Perovskia abrotanoides Karel is a wild growing plant in Iran and has been used in traditional Iranian herbal medicine. The present study was conducted to investigate chemical composition and fumigant toxicity of the essential oil from P. abrotanoides against Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). Dry flowering aerial parts of the plant were subjected to hydrodistillation using a modified Clevenger-type apparatus. The composition of the essential oil was analysed by gas chromatography (GC) and GC mass spectrophotometry. Twenty-four compounds representing 98.8% of total oil were identified. The predominant components in the oil were camphor (28.38%) and 1,8-cineole (23.18%). Fumigant toxicity was tested against 1- to 7-day-old adults of S. oryzae and T. castaneum with five replications at 25 ± 1 °C and 65 ± 5% relative humidity in dark conditions. The mortality was increased with concentrations of 32, 161, 322, 483 and 645 μl/l air and with exposure time from 2 to 15 h. The lowest concentration (32 μl/l air) of the oil induced 100% mortality of S. oryzae and T. castaneum after 15 and 8 h exposure, respectively. The oil at 322 μl/l air caused 100% mortality for S. oryzae and T. castaneum within 13 and 7 h exposure, respectively. At 645 μl/l air, the LT50 values (lethal time for 50% mortality) were 8 and 2.84 h for S. oryzae and T. castaneum, respectively. In the probit analysis, LC50 values (lethal concentration for 50% mortality) showed that T. castaneum (LC50 = 11.39 μl/l) was more susceptible than S. oryzae (LC50 = 18.75 μl/l). The essential oil of P. abrotanoides can play an important role in stored grain protection and reduce the need for the same, and also the risks associated with the use of synthetic insecticides.

The biology of Typhlodromips swirskii (Athias-Henriot), Typhlodromus athiasae Porath and Swirski and Paraseiulus talbii (Athias-Henriot) was studied using Aculops lycopersici (Massee) active stages as food source. For T. swirskii, development was faster and reproduction was higher than in T. athiasae. Survival of immatures of P. talbii was low on A. lycopersici and all failed to develop to adulthood. A total of 35.4 and 30.3 eggs per female, respectively, were obtained when T. swirskii and T. athiasae were fed on active stages of the tomato rust mite. A diet of A. lycopersici provided the shortest female longevity and highest mean total fecundity, which resulted in the highest net reproductive rate (Ro = 26.785), intrinsic rate of natural increase (rm = 0.235) and finite rate of increase (λ = 1.265) for T. swirskii. The mean generation time ranged between 13.97 and 17.85 days for T. swirskii and T. athiasae, respectively.

The termite Macrotermes michaelseni (Sjöstedt) builds conical earth mounds with no external openings. The structure of the nests is described. The fungus combs and the nursery are in separate parts of a single hive chamber, and thus occupy the same air space. A closed system of inter-connected passages in the mound facilitates loss of metabolic heat to the atmosphere.

Mango (Mangifera indica L.) is a well-recognized fruit of economic and nutritional importance to smallholder farmers across Africa. Production and marketing of this fruit is, however, severely hampered by fruit fly infestation that is responsible for enormous fruit losses. In Kenya, control of this pest is primarily dependent on the use of chemical pesticides, a strategy that has been shown to be ineffective. Although the recently introduced fruit fly integrated pest management (IPM) package developed by the International Centre of Insect Physiology and Ecology (icipe) has proved to be effective against this pest, there is little demonstrable investigation on its adoption to assess the factors likely to influence its acceptance among producers. A household survey was conducted among 805 randomly sampled mango farmers, and a negative binomial regression model was applied to the data in order to identify the factors influencing the intensity of the adoption of the fruit fly IPM package. Results revealed that 58.5% of the sampled mango farmers adopted at least one component of the fruit fly IPM package. Empirical results indicated that education of the household head, number of mature mango trees planted, keeping records of mango enterprise, use of protective clothing during spraying and participation in the IPM training at demonstration sites have a positive influence on the intensity of the adoption of the fruit fly IPM package in Embu, situated in eastern Kenya.

An artificial diet for mass rearing of the tobacco caterpillar Spodoptera litura (Fabricius) from the neonate to adult stage was developed at 27±1°C, 65±5% RH and 16:8 h scoto/photo-phase regime. The diet ingredients consisted of wheat germ (26.0 g), kidney bean flour (51.3 g), chickpea flour (56.0 g), yeast powder (31.6 g), casein (15.2 g), l-ascorbic acid (3.2 g), cholesterol (0.5 g), two multivitamin multimineral capsules, one vitamin E capsule, ABDEC drops (2 ml), castor oil (1 ml), methyl-p-hydroxybenzoate (1.8 g), sorbic acid (1.3 g), streptomycin sulphate (0.25 g), formaldehyde solution (2 ml), agar–agar (16.4 g) and 820 ml distilled water. The new artificial diet successfully supported the growth and development for more than ten generations with enhanced reproductive potential. The mean biological parameters based on rearing of ten continuous generations showed higher pupation (89.2%), emergence (97.2%), survival (86.6%) and fecundity (2486.2 eggs) as compared to the most preferred natural food, castor leaf whose respective recorded values are 80, 75, 60% and 480 eggs. The cost of 1 l of the diet was approximately US$ 2.00 only, on which 200 neonate larvae can be reared. The artificial diet developed is suitable for mass rearing S. litura successfully throughout the year for laboratory and field experimentation as well as for commercial production of nuclear polyhedrosis viruses (Sl NPV).

Protecting vegetables with a screen in peri-urban areas of tropical countries could reduce or even prevent often indiscriminate insecticide applications by small-scale farmers. The advantages of such an approach are protection of human health by reducing insecticide sprays, reducing environmental pollution from insecticide residues and increasing effectiveness of crop protection. Tunnel screens are well adapted to farmers cultivating intensively on small plots. Two trials were conducted to test the ability of screened tunnels to protect Brassica oleracea crops. The first was carried out on-station and the second in partnership with three farmers in Cotonou, Benin, West Africa. Tunnel screens impregnated with deltamethrin were found to be particularly well adapted to protect young plants in seedling nurseries against infestations by the aphid Lipaphis erysimi (Kaltenbach). The number of diamondback moth Plutella xylostella (Linnaeus) and borer Hellula undalis (Fabricius) on cabbages protected with the tunnel screen was significantly lower than that of plots conventionally treated with insecticides. The tunnel screen was not efficient against the armyworm Spodoptera littoralis (Boisduval) which laid eggs on the screen. After planting out, the use of a temporary screen from 1700 to 0900 h gave better control against pests than the use of a permanent screen possibly due to the impact of natural enemies during the day. The field trials showed that the protection of cabbage with a tunnel screen could be an economically viable method. The costs of pesticides are on average US$ 45 per 100 m2 for one crop cycle compared with US$ 24 per 100 m2 for tunnel screen material (assuming that this material can be used for 10 consecutive crop cycles). In addition, there are environmental benefits from a reduction of pesticide use. Farmers will have to cope with the initial investment for the screen material, which is, however, very cost-effective and locally available. Tunnel screens for vegetable protection can be easily combined with other integrated pest-management techniques.

Defensive behaviour is one of the principal ways vertebrate hosts regulate the blood-feeding success of vector insects. Intrinsic variation in the intensity and efficiency of this biting avoidance behaviour depends on host: (1) species, (2) size, (3) age, (4) health and (5) individuality. In this paper we summarize data on the relative importance of each of these host-associated factors in regulating mosquito feeding and transmission of mosquito-borne diseases.

The government's cocoa spraying gangs in Ghana treat about two million hectares of the crop against black pod disease and mirids, the key insect pests of cocoa in West Africa, each August through to December, based on recommendations issued in the 1950s. A few cocoa farmers use additional pesticides. We studied the temporal distribution of two important mirid species, Distantiella theobroma (Dist.) and Sahlbergella singularis Hagl., in 1991, 1999, 2003 and 2012 to determine the appropriate timing for the application of control measures in current farming systems. There was a significant correlation between mirid abundance and pod availability on trees, as well as the number of basal shoots and the cocoa variety grown. Mirid populations peaked between January and April and from September to October. Surveys (interviews and focus group discussions involving over 300 farmers in 33 cocoa-growing districts) on pesticide use, sources of recommendations, and perceived successes and failures of current cocoa pest treatments suggested that the 1950 recommendations on the timing of insecticide application need revising.

The sugarcane aphid Melanaphis sacchari (Zehnt.) has become a serious pest of sorghum, particularly during the post-rainy season in India and East and Southern Africa. Therefore, we tested a number of techniques to screen sorghum genotypes for their resistance to M. sacchari. Infesting the plants with aphid-infested leaf cuttings and covering with a nylon net was effective in screening sorghum genotypes for their resistance to M. sacchari. Sprinkling the plants with aphids (filled in an 0.5 ml eppendorf tube) in the greenhouse was also used to confirm whether the resistance of genotypes selected is less susceptible to the aphids under natural infestation. Nine genotypes (Line 61510, ICSV 12001, ICSV 12002, ICSV 12003, ICSV 12004, ICSV 12005, SLR 41, PU 10-1 and DJ 6514) exhibited moderate levels of resistance to M. sacchari. These genotypes also exhibited a lower rate of aphid multiplication in the clip cage and leaf disc assays. The rates of aphid multiplication were lower on the genotypes IS 21807, IS 40615, IS 40616 and IS 40618 than on the susceptible check, Swarna in the clip cage assay under the field conditions. Also, lower rates of aphid increase were also recorded on IS 21807 and IS 40615 in the leaf disc assay under laboratory conditions. Some of the genotypes that exhibited resistance to aphid damage under field conditions showed comparatively higher rates of aphid increase than the susceptible check, Swarna in the clip cage assay, indicating that antixenosis could be one of the components of resistance to M. sacchari in these genotypes. Therefore, the clip cage assay could be used to gain further understanding of the mechanisms of resistance to M. sacchari. There is a need to assess the role of antixenosis and colonization in genotypic reaction against M. sacchari to identify the lines with different mechanisms of resistance to this pest. The results suggested that the nylon net technique could be used to screen sorghum genotypes for resistance to M. sacchari. The genotypes exhibiting resistance to M. sacchari can be used to develop aphid-resistant sorghums for sustainable crop production.

Crop pollination by wild pollinators is an ecosystem service of immense value to modern agriculture. Pollination by wild insects is under-researched in the tropics, where many crops may require or benefit from wild pollinators. Papaya is a dioecious tree crop widely cultivated throughout the tropics. In East Africa, papaya is an important component of rural smallholder farming systems. Traditional agricultural systems are currently under stress due to landscape degradation. These trends are of special concern with respect to pollination services provided by wild insects. Investigation of the role of hawkmoths as pollinators of papaya on subsistence farms in Kenya was conducted over a period of 3 years. Hawkmoths were the most abundant and reliable visitors to both ‘female’ pistillate and ‘male’ staminate papaya flowers. Hawkmoths accounted for >95% of legitimate visits and xenogamous pollination of papaya flowers. Hippotion celerio, Nephele comma and Agrius convolvuli were the main pollinators. Sites in two districts with similar climates and natural vegetation, but different levels of habitat degradation were chosen for comparison of pollinators and pollination services. Hawkmoth abundance and visitation rates declined sharply with increasing distance of natural habitat patches from the crop. Fruit set was also reduced at sites with high levels of disturbance/poor agricultural practices. Natural habitat containing larval food plants and other nectar resources for hawkmoths therefore supports adjacent cultivated papaya with pollination services. Understanding the links between wild biodiversity, in this case pollinating hawkmoths, and agricultural productivity can help bridge the gap between agricultural development and biodiversity conservation.

Maize is the major food crop in Kenya, where 2.3 million tonnes are produced annually to feed an estimated 28.6 million people (79 kg/person p.a.). Population growth in the country is high (2.9 % p.a.), resulting in increased pressure on arable land and, consequently, increased pest pressure on crops. Stemborers are one of the most important pests of maize. Previous research with artificial infestation established clear links between damage factors and yield losses. These results, however, cannot be extrapolated to estimate crop losses in farmers' fields under natural infestation. Due to lack of field data, farmers' (often subjective) estimates of losses under natural infestation and the incidence of infestation were used to estimate maize yield losses for each of Kenya's major agroecological zones. The yield loss was estimated to be 12.9 %, amounting to 0.39 million tonnes of maize, with an estimated value of US$ 76 million. High-potential areas have relatively low crop loss levels (10–12 %), while the low-potential areas have higher losses (15–21 %). Taking into account the higher yield of the former areas (more than 2.5 t/ha), the loss per hectare is remarkably constant, between 315 and 374 kg/ha, except for the dry mid-altitude zones, where losses total approximately 175 kg/ha. The value of these losses is estimated at US$ 61–75/ha and US$ 34/ha, respectively. Such estimates are useful for setting research and extension priorities.

Cocoa (Theobroma cacao L.) is an important foreign exchange earner for Ghana. However, production is constrained by a high incidence of pests and diseases. Based on farmers' needs, this study focused on the control of capsids, mainly Sahlbergella singularis Haglund and Distantiella theobroma (Distant) (both Hemiptera: Miridae). Annual crop loss caused by capsids is estimated at 25–30%. To control capsids, formal research recommends application of synthetic insecticides four times between August and December. However, farmers hardly adopt this recommendation, which they consider unsuitable for their conditions and context. Three alternative control methods were tested with farmers: mass trapping, using sex pheromones; applying crude aqueous neem Azadirachta indica A. Juss. (Meliaceae) seed extract (ANSE) and using the predatory ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) as a biological control agent. Contrary to most previous reports, studies on temporal distribution of cocoa capsids indicated that the population peaked in March. ANSE was effective against capsids and other cocoa insect pests and did not affect the predatory ant. When O. longinoda occurred in high numbers, capsid incidence was low. Shade did not influence ant or capsid abundance significantly. ANSE caused 100% mortality of capsids in cage and 79–88% in field experiments. The sex pheromone was as effective as ANSE or ants in suppressing capsids. All the three methods were effective and compatible; hence, they can be used in an integrated pest management strategy for cocoa, including organic production in Ghana.

Tea is prepared from the tender leaves and buds of Camellia sinensis (L.). In sub-Himalayan tea plantations of North-East India, different management practices are followed to protect the tea crop against different sucking insect pests such as Helopeltis theivora (Hemiptera: Miridae), Empoasca flavescens (Homoptera: Cicadellidae) and Scirtothrips dorsalis (Thysanoptera: Thripidae). Most plantations are managed conventionally through the use of different organo-synthetic insecticides, whereas some are managed organically by using herbal and microbial insecticides. In conventional tea plantations, organo-synthetic insecticides of different functional groups (organochlorines, organophosphates, synthetic pyrethroids and neonicotinoids) are routinely applied round the year to keep the sucking insect pest populations under control. A variety of defence mechanisms, including enzymatic detoxification systems (carboxylesterases, glutathione S-transferases and cytochrome P450 monooxygenases), physiological tolerance and behavioural avoidance, protect insect herbivores from these hazardous compounds. Insect pests have evolved mechanisms to degrade metabolically (enzymatically) or otherwise circumvent the toxic effect of many types of chemicals synthesized as modern insecticides. The extent to which insects can metabolize and thereby degrade these toxic or otherwise detrimental chemicals is of considerable importance for their survival in an unfriendly chemical environment. These mechanisms continue to evolve as insects attempt to colonize new plant species or encounter newer molecules of synthetic insecticides. The level and type of detoxifying mechanisms differs greatly, which, therefore, results in varying toxicity among different stages, species and populations. Variation in detoxifying enzyme activity is responsible, in part, at least for the selective toxicity of different insecticides, the development of resistance to insecticides and the selection of host plants. Overexpression of these detoxifying enzymes, capable of metabolizing insecticides, can result in higher levels of metabolic tolerance/resistance to synthetic insecticides.

Maize pests feeding on grains can transmit with their movement fungi harmful to human and animal health. The aim of the present work was to study the immigration and the dynamics of storage pests in traditional African maize granaries and the fungal spectrum associated with these insects. Treatments were (i) maize cobs protected just after pollination with gauze and stored thereafter, and (ii) unprotected maize cobs as controls. Eight different species of insects were identified in stores. No Prostephanus truncatus (Horn) was found in ‘protected’ maize during the 6 months of storage, but their mean number reached 239 individuals per kilogram after just 3 months of storage in the ‘unprotected’ stores. Similarly, significantly more Sitophiluszeamais (Motschulsky) were recovered from the unprotected than the protected maize treatment. Nine fungal species were found to be associated with the storage insects. On ‘non-protected’ cobs the genus Fusarium (36.05%) was the most frequently identified, followed by Penicillium (23.50%), Rhizoctonia (5.65%) and Aspergillus (3.95%). On protected cobs, Rhizoctonia sp. was most frequent (16.76%), followed by Fusarium spp. (16.62%), Penicillium spp. (8.24%) and Aspergillus spp. (2.33%). The toxigenic species encountered were Aspergillus flavus Link, Aspergillus parasiticus Speare and Fusarium verticillioïdes (Sacc.). Cathartus quadricollis (Guérin) appeared to carry more fungi towards the store, mainly Penicillium spp. (51.47%), Aspergillus spp. (46.56%) and Fusarium spp. (32.01%). Storage pests, in particular C. quadricollis and S. zeamais, play an important role in the contamination of maize with fungi, especially those that produce toxins.

This bibliography on rice leaffolders contains 886 published and unpublished references for the period 1854 to June 1987. References are arranged alphabetically by the name of author and also classified by subjects. A distribution map, tables of alternate host plants, outbreaks, resistant rice varieties, resistant wild rices, natural enemies and developmental stages, and a brief description of current status of the leaffolders are also provided.

Populations of the whitefly, Bemisia tabaci collected from the Americas and the Caribbean Basin were examined for non-specific esterases and for the ability to induce characteristic phytotoxic disorders in key assay species as a means of investigating biogeographic diversity. Esterase markers were used to detect polymorphisms among regional B. tabaci populations and to establish the present distribution of B. tabaci biotypes in the region. The A biotype occurred only in contiguous locales in northern Mexico and the southwestern US, while the B biotype was present throughout much of the Caribbean Basin and the US, and in Brazil. Distinct C and D type esterase markers were observed for Costa Rican and Nicaraguan B. tabaci populations, respectively. The 0 or null type population was collected only from Jatropha gossypifolia (L.) in Puerto Rico. Laboratory colonies of the A and the B biotypes were almost equally sensitive to an organophosphate, profenofos. The B biotype was more resistant to a pyrethroid, permethrin, suggesting the existence of a biotype of fi. tabaci, with a history of exposure to pesticides with a pyrethroid-based chemistry. In mating studies involving reciprocal crosses between the A and the B biotypes, very few F, female progeny were produced, indicating either minimal or non-existent reproductive compatibility between these haplo-diploid B. tabaci populations, presently considered to be the same species. Evidence is presented for the recent and widespread introduction, and subsequent spread of the B biotype throughout the US, the Caribbean Basin, and other proximal locations.

Mosquito traps known as Mbita traps made from modified bednets according to a design developed in Kenya were compared with Centers for Disease Control (CDC) light traps for their ability to catch anopheline and culicine mosquitoes in several different villages in northern Tanzania. The results confirmed those recently reported in Kenya, that Mbita traps catch significantly fewer mosquitoes than CDC traps. Statistical analysis using a Poisson log linear model with random effects for the trap counts showed that the ratio of the catches with the two types of trap was not consistent in the different villages. Thus, we doubt whether the Mbita trap would be a reliable substitute for CDC traps. In one trial, the catches made at different hours of the night with the two types of trap indicated that in villages where insecticide treated nets (ITNs) had been used for some years, somewhat more of the Anopheles biting occurred early and late in the night, whereas in villages with no history of ITN use, biting was concentrated in the middle of the night. This suggests that behavioural adaptation to avoid contact with ITNs may be beginning to evolve.

The diamondback moth, Plutella xylostella (L.) is the major insect pest of cabbage crops in Togo and Benin. For control, farmers very often resort to spraying chemical insecticides at high dosages with frequent applications. Bioassays were carried out on three populations of P. xylostella, two from Togo (Kara and Dapaong) and one from Benin (Cotonou), to assess their level of susceptibility to currently used insecticides. A reference strain of P. xylostella from Matuu in Kenya was used as a control. In the laboratory, three insecticide representatives of different chemical families (deltamethrin, chlorpyrifos ethyl and spinosad) were assayed against third instar larvae of P. xylostella. Results revealed that P. xylostella populations from Dapaong, Kara and Cotonou were more resistant to deltamethrin (13 to 59-fold at LC50 level, 149 to 1772-fold at LC90 level) and chlorpyrifos ethyl (5 to 15-fold at LC50 level, 9 to 885-fold at LC90 level) than the reference strain. Spinosad was more toxic to P. xylostella populations than the other insecticides with LC50 and LC90 values less than 1 µg/ml and 15 µg/ml, respectively. However, the population from Cotonou appeared significantly more resistant to spinosad compared to the reference strain. These results are discussed in the light of developing an integrated pest management strategy for reducing the selection pressure of spinosad.

The literature on African pollination biology is reviewed. It is found that relatively little work has been done on pollination biology in Africa, and a very small proportion of pollination relationships has so far been studied. Much of the research which has been done is of an evolutionary nature. Very little work has been conducted at the community level and comparatively little applied work, either to agriculture or conservation, was encountered. Most research has been conducted in South Africa, in particular, from the Cape region, which is the only part of Africa for which a reasonably comprehensive body of work on pollination biology exists. In a number of instances results of African studies challenge conventional understanding of pollination biology. It is argued that as more work on pollination is done in Africa, more differences between African systems and the rest of the world, particularly the North temperate regions will be found and changes to the overall conceptualization of pollination systems in different ecosystems are likely to ensue. A more thorough understanding of pollination biology would also make an important contribution to food security and conservation of biodiversity on the continent. Scientists working in fields other than pollination biology, and amateurs, should be encouraged to contribute to the groundwork of African pollination biology by the documentation of pollination relationships.

The distribution of 31 Glossina spp. and subspecies belonging to fusca, palpalis and morsitans groups is given for 38 African countries. The natural hosts of 17 tsetse species and subspecies from many areas within different regions of Africa are also given. These were collated from the results of both published and unpublished work, for the period 1953 to 1991 inclusive, comprising altogether 47, 697 bloodmeals. This review is aimed to provide current knowledge on the distribution as well as the natural hosts of tsetse.