A comprehensive review of the major investigations on the biology and ecology of ticks of Africa reported in scientific journals in the decade 1980–1989 is undertaken. While there have been remarkable advances within the decade on research on feeding habits and patterns of ticks as well as diurnal and seasonal activities, many important areas of research were neglected. These include tick embryogenesis, development and survival under natural conditions, tick modelling, the phenomenon of host's natural resistance to tick infestation, pheromone and biochemical studies and field sampling of ticks. The review also shows that laboratory studies on tick biological systems are scanty in East Africa and the need for greater tick ecological research in West Africa is stressed.

The review shows that in the decade 1980–1989, exotic Bos taurus breeds were predominantly used for experimentation on African ticks and the need to change focus to indigenous B. indicus cattle breeds for experimentation is highlighted. Attention is also drawn to the importance of researchers on African ticks to undertake long term sustainable research with clearly defined goals which can have quantifiable impact on tick control in Africa.

Agricultural treatments mainly against cotton and rice pests put a considerable insecticide pressure on larvae and sometimes adults of several vector species. Resistances to compounds which had never been used for public health, but were currently employed in agriculture were observed among vectors. It was also noticed that resistance level in some vector species was linked to the quantity of the compound used in the same area against crop pests.

Resistance in Anopheles gambiae in Africa, in An. albimanus in Central America, in An. culicifacies and An. aconitus in South East Asia, in An. sacharovi in Turkey, in Culex tritaeniorhynchus in the Far East as well as the DDT resistance in Simulium damnosum in West Africa, seem to be associated with the agricultural practices.

On the other hand, resistance did not develop in species which, due to their ecology, were not in contact with agricultural insecticide even in areas where DDT was applied for more than 20 years in house spraying. This is the case of An. dirus and An. minimus in Thailand and An. darlingi South America.

However several important factors like Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, have developed resistance for which agricultural treatments cannot be held responsible. It would be worth saying that the rise in malaria in certain countries, such as India, is only due to the increase of insecticide in agriculture after the “green revolution”.

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.

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.

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.

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 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.

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.

Little is known about the efficacy of sampling methods for monitoring bee communities in agricultural landscapes in sub-Saharan Africa, in general, and in Uganda, in particular. To provide baseline information on the effectiveness of different sampling methods, 26 sites with varying landscape characteristics were sampled in 2006 in agricultural landscapes in Uganda. Bees were sampled using line transect count, coloured pan trap and hand net methods. In total, 80,883 bee individuals were collected. Totals of 59, 314 and 559 bee species were recorded in transect counts, pan traps and hand nets, respectively. Thus hand nets captured the most species overall. There were few species that overlapped across the three sampling methods. Wild bees were significantly more abundant in yellow pan traps than in blue or white ones. In contrast, bee species richness was significantly higher in blue pan traps than in white or yellow pan traps. Overall, pan-trapping was found to be a complementary method to hand-netting for monitoring bee communities in Uganda.

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.

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.

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.

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.

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.

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.

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.

Host preference studies were conducted on Trichogramma sp. nr. mwanzai at 25 ± 2°C, 40–60% r. h. In the laboratory, using eggs of C. partellus, B. fusca, E. saccharina, S. cerealella and B. mori in choice and no-choice tests. Adults emerged within 9–10 days; ca. 70% parasitoids of both sexes emerged and mated between 0800–1000 hr, with a peak at 0800 hr. There was no significant difference (P < 0.05) between the number of progeny per female from eggs of C. partellus (33.9 ± 9.2), B. fusca (30.1 ± 4.5) and S. cerealella (30.9 ± 9.9) in no-choice tests, but progeny production was significantly less from E. saccharina and no parasitoid emerged from B. mori. In host age selection tests on C. partellus, there was no significant difference (P < 0.05) between the number of offspring per female from eggs of age groups 0–2 days; offspring of day 3 were significantly less, and no parasitoid emerged from day 4 eggs. Up to 4 (mean, 1.9 ± 0.6) adults emerged from a single egg of C. partellus. Since mass rearing technology exists for C. partellus and is available at ICIPE, it was concluded that day 0–2 eggs of this borer are more suitable for mass production of T. sp. nr. mwanzai.

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.