Five mutants for seed coat colour from the faba bean, Viciafaba L. variety BF 2/2 (Beladi) were tested qualitatively and quantitatively for tannin content. The susceptibility of the mutants to Bruchidius incarnatus (Boh.) and Callosobruchus maculatus (F.) was also evaluated. All seed coats contained tannins (0.75–3.75%). The darker the colour the lower the tannin content. Cotyledons with testas removed were devoid of tannins. The thickness of the seed coats ranged from 0.146–0.155 mm, however, differences among mutants were not significant. Faba seeds were more suitable for the multiplication of B. incarnatus than C. maculatus. The poor performance of the latter was manifested as low fecundity, high mortality and longer developmental period. It was concluded that selection for white coloured faba seeds should not be discouraged on the basis of its assumed susceptibility to bruchids.

Investigations were conducted to establish field responses of Glossina pallidipes, G. m. morsitans, muscoids and tabanids to castor, raw linseed, paraffin and chlorinated paraffin oils in deltamethrin suspension concentrate (sc) formulation, through randomised Latin square experiments. Tsetse landing responses on targets treated with 400 ml/m2 of any of the oils in 2 g/m2 deltamethrin formulation were significantly lower than on non-oil-containing deltamethrin formulations, for both G. pallidipes (F(4,32) = 4.855, P = 0.00357) and G. m. morsitans (F(4,32)=2.421, P = 0.06862).

The landing response indices, relative to the control formulation without oil, were 0.60, 0.70, 0.61 and 0.41 in G. pallidipes and 0.92, 0.82, 0.75 and 0.42 in G. m. morsitans and for paraffin, chlorinated paraffin, castor and raw linseed oils respectively. Glossina pallidipes and G. m. morsitans landing responses were inversely proportional to raw linseed oil concentrations. None of the oils significantly affected muscoid (F(4/32) = 1.6959, P = 0.1753) or tabanid (F(4,32) = 1.7546, P = 0.1624) landing response, or tsetse fly resting persistence (F(4,32) = 0.9641, P = 0.4406) on the targets.

The reduced tsetse fly response to targets treated with any of the oils can be attributed to adverse effect of the oil treatments on the tsetse fly olfactory responses to the targets. Since the oil formulations reduce target efficiency by reducing tsetse responses to the targets, application of the oil formulations on targets deployed in G. pallidipes and G. m. morsitans control programmes is not recommended.

The insecticide activity of synthetic pyrethroids to Triatoma infestans was tested by topical application. Deltamethrin, fenpropathrin, bioresmethrin, permethrin, cypermethrin, d-phenothrin and cyphenothrin showed the highest activity.

The susceptibility to poisoning of adult insects by these pyrethroids (except bioresmethrin) was increased by cotreatment with profenofos or with piperonyl butoxide (PBO). Assayed pyrethroids synergized by PBO showed similar general structure.

The vinyl cyano pyrethroids showed a knockdown effect with a delayed recovery. During 15 days after intoxication with deltamethrin, insect recovery was observed. Recovery blockage by PBO was observed in cyphenothrin and deltamethrin poisoning at low doses.

Coptotermes heimi (Wasmann) is a termite widely present throughout Pakistan and causes detrimental effects in standing trees. In this study, the feeding preferences of C. heimi for 18 different wood species were determined through choice and no-choice trials under laboratory and field conditions. In no-choice laboratory trials, different combinations of wood blocks were used to determine wood consumption by C. heimi. Weight loss, consumption/individual and survival rate were evaluated. Populus euramericana was found to be the most susceptible wood species and Syzygium cumini the most resistant one. Nine different wood combinations were used under choice laboratory conditions; maximum feeding was recorded in P. euramericana and Pinus roxburghii (50.8–24.5 mg). However, minimum feeding was recorded in S. cumini (2 mg) and Tectona grandis (14.9 mg). Under no-choice field conditions, minimum feeding was recorded in S. cumini (9.5 mg) and maximum feeding in P. euramericana (60.5 mg). Under choice field conditions, maximum (58 mg) feeding was recorded in P. euramericana and minimum feeding in S. cumini. Feeding preferences in descending order based on wood consumption as a quantitative parameter documented were as follows: P. euramericana>Ailanthus excelsa>Azadirachta indica>P. roxburghii>Butea monosperma>Morus alba>Bauhinia variegata>Albizia lebbeck>Dalbergia sissoo>Heterophragma adenophyllum>Erythrina suberosa>Cassia fistula>T. grandis>Mangifera indica>Eucalyptus camaldulensis>Jacaranda mimosifolia>Bambusa bamboo>S. cumini.

The African rice gall midge (AfRGM) Orseolia oryzivora Harris and Gagné is an important insect pest of rice in Nigeria. Studies were conducted at Ogidiga (forest zone) and Edozhigi (southern Guinea savanna) in Nigeria, under rainfed lowland conditions during the 2006 and 2007 rainy seasons, on the population dynamics of AfRGM adults using light trap and random sampling of % tiller infestation (plant damage due to AfRGM) and % parasitism by Platygaster diplosisae Risbec and Aprostocetus procerae Risbec (parasitized larvae and pupae and parasitoid species present in dissected tillers). The results obtained showed that AfRGM populations were relatively low in June and July – the beginning of the 2006 and 2007 rainy seasons, respectively – and increased abruptly from September, reaching a peak in October at both locations. The increase was attributed to the rapid build-up of the pest populations at both locations. There were strong positive correlations between adult populations from light-trap catches and % tiller infestation, and between % tiller infestation and parasitism. The peak period of parasitism by P. diplosisae and A. procerae occurred towards the end of the rainy season in October, coinciding with high level of % tiller infestation. It is concluded that conservation of the parasitoids early in the cropping season (i.e. to improve their synchronization with the host) could become an effective management strategy against AfRGM.

In this study, the effect of the application of three powdery mildew fungicides, namely triadimenol, triadimefon and sulphur, on the African weaver ant (AWA), Oecophylla longinoda Latreille, was evaluated for two seasons in two cashew fields, one each in the Bagamoyo and Mkuranga districts, Coast region, Tanzania. The fungicides were applied at monthly intervals, and the dynamics of AWA were monitored monthly by counting the number of leaf nests per tree and trails on main branches. There were no significant differences among the treatments on AWA at different observation dates in terms of the number of leaf nests and colonization of AWA trails per tree in the two cashew fields studied. In August 2011, for example, the number of leaf nests before application ranged from 7.8 to 9.0 and 13.6 to 14.6 in Bagamoyo and Mkuranga, respectively, and after application, it ranged from 7.8 to 10.0 and 12.4 to 15.2 in Bagamoyo and Mkuranga, respectively. The three powdery mildew fungicides did not have detrimental effects on the abundance of AWA in cashew fields and can, therefore, be used together with AWA as important components of an integrated pest and disease management programme for cashew crops in Tanzania.

A modified technique to extract intact DNA from Aedes aegypti and Anopheles darlingi mosquitoes is presented. The samples were treated initially with proteinase K to digest all proteinaceous matter. For both vectors, the optimum temperature for the protease treatment was 55°C and the best pre-incubation time was 4 h. RNA contamination was eliminated with RNAse treatment. The purity of the DNA was high since the A260/A280 ratio averaged >1.80 for all samples and the quantity of DNA extracted was >1.6 times higher than that using the unmodified procedure. The DNA obtained displayed clear random amplified polymorphic DNA (RAPD) profiles, which indicates that it can be used for polymerase chain reaction (PCR)-based techniques.

The effectiveness of maize (Zea mays L.) planted at different times in a maize–cucumber intercrop to reduce the density of cucumber insect pests was investigated in 2007 and 2008. The cucumber varieties Marketmore and Hybrid F1 were established from seed as a monocrop or intercropped with maize, and with maize established 2 weeks before cucumber (2WBC), the same day with cucumber (SDC) or 2 weeks after cucumber (2WAC). Irrespective of the cucumber variety, there was a significant reduction (over 50%) in the density of insect pests in the cucumber–maize intercrop compared with cucumber alone. Similarly, in both years, fruit damage was significantly lower (about 50%) in the intercropped cucumber, particularly at 2WBC and SDC, compared with cucumber alone. Cucumber fruit yield was significantly higher at SDC but significantly lower at 2WBC relative to the other times. In both years, a relatively higher yield for cucumber was obtained at SDC than at 2WBC and 2WAC. Therefore, a significant control of cucumber insect pests and a higher cucumber yield were obtained when cucumber and maize were planted on the same day.

In the present study, the synergistic effects of Beauveria bassiana (Bals.-Criv. Vuill.) (isolate Bb11) and Bacillus thuringiensis var. kurstaki (Berliner) with neem oil were evaluated in three agroecological zones in Bénin. Four bioinsecticide treatments (neem oil, neem oil and B. bassiana used separately for different target pests, neem oil mixed with B. bassiana and neem oil mixed with B. thuringiensis) were compared with a calendar-based treatment using synthetic insecticides and a control without insecticides. The bioinsecticide treatments were less effective than the calendar-based treatment at controlling cotton pests. There was no difference in yields and the number of damaged bolls in plots under treatments with the four bioinsecticide formulations, suggesting an absence of synergy between neem oil and B. bassiana and neem oil and B. thuringiensis. The numbers of natural enemies in all the bioinsecticide treatment plots and the control plots were similar and higher than those in the calendar-based treatment plots. The highest yield and profitability were obtained with the calendar-based treatment. Screening the compatibility of plant-based products and biopesticides through bioassays is essential for a successful application of their combinations in any integrated pest management strategy.

Laboratory studies were conducted to assess the toxicity and growth-inhibitory activity against Aedes aegypti larvae, of the crude acetone extracts of Polygonum senegalense (Meissn.) leaves, its flavonoid component 2',6'-dihydroxy-4'-methoxydihydrochalcone and the internal tissue flavanol quercetin. The first two showed significantly high insecticidal and growth-inhibitory activity even at low concentrations, whereas quercetin was toxic only at concentrations above 7μg/ml.

A field survey on maize stemborers, stemborer damage, maize plant physical conditions, and maize yield was conducted in eastern Kenya under natural conditions. Chilo partellus was the dominant stemborer accounting for 89.5 % of all borers. Stemborer damage greatly reduced maize yield, with tunnel lengths greater than 20 cm causing a 40 % reduction of potential yield. A 33 % yield loss was found in plants with more than one stemborer exit hole. Each stemborer (at harvest time) was correlated with a 8–10 % yield loss. Good plant physical characteristics significantly increased grain yield. Principle component analysis showed that stemborer damage, plant height and stem diameter were key factors affecting maize grain yield. Regression analysis indicated that one centimetre of stemborer tunnel reduced yield by 3 g/plant. Multiple regression analysis implied a 13.3 ± 1.5 g yield loss (8–10 % of potential yield) due to the damage of a single stemborer. Comparison with average yields in the study area suggested that our results were representative of losses on farmers' fields.

The human body louse aggregates on filter paper impregnated with an aqueous extract of louse faeces. Chemical analysis of the faeces revealed the presence of haemoglobin, xanthine, hypoxanthine, uric acid and ammonium salts. Of all these compounds, only ammonium salts caused marked aggregation of lice. Excretory products of other insects and ticks also failed to induce aggregation. Total faecal material was more attractive than ammonium, and led to greater aggregation of females than of males. Antennectomized lice reacted neither to faeces extract nor to ammonium carbonate solution.

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 progress of the South African Sugar Association Experiment Station's 15-year-old biological control programme against Eldana saccharina Walker is reviewed. Two approaches at controlling this borer, a ‘new association’ and a ‘modified’ classical biological approach are summarised. Constraints identified as limiting the successful establishment of 10 egg, 12 larval and 2 pupal ‘new association’ parasitoids include host incompatibility, climatic incompatibility, poor ecological and biological life history knowledge, incorrect parasitoid searching ability and hyperparasitic tendencies. The 3 egg and 7 larval ‘modified’ classical biocontrol parasitoids which could be reared in the laboratory had constraints such as parasitising ability, different host habitat, differing host behaviours in different habitats and initial host identification difficulties to overcome. Difficulties encountered in this biological control programme against an indigenous pest insect show that biological control is not easy. Knowledge of constraints identified during this programme will hopefully be of use to others embarking on similar projects.

Laboratory experiments using a glass tube arena were conducted to determine the effects of aggressive behaviour of the stemborer, Chilo partellus Swinhoe (Lepidoptera: Pyralidae), on oviposition success and mortality of the parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae). On contacting unparasitised hosts, female parasitoids rapidly oviposited and then retreated from the experimental arena. Hosts exhibited no aggressive behaviour prior to oviposition. However, soon after being attacked, host larvae became more aggressive, spitting at and biting the parasitoids. When Co. flavipes females were introduced toward the head of the stemborer, the parasitoids stung the host near the head and were frequently bitten and killed by the hosts. Parasitoids that were introduced to the host from the posterior end of the abdomen, stung the abdomen and were often able to escape from the host without being bitten. Regardless of whether parasitoids were introduced near the head or the abdomen, they were more often killed by older hosts than younger hosts. Parasitised hosts were more aggressive than unparasitised hosts one hour after the initial parasitisation, but not after 24 hours. Larval saliva of Chilo partellus was found to reduce survival of adult female parasitoids. The aggressive behaviour of Ch. partellus was not effective as a self-defense against Co. flavipes, but is likely to be an important mortality factor of Co. flavipes in nature.

One tactic of importation of natural enemies for biological control of stemborers and other pests is the use of parasite species that have had no previous association with the pest. This ‘novel association’ approach offers the possibility of using parasites that have proven effective against a stemborer species other than the target stemborer pest. Nevertheless, creation of a novel host-parasite association requires that the novel host be ecologically and physiologically equivalent to the ancestral host. Selecting natural enemies based on ecological and physiological equivalence offers the best possibility of temporal, behavioural, nutritional and immunological compatibility in the host-parasite interaction, and reduces the chances of failure with the imported parasite species.

It is known that in citrus orchards, the citrus psyllid Trioza erytreae (Homoptera: Triozidae) preferentially chooses certain varieties for egg laying, feeding and larval development. However, the selection mechanism in citrus nurseries is poorly understood. The aim of the present work was to study in the nursery, the behaviour of T. erytreae with respect to choice of egg laying and feeding sites in three species of citrus, namely Villafranca lemon, Mexican lime and Fremont mandarin. One hundred young plants of each were exposed to the citrus psyllid on the fourth month after germination, and psyllids and pit galls counted every month. The impact of the psyllid's damage on citrus was also assessed. Adults of T. erytreae were highly attracted to the young citrus plants three weeks after the germination of seeds. The average number of adults, eggs and larvae of T. erytreae by plant varied with the particular citrus plant: on young plants, adult, larval and egg populations were highest on lime. Four months later, 100 % of lime, 97% of lemon and 76 % of mandarin plants were attacked by T. erytreae. Those plants attacked shortly after germination were stunted and their leaves greatly deformed. In the absence of pest management in the citrus nursery, citrus psylla can cause the loss of up to 91 % of young plants.

Preliminary observations were made in the attraction of moths of Chilo partellus Swin., Busseola fusca Fuller, Sesamia calamistis Hmps. and Maliarpha separatella Rag. to light traps and to traps baited with virgin females of these species. The observation was conducted from January 1981 to April 1982 at Mbita Point Field Station in western Kenya. M. separatella showed the highest attraction to light traps followed in descending order by C. partellus, E. saccharina, S. calamistis and B. fusca. The mean catches/trap/night in pheromone traps was highest for M. separatella, followed by C. partellus and B. fusca. The period of atttraction of the moths during the night and effect of moonlight on trap catches were also studied. Catches from light and pheromone traps indicated that attraction of C. partellus and M. separatella was greatest between 23:00 and 03:00hr. The effect of moonlight on light trap catches was greater than on pheromone trap catches.

Vector-borne diseases such as malaria, lymphatic filariases, schistosomiasis, leishmaniasis, onchocerciasis, trypanosomiasis, dengue and dengue haemorrhagic fever (DHF), yellow fever and Japanese encephalitis, globally account for suffering amongst more than one billion people, mostly from the developing world. Geographical distribution and prevalence of these diseases have been discussed. In addition to the mortality caused by these diseases, millions of people lead a hopeless life and are socially unable to achieve self-realization and be economically productive, as a result of these diseases. Examples of such economic impact and the costs of these diseases and methods of control have been given. Economic benefits of control of some of these diseases have been discussed. These concepts are of utility when resource allocation for control of these diseases is under consideration.

Because seasonality in tropical habitats is controlled primarily by variations in rainfall rather than variations in temperature, it is frequently less predictable in timing, and spatially more patchy than seasonality in temperate habitats. This constrains the ways in which tropical species can adapt to seasonally adverse conditions, and in particular, may give greater importance to migratory behaviour as a component of seasonal adaptation.

Australian pierid and nymphalid butterflies illustrate these points. The species studied are present as adults during the dry season. Some undergo a reproductive diapause while others breed continuously. Major seasonal shifts in geographic distribution are a conspicuous feature of their biology, except in species whose reproduction is cued directly by rainfall, or are restricted to less seasonal microhabitats. Reproductive diapause is often associated with aggregation and with non-melanic polyphenism. Reasons for spending the dry season as an adult may include the fact that adult food remains available through the dry season even though larval resources disappear, and an improved capacity for opportunistic dispersal before breeding begins. The use of direct rainfall cues to control diapause may exclude non-migratory species from subtropical or temperate regions.