp. was attacked by Pseudacanthotermes sp. whereas Macrotermes bellicosus and Cubitermes sp. were harmless. The relative abundance of these termites is discussed.

This paper, which discusses the current status of conventional insecticides in the management of stored product insect pests in the tropics, shows that insect infestation in stored products is high in the tropics and may lead to 100% damage in severe cases. Conventional insecticides used in their management, such as permethrin, lindane, pirimiphos-methyl, phostoxin, methyl bromide and io-dofenphos, and their methods of application are also discussed.

Methods of storing grains and other grain products are inadequate and in most cases reduce the efficacy of insecticides thereby enhancing the multiplication of the insects. The problems associated with insecticide usage in disinfesting stored products are highlighted and suggestions are made for their solutions.

The biology of two African sweetpotato weevil species, Cylas puncticollis and C. brunneus (Fabricius) (Coleoptera: Apionidae), was studied in laboratory experiments carried out at 27 ± 1°C, 45 ± 5% RH, and a 12 h photophase. Cylas puncticollis females lived longer than C. brunneus (141 ± 10 and 92±12 days respectively), developed faster (egg to adult 20–28 days, and 32–41 days respectively) and had a lower oviposition rate (1.10 ± 0.04 and 1.53 ± 0.06 eggs per female per day respectively). The total egg production per female (average 101), sex ratio (1:1) and proportion of eggs surviving to adulthood (average 89%) were similar for both species. The intrinsic rate of increase was higher for C. puncticollis (0.553 per 10-day period compared to 0.521 for C. brunneus). Under field conditions C. brunneus will benefit from its higher oviposition rate during periods of favourable conditions for sweet potato weevils, like dry spells which expose tubers for egg laying. Cylas puncticollis will benefit from its longer longevity during less favourable conditions, as females can survive extended periods when no oviposition sites are available and then resume egg laying when conditions improve.

Biochemical analysis of lakefly (chironomid/chaoborid mixtures and Povilla adusta samples) were conducted to determine their nutrient value and their potential as source of high quality nutrients in animal feeds. The results showed lakefly as rich in protein (62–67 g/100 g), fat (10 g/100 g) and ash (4–6 g/100 g). Moisture was low as was crude fibre. Povilla were richer in crude protein (67.4 g/100 g) and calcium (152 mg/100 g). The chironomid chaoborid mixture was however extremely rich in phosphorus (1.2 × 103 mg/100 g) and potassium (1.2 × 103 mg/100 g). Other trace elements were present in significant quantities as were niacine, thiamine and riboflavin. It is therefore deemed feasible to produce high quality nutrient concentrates from lakefly material for use in animal feeds. Further work Is however essential to determine lakefly digestibility and palatability and to ascertain suitable lakewide harvest techniques for the lakefly.

Indian siris, Albizia lebbeck (L.) Benth., is a useful tree that is being widely planted for shade in the Ahwaz region of southwest Iran. The tree is, however, severely attacked by the citrus red mite Eutetranychus orientalis Klein. Seasonal population dynamics of the mite were investigated on A. lebbeck in Ahwaz during 2010–2011. Eutetranychus orientalis had two population peaks on A. lebbeck. The first and second activity periods were observed from 10 August to 28 October 2010 and 24 February to 20 June 2011, respectively. The highest density and activity of E. orientalis was observed during September to November and April to May. During these months, the average temperature and relative humidity were 20–35 °C and 21–40%, respectively. The spatial distribution of the mite was evaluated using the parameters of Taylor's power law, which revealed an aggregated spatial distribution of E. orientalis on A. lebbeck. The results of the study could be applied to develop an integrated pest management programme against the pest.

Several terpenoids and oils were screened for vapour toxicity and repellency against the termite, Odontotermes brunneus. In toxicity tests, knockdown time KT50 and KT90 values were derived at 5 mg/cm2. For repellency screening, a new experimental setup was designed and effective time ET50 and ET90 values were determined at 2 mg/cm2. Among the compounds screened, eucalyptus oil produced the fastest knockdown (KT50 24.8 min) while β-ionone was found to be the least effective (KT50 536.0 min). Terpeneol (anhydrous) afforded maximum persistence of 338.0 min, whereas the least persistence was obtained from linalool (78.9 min) which prevented 50% of the population from crossing over the treated barrier (ET50).

The leafminer, Liriomyza trifolii Burgess, a polyphagous agricultural pest, can attack crops at different stages of development; some are attacked at the beginning of the crop cycle and others at the end of the cycle. Experiments on the differential susceptibility of the bean Phaseolus vulgaris and the potato Solanum tuberosum plants were done to get some information about factors which influence host selection by the leafminer. The distribution and density of leaf trichomes, as well as the nutritional status of the host plants, were found to be important in host selection. High trichome density acts as a physical deterrent to Liriomyza flies, just as senescing primary bean leaves induce non-acceptability. When given a choice, flies prefer bean to potato leaf discs, though the latter possess less trichomes. Other factors (chemical attractants and some nutrient components) might therefore also be involved in the complex host selection behaviour of L. trifolii.

The Nocardiaceae family members are symbiont bacteria from triatomine insects. The aim of this study was to detect the presence of Nocardiaceae family bacteria in Rhodnius ecuadoriensis intestinal bacterial flora. Bacterial colonies were isolated from the intestinal content from all insects; they had pink or coral pink pigmentation corresponding to Gram-positive coccobacilli. These isolates' biochemical identification by catalase and urease tests and the assimilation of different carbon sources led to Rhodococcus rhodnii being identified. This result was confirmed by 16S ribosomal ribonucleic acid gene sequencing. Additional studies are required to establish the symbiont role of this bacterium in R. ecuadoriensis as it has in Rhodnius prolixus.

The importance of rice in West Africa and the problem posed by pests were highlighted. Stem-borers are regarded as major insect pests of rice and available information on yield losses attributable to insect pests in general and stem-borers in particular, was reviewed. Damage caused by stem-borers usually results in “dead hearts” and “white heads” though other effects including a synergistic interaction between stem-borers and rice blast have been recorded. Survey methods and sampling of rice stem-borers were discussed and brief descriptions on distribution, behaviour and biology of the major rice stem-borers namely, Chilo spp., Maliarpha separatella, Scirpophaga spp., Sesamia spp. and Diopsis spp. were given. Current control tactics under investigation in West Africa include chemical, cultural and biological methods.

The mosquito C. p. pipiens L. never colonize sewerage water covered with duck weed. The Lemna minor vegetations affected the identification of the oviposition site by the females. The amputation of sensilla made the mosquito incapable of choosing the oviposition site. The immature stages of the mosquito are susceptible to the water borne synomones of the duck weed; the first instar larvae are most susceptible and have high mortality.

This paper reviews the work which had been done in Nigeria from 1911 to 1981 on several aspects of the biology of Zonocerus variegatus (L.), a variegated grasshopper pest of many food crops. The account covers recent advances in the areas of breeding biology, locomotory and migratory activities, morphometrics, feeding habits, parasitisation, and strategies for effective control of the grasshopper in Nigeria.

Termites (Isoptera: Termidae), white grubs (Coleoptera: Scarabaeidae) and millipedes (Myriapoda: Odontopygidae) are the major groups of soil pests that are widespread and of economic importance in groundnut production in sub-Saharan Africa. Other Coleopteran pests such as wireworms (Elateridae) and false wireworms (Tenebrionidae) are found to be of occasional importance. Farmers' cultural practices such as improper application of organic manure, leaving crop residues in farms, delay in planting and harvesting, and abiotic factors such as rainfall and soil texture also influence soil pest occurrence and damage. Groundnut farmers in most parts of sub-Saharan Africa seldom apply effective control measures against soil pests. This paper reviews the major soil pests of groundnuts and their damage, and discusses adopted control practices and their applicability in integrated pest management (IPM) modules, with an emphasis on the use of resistant groundnut varieties, cultural practices, botanicals and minimal application of synthetic insecticides.

Two studies were undertaken to determine the species composition of the phlebotomine sandfly fauna in the Mokolo region, an endemic focus of cutaneous leishmaniasis in northern Cameroon. The preliminary survey conducted in July 1994 using sticky paper traps recorded 843 sandfly specimens, all belonging to the two genera of the Old World sandflies, Sergentomyia and Phlebotomits. The species included S. (Sergentomyia) schzvetzi, S. (Sergentomyia) antennata, S. (Parrotomyia) africana and P. (Phlebotomus) duboscqi: From January 1996 to December 1996, a total of 3241 sandflies were collected using sticky paper traps. In this sampling, six out of the total of eight species recorded were of the genus Sergentomyia. In addition to the species recorded in the preliminary study, S. (S.) bedfordi, S. (Grassomyia) squamipleuris, S. (Sintonius), clydei and P. (Anaphlebotomus) rodhaini were sampled in 1996. This is the first report of S. squamipleuris ir Cameroon. The implications of this study to the transmission of cutaneous leishmaniasis are discussed with particular reference to P. duboscqi, a known vector of the disease in the region.

The effects of egg clutch size on development and survivorship of the larger grain borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) on maize were measured in the laboratory using single grains of the white maize variety, TZSR-W, at 30 ± 2°C and 70 ± 5% RH. Varying numbers of P. truncatus eggs (1, 2, 4, 8, or 16) were introduced into a hole drilled into a single maize grain. Destructive sampling was used at regular intervals to obtain data on immature developmental parameters, the location of immatures within the grain and the weight and sex of any emerged adults. First instars fed mainly on the floury endosperm tissue whereas the second and third instars preferred the germ tissue. Mortality due to competition was highest in first instars. At high initial densities (> 4 per kernel), some P. truncatus larvae reduced competition by moving out of the grain. A maximum of 6 adults emerged from a single grain. The mean number of adults that emerged per grain for initial egg densities of 8 and 16 were 3.3 and 3.5, respectively. Prostephanus truncatus adult weight at emergence was not significantly influenced by initial egg density except in the case of clutch size 16. The sex ratio of emerged adults was also unaffected by competition, and was always 1:1. Complete developmental period within grains ranged between 28 and 32 days.

We evaluated an aqueous extract of Duranta repens L. in the laboratory against the tea red spider mite, Oligonychus coffeae Nietner, to determine its effect on adult mortality, viability of eggs, oviposition deterrence and repellent properties. We also evaluated the same extract in the field to determine its effect on mite populations. The direct spray method was used in the laboratory at concentrations of 2, 4, 6, 8 and 10 g/l. Mortality of O. coffeae was dependent on both concentration and time after application. Deposition of eggs by adult mites on treated leaf surfaces decreased and the viability of eggs was also reduced. Its bioefficacy was comparable to that of the commonly used commercial neem oil formulation (azadirachtin 0.03EC). In addition, different concentrations of the aqueous extract of D. repens also exhibited repellent properties against adult mites. In the field, the application of the aqueous extract of D. repens reduced the mite population and its bioefficacy was comparable to that of the synthetic pesticide Propargite 57 EC. No phytotoxic effect was observed when tea bushes were sprayed with different concentrations of D. repens. Tea samples were taint free. Treatment of plants with the extract did not affect the quality (appearance of liquor, flavour, taint and taste) of made tea. Availability and distribution of this plant in and around tea growing areas of Assam, along with its processing, and the possibility of including D. repens extracts in the current IPM programme are discussed.