Powders from dry leaves of four plant species: Ficus carica (Moraceae), Eucalyptus globulus (Myrtaceae), Olea europaea (Oleacea) and Citrus limon (Rutaceae), were evaluated under controlled conditions (30±1°C and 70±5% RH), for their biological activity against Callosobruchus maculatus (Coleoptera: Bruchidae), and were compared to a powder from cloves of myrtle Syzygium aromaticum (Myrtaceae) and to eugenol (the essential oil from cloves). Once mixed with seeds of chickpea Cicer arietinum at doses of 1 to 5% (w/w), all the five powders significantly reduced adult longevity. Among these tested botanicals, clove powder was the most toxic as adult survival in treated seeds was less than 24h, even at the lowest dosage of 1%. The powders from dry leaves also reduced fecundity while that from cloves completely inhibited oviposition in C. maculatus. Indeed, the mean number of eggs laid in chickpea seeds treated with powders from dry leaves of the four plant species above varied from 273.2±30.3 to 373.8±58.2 against 401.8±37.9 in the control (untreated seeds). At the highest dose of 5%, all powders significantly reduced the number of emerging adults: 149.3±46.7 in treatment with O. europaea, 139.8±25.1 with E. globulus, 82.8±48.1 with C. limon, 31.5±20.5 in treatment with F. carica and 0.0±0.0 with S. aromaticum. Tests with lower doses (0,1–0,5%) of clove powder revealed that from the dose of 0.2% and above, C. maculatus adults died before laying eggs. Treatments with eugenol at 5μl/50g seeds (v/w), significantly reduced adult longevity (1±0.0 day), the number of eggs laid (0.0±0.0 egg) and adult emergence rate (0.0±0.0 adult), compared to the control used in this test where these parameters are respectively 7.00±0.8 days, 1134.4±204.2 eggs and 745.6±144.9 adults of the first generation.

The effect of different constant temperatures (20, 25, 27, 30 and 35 °C) on life history stages of the Mexican chrysomelid beetle, Zygogramma bicolorata Pallister, fed on the weed Parthenium hysterophorus Linnaeus was investigated to analyse the development and survival of different life stages and the adult sex ratio. Fastest development and maximum survival were recorded at 27 °C. The first instar was the most vulnerable, while the pupa was least vulnerable. For complete development, the lower temperature threshold (t°C) was 18.5 °C and the thermal constant (K) was 480.8 day-degrees. A higher percentage of females was obtained at all temperatures; however, this was unaffected by the temperature regime. This study established that the percentage life span spent by immature stages was similar across all five temperatures, indicating developmental rate isomorphy. 27 °C was the most suitable temperature under controlled abiotic conditions for the propagation of Z. bicolorata, a bioagent for parthenium weed.

Pollinators are important natural agents for fruit and seed formation in most tree crops and the use of appropriate sampling methods is fundamental in studying their population. A study to develop surveying and monitoring protocols for cocoa pollinators was undertaken in Ghana. Yellow, white and blue UV-bright painted pan traps (UVPPT), McPhail traps and motorized aspirators were used to sample pollinators of cocoa for 13 successive months, after 6 days assessment of the effectiveness of the traps and diurnal active period of the pollinators. The peak pollinating period of cocoa by ceratopogonid midges was between 07.00 and 12.00 h, as previously reported. All three methods were effective in sampling ceratopogonid midges with the UVPPT being the most efficient in terms of sampling effort. The number of ceratopogonid midges caught by the yellow-UVPPT was significantly higher than that by blue- and white-UVPPT. The diversity of midges caught could not be determined due to taxonomic difficulties, and thus all the three colours of UVPPT should be used until efficiency in terms of diversity is determined. It is reported here that the meliponine bee Liotrigona parvula Darchen visits cocoa flowers and thus their effectiveness in cocoa pollination should be investigated.

A survey on the occurrence of entomopathogenic nematodes (EPNs) was conducted in selected banana fields from three regions in Tanzania, namely Mbeya (Southern Highlands), Morogoro (Lowland) and Pwani (Coast). The main objective of this study was to isolate EPNs naturally occurring in banana fields in Tanzania and to test their effect on banana weevil (Cosmopolites sordidus Germar 1824). We report for the first time the presence of EPNs in Tanzania where four (4.4%) out of 90 samples contained nematodes in the genera Steinernema and Heterorhabditis. EPNs were only isolated in the coastal region in soils with a high sand content. The virulence of nine EPN isolates was tested against larvae and adults of C. sordidus. All isolates caused mortality of the larval stages, whereas the adults appeared resistant to nematode infection. Larval mortality was found to increase significantly with increasing nematode dose. It was also shown that nematodes were able to penetrate and establish in the banana weevil larvae in increasing numbers with increasing nematode dose. The study indicates the potential for including EPNs in management strategies of banana weevil.

Plant essential oils possess diversified insecticidal properties. Under screening programme of survey of bioactive agents for insect control 31 essential oils from different botanicals (2% in acetone), were studied for repellency and direct toxicity (insecticidal) against laboratory bred houseflies, Musca domestica L. The essential oils obtained from Ocimum gratissimum L., Thymus serpyllum L., Illicium verum Hooks, f., Myristica fragrans Houtt., Curcuma amada Roxb. showed 100% repellent activity, and Acorus calamus L. and Thymus serpyllum L. showed about 40% insecticidal activity. Results were compared with N, N-diethyl-meta-toluamide, dimethyl phthalate, malathion, pyrethrum extract, thymol, mineral oil and piperonylbutoxide. Biochemical studies of these promising oils may emerge new leads in developing future pesticides.

A new plant-feeding species of braconid wasp Allorhogas minimus Centrella & Shaw is described from Heredia Province in Costa Rica. The new species is diagnosed and compared with other species in the genus. This is the first record of an Allorhogas species from fruit galls on Miconia longifolia.

The use of synthetic pesticides among vegetable producers in urban and peri-urban Cotonou, Benin, has been increasing to the extent that certain insect pests have developed resistance to the pesticides. This paper assesses the impact of the farmer field school approach in an integrated pest management (IPM) project that aimed to increase IPM knowledge, adaptation/adoption of IPM options, and appropriate application of pesticides and awareness of related health hazards among vegetable producers in Cotonou. A sample of 54 semi-structured interviews was conducted with the vegetable producers, and a double difference model was used to compare the knowledge and practices before and after the project. The project led to increased knowledge about IPM, which was to some extent adapted into the participants' production systems, although no significant difference was noted for the type of synthetic pesticides used. The producers do adapt their practices when new technologies and practices emerge, but not always in ways that are environmentally sound or healthy.

In southern India, the principal tea pests such as the mites, Acaphylla theae, Calacarus carinatus and Oligonychus coffeae; the thrips, Scirtothrips bispinosus; the aphid, Toxoptera aurantii; and the caterpillars, Caloptilia theivora, Homona coffearia and Cydia leucostoma are attacked by many natural enemies. H. coffearia is efficiently controlled by the ichneumonid, Phytodietus sp., and the tachinid, Palexorista solennis, whilst the eulophid, Sympiesis dolichogaster, affords excellent regulation of C. theivora. The braconid, Apanteles aristaeus, is the chief parasitoid of C. leucostoma, but the efficiency of this species is rather low. The aphiidids, Aphidius colemani, Lipolexis scuttellaris and Trioxys indicus, and several species of coccinellids and syrphids exert tremendous influence on the populations of T. aurantii. No natural enemies of the scolytid stem borer, Xyleborus fornicatus, could be recorded. For the management of mites, pesticides are applied regularly and the widespread usage of broad spectrum acaricides such as dicofol and sulphur is an important reason for the low incidence of predatory mites in tea fields.

Three hundred and ninety-two maize fields in the southern arable zone of Kenya were sampled for lepidopteran cereal stemborers from 1996–2000. Chilo partellus (Swinhoe) was the most abundant stemborer, and was found at all locations with elevations below 1500 m, and at some locations between 1500 and 2300 m. The highest density of C. partellus was in the semi-arid ecological zone of eastern Kenya. Chilo orichalcociliellus (Strand) was found in the lowland southern coastal area, and a few inland sites on the border of Tanzania in southeastern Kenya. Busseola fusca Fuller was dominant in highland areas. In the Lake Victoria Basin, which has an elevation of about 1100 m, B. fusca was dominant at some sites, but overall, C. partellus was more abundant. Sesamia calamistis Hampson was present at all elevations and all locations, but typically at low densities. Eldana saccharina (Walker) was found in two-thirds of the fields sampled in the Lake Victoria Basin. These results are compared with the distributions of the various stemborers in the 1950s to 1960s, as reported in the literature.

Insect pests cause major damage to stored grain and foodstuffs, reducing the products' weight, quality and market value. Eight spices commonly used to add flavour and colour to food were evaluated, singly and in combination, for their contact and fumigant toxicity, repellency and effects on progeny development against the cowpea weevil Callosobruchus maculatus F. and rust red flour beetle Tribolium castaneum Herbst. The powders of large cardamom, turmeric and ginger showed contact toxicity against the two test insects. Green cardamom powder was found to have fumigant toxicity against adults of both insects. Clove powder at 1.5 g/50 g dose showed 100% repellency against adults of T. castaneum. The powders of large cardamom, cinnamon and clove caused complete inhibition of progeny production in C. maculatus and T. castaneum at a dose of 5 g/100 g. A 1:1 mixture of green cardamom and turmeric showed both contact and fumigant toxicity against C. maculatus, while a mixture of clove and large cardamom showed repellency and inhibited progeny development in T. castaneum.

The resistance or susceptibility of sorghum genotypes to damage by the spotted stemborer Chilo partellus (Swinhoe) is commonly measured in terms of leaf damage, deadheart formation and stem tunnelling. Effect of the host plant on the insect survival and development (antibiosis) and the response of the plant to insect damage (tolerance or recovery resistance) are also important parameters for measuring host plant resistance to stemborers. We compared ten selection indices commonly used to select genotypes for tolerance/resistance to various stresses, namely functional plant loss index (FPLI), antibiosis index (ABI), mean productivity index (MPI), mean relative performance (MRP), relative efficiency index (REI), tolerance index (TOL), Fischer's and Maurer's stress susceptibility index (FMSSI), Fernandez stress tolerance index (FSTI), geometric mean productivity (GMP) and Schneider's stress severity index (SSSI). The results suggest that the indices based on grain yield reduction can be combined with those associated with grain yield response and potential under borer-infested and uninfested conditions, since each index assesses different biological mechanisms (such as tolerance, adaptation and/or productivity). Among these, FPLI can be used to differentiate the sorghum genotypes for different components of resistance by taking into account both foliar damage and deadheart formation. GMP, REI and FSTI provided a better discrimination of the stemborer-tolerant genotypes under borer-infested conditions, and were better predictors of grain yield performance than TOL, MPI, MRP, ABI, SSSI, FMSSI and FPLI. A strong association between GMP and REI indicated that both these indices could be used to select for low grain yield loss and high productivity. However, the selection of genotypes with high grain yield potential and adaptation to borer infestation may be achieved by combining selection indices related to the mean grain yield performance under borer-infested and uninfested conditions (GMP and REI), and low levels of grain yield loss under borer infestation.

The fitness of Helicoverpa armigera (Hübner) was determined using demographic studies on the F1 generation that survived after exposure to four sublethal doses (LC50, LC30, LC20 and LC10) of imidacloprid. The effects were assessed on the surviving individuals emerged from sixth-instar larvae that had ingested imidacloprid-treated chickpea pods. Age-specific parameters were found to be highest with the commencement of age and gradually decreased with the progression of age in both the treated and non-treated groups. Survivorship was reduced to 37 days after exposure to the sublethal dose of LC50 when compared with 42 days in groups not exposed to the insecticide. The highest number (17%) of unhatched eggs was recorded in insects treated with the LC50 dose of imidacloprid, whereas 98% of the eggs hatched in the unexposed group. The potential fecundity of the F1 generation females was reduced to 330 eggs/female/generation when treated with the LC50 dose compared with that of the unexposed females. The intrinsic rate of increase was found to be least in insects exposed to the LC20 dose (0.0355 females/female/day) and highest (0.0470) in the unexposed group. It took 38.83 days for H. armigera to complete one generation in the unexposed population, while this was reduced to 33.94 days after exposure to the sublethal dose of LC50. The longevity of adults decreased when the larvae were exposed to the sublethal dose of imidacloprid. The developmental time of pre-pupae and pupae significantly decreased and was least when exposed to the highest sublethal dose of the insecticide. Thus, at sublethal doses, imidacloprid caused a significant reduction in the survival and fecundity as well as increased mortality of H. armigera in the subsequent generation after exposure to the insecticide. In conclusion, imidacloprid can be successfully incorporated into integrated pest management of H. armigera.

Cowpea (Vigna unguiculata (L.) Walp) is an important food staple in sub-Saharan Africa. The legume pod borer Maruca vitrata Fabricius is one of the key pests of cowpea as the larvae feed on the tender parts of the stem, peduncles, flower buds, flowers and on pods of the plant, causing significant yield losses. Understanding the seasonal and geographical patterns of M. vitrata is essential for the establishment of effective pest management strategies. Sites in three ecological zones in Burkina Faso were sampled for the presence of M. vitrata adults and larvae both during and outside of the cowpea-growing season. Our data suggest that M. vitrata do not maintain a permanent population in the Sahelian or Sudano-Sahelian zones, but emigrate from the Sudanian zone where M. vitrata populations evidently may occur throughout the year.

The sweet potato weevil (SPW), Cylas formicarius, is a serious pest of sweet potato in Australia and Papua New Guinea. Ten strains of Metarhizium sp. isolated from Australian soil samples were evaluated for their growth characteristics and screened for virulence to adult SPW under laboratory conditions. All isolates except QD62 (48.6%) had moderate to high germination (66–97%), and all took 2 to 4 days to sporulate at 25 °C. The optimal temperature for radial growth for the majority of isolates was 30 °C, and there was a significant interaction between isolate and temperature (P< 0.05). Isolate QS155 showed the fastest radial growth at 30 °C. The internal transcribed spacer sequences showed slight variations among the isolates; however, all isolates were shown to be Metarhizium anisopliae. Isolates varied greatly in their virulence. At 10 days after inoculation (DAI) by immersion in a suspension of 1 × 107conidia/ml, 9 of the 10 isolates were virulent, causing 80–100% mortality of adult SPW. Only two isolates (QS001-6 and QS155) caused more than 50% mortality at 5 DAI. In dose-mortality bioassays, isolate QS155 had the lowest 20-day LC50 and LC90 values; however, there were no statistically significant differences in mortality among the three most promising isolates tested (QD66, QS001-6 and QS155). These results show that M. anisopliae isolate QS155 has potential as a microbial control agent for SPW, and that further evaluation under glasshouse and field conditions is warranted.

A survey of the natural enemies of the main malaria vector in Kenya, Anopheles gambiae Giles, revealed the occurrence of a fungal pathogen in field populations of mosquito larvae. Light and scanning electron microscopy was used in the examination of sporangia of the fungus in determining its identity as Coelomomyces indicus Iyengar (Order: Blastocladiales; Family: Coelomomycetaceae). The resting sporangia were found in the thoracic and abdominal cavities of the larvae. A mortality of 63% or higher was found to occur among the larvae of A. gambiae in a two season observation along the Kenyan coast. The authors stress the need for more intensified ecological and laboratory studies aimed at developing C. indicus as a biocontrol agent.

Hand-stinging and mass exposure methods of rearing the parasitoid Cotesia flavipes Cameron (Hymenoptera:Braconidae) on the stem borer host, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), were compared. The proportion of hosts successfully parasitised, progeny production, proportion of female progeny, and host mortality did not differ between the two methods. However, there was evidence of superparasitism of mass-exposed hosts. Releases of C. flavipes as adults and as cocoons were both effective methods for field colonisation of the parasitoid. A device for the release of C. flavipes in the cocoon stage is described.

Dengue has become the fastest-growing mosquito-borne disease in Sri Lanka and the control of the vectors, Aedes aegypti Linnaeus and Ae. albopictus Skuse, is the most effective way of controlling the disease. A detailed study on vector prevalence has not been recorded from Sri Lanka. Therefore, the present study was undertaken to study the prevalence of both vectors in four semi-urban study sites in two of the most affected districts, namely Kandy (wet zone) and Kurunegala (intermediate zone), by conducting egg surveys (using ovitraps) and larval surveys from June 2007 to May 2008. A total of 82,524 eggs and 2658 larvae of Ae. aegypti and Ae. albopictus were collected. A total of 3699 potential breeding habitats were examined. Ovitrap and larval indices (house, container and Breteau) showed that all four areas are at epidemic risk, especially due to a high abundance of Ae. albopictus. The highest numbers for both the species were from the Kandy sites where dense vegetation, high rainfall and low temperature prevailed. The results showed a high mortality rate during the egg-to-larva transition, suggesting that conducting an egg survey alone would overestimate the vector abundance and the disease risk. For Ae. albopictus, the monthly mean number of eggs showed positive relationships with relative humidity in both districts and with rainfall in the Kandy District. The number of dengue cases in the area had no positive relationships with the abundance of eggs or larval density indices. Discarded receptacles were the most preferred breeding habitat for these dengue vectors. Since the attractiveness (inferred by the calculated risk factors) of most of the breeding habitats was very high, elimination of these breeding sites is essential for the success of dengue control programmes.

In the present study, immediate and trans-generational effects of parental diets (i.e. abundant and scarce) were investigated in a ladybird beetle Anegleis cardoni (Weise). Prey scarcity prolonged pre-oviposition period and reduced fecundity and egg viability. Reduced survival and developmental rate of progeny was recorded under prey-scarce conditions. The progeny of parents reared under prey-scarce conditions developed more slowly than that of those reared under prey-abundant conditions, regardless of the progeny diets. This study indicates the existence of parental diet effects on progeny survival and developmental attributes.

Stingless bees are little-known organisms but important plant pollinators in Bwindi Forest. They risk disappearance, as with other pollinators and seed dispersers, as a result of pesticide and herbicide poisoning, habitat alteration, invasion by alien species (plant and animal) and insularization of habitats. Bwindi Impenetrable National Park forest has five species of stingless bees in two genera (Meliponula and Hypotrigona). The conservation of pollinators in Bwindi needs to be urgently addressed, and among the required measures are studies on plant–pollinator relationships. The study also demonstrated the accuracy of Abayanda indigenous systematic knowledge.

Honeybees are of critical importance in Africa for both ecological and economic reasons. Their contribution to floral biodiversity and conservation, by virtue of their pollination of indigenous flowering plants is unknown, but certain to be considerable. Economically, honeybees are critical for the pollination of a host of commercial crop plants as well as being the source of energy and livelihood for many thousands of mostly small-scale beekeepers. In the past, honeybee pests and problems have been of limited importance in Africa. More recently, however, an increasing number of exotic diseases and pests as well as home-grown problems threaten honeybees, beekeeping and honeybee-pollination in Africa. Two problems in South Africa, the capensis problem and varroa mites, have severely curtailed beekeeping in that country and may well have impact on bees and beekeeping throughout the continent.