Aquatic larval habitat conditions influence the development, fitness and vectorial capacity of mosquitoes. In turn, human activities can influence these conditions and shape mosquito vector distribution, thus affecting pathogen circulation and transmission. We measured environmental factors (chemical and microbial) in mosquito larval habitats and evaluated their potential as predictors for the occurrence of different mosquito species in an arbovirus and malaria endemic region of western Kenya. We found significantly greater proportions of Aedes aegypti mosquito larvae in ammonium and phosphate rich habitats, suggesting that fertilizer usage could potentially increase aquatic habitat suitability and Aedes vectored disease transmission. Anopheles gambiae larval habitats correlated significantly with higher temperatures. However, none of the Culex species’ habitats correlated with investigated variables, indicating greater larval plasticity compared to Aedes or Anopheles. Profiling of bacterial communities by 16S rRNA pyrosequencing revealed Proteobacteria, Bacterioidetes and Firmicutes as the major bacteria phyla present in mosquito aquatic microhabitats. Although there were no correlations between microbiota composition or diversity and larval species abundance, the dominant genera of microbes detected in larval habitats were reported in larval and adult mid-guts, suggesting that bacteria acquired from the larval habitats are transmitted to adult stages. This study identified the chemical and bacterial composition of aquatic microhabitats that are conducive to the development of different mosquito vectors in western Kenya. This information can inform potential vector control strategies by assessing management of breeding sites based on likely exposure to fertilizer, light and bacterial fauna.

Methyl isonicotinate is one of several patented 4-pyridyl carbonyl compounds being investigated for a variety of uses in thrips pest management. It is probably the most extensively studied thrips non-pheromone semiochemical, with field and glasshouse trapping experiments, and wind tunnel and Y-tube olfactometer studies in several countries demonstrating a behavioural response that results in increased trap capture of at least 12 thrips species, including the cosmopolitan virus vectors such as western flower thrips and onion thrips. Methyl isonicotinate has several of the characteristics that are required for an effective semiochemical tool and is being mainly used as a lure in combination with coloured sticky traps for enhanced monitoring of thrips in greenhouses. Research indicates that this non-pheromone semiochemical has the potential to be used for other thrips management strategies such as mass trapping, lure and kill, lure and infect, and as a behavioural synergist in conjunction with insecticides, in a range of indoor and outdoor crops.

Insecticidal activities of five pesticidal plant species, Tephrosia vogelii, Dysphania (Syn: Chenopodium) ambrosioides, Lippia javanica, Tithonia diversifolia and Vernonia amygdalina, which have been reported to control storage pests, were evaluated as leaf powders against Callosobruchus maculatus (Fabricius 1775) in stored cowpea. Their efficacy was compared with the commercial pesticide Actellic dust (pirimiphos-methyl) at the recommended concentration (50 g/90 kg), and with untreated cowpea seeds as a negative control. The plant powders were applied at concentrations of 0.01, 0.1, 1 and 3 g/10 g of cowpea seeds in 250 ml plastic containers (to measure contact toxicity), or 0.005, 0.05, 0.5 and 5 g tied in small muslin cloth bags and hung in 500 ml plastic bottles containing 10 g of cowpea seeds (to measure fumigant toxicity). Mortality of adults, oviposition deterrence, adult emergence, and percent seed damage were recorded. Complete protection of seeds and inhibition of adult emergence were achieved in Actellic dust-treated seeds; contact toxicity using leaf powders of T. vogelii at all concentrations, D. ambrosioides at concentrations of 0.1, 1 and 3 g and L. javanica at concentrations of 1 and 3 g; and fumigant toxicity using D. ambrosioides at concentrations of 0.5 and 5 g and L. javanica at a concentration of 5 g. Head space analysis of D. ambrosioides and L. javanica identified ascaridole and camphor, respectively, as components that could be responsible for the bioactivity of these plant species. These plants may, therefore, serve as effective but less harmful biopesticide alternatives to Actellic. Conversely, V. amygdalina and T. diversifolia were not effective, indicating that they should not be promoted for controlling bruchids in cowpea.

The larger grain borer Prostephanus truncatus Horn and the maize weevil Sitophilus zeamais Motschulsky are important pests of stored maize in the tropics, particularly where maize is stored on-farm with little control of moisture content and without use of pesticides. This study was undertaken to determine level of resistance among new experimental maize hybrids against P. truncatus and S. zeamais. Out of the 54 experimental hybrids tested, eight hybrids were resistant, six were susceptible and the remaining 40 hybrids were moderately resistant. Five hybrids showed considerable reduction in losses for both P. truncatus and S. zeamais (CKPH08013, CKPH08021, CKPH08003, CKPH08004 and CKPH08009), suggesting that they contained genes that confer resistance to the two pests. Low grain weight loss, powder production and low insect multiplication on resistant grains reduce the negative impact of the two beetle pests. Therefore, host plant resistance can be used as a vital component of an integrated pest management strategy against P. truncatus and S. zeamais.

This study was undertaken to provide new knowledge on biodiversity of aphids and their complex of natural enemies in vegetable agroecosystems in Benin. During a 2-year survey (2007/2008 to 2008/2009), aphid species, their host plants and natural enemies were identified from samples collected from 29 vegetable and 22 weed species at 30 vegetable production sites across Benin. A total of 82% of the vegetable species and 12% of the weed species were infested with aphids. Aphis gossypii Glover infested a wide range of the vegetables and occurred on 62% of the species, while Aphis craccivora Koch, Aphis spiraecola Patch, Lipaphis erysimi (Kalt.), Myzus persicae (Sulzer) and Toxoptera odinae (Van de Goot) were collected from a limited number of vegetables, each with a frequency occurrence ranging from 3 to 28%. The weeds Commelina benghalensis L. and Euphorbia hirta L. were common alternative weed hosts for aphids. Common natural enemies were the predators Cheilomenes propinqua (Mulsant), Cheilomenes sulphurea (Olivier) and Ischiodon aegyptius (Wiedemann), the obligate entomopathogen Neozygites sp., and the parasitoids Lysiphlebus testaceipes (Cresson) and Aphelinus ficusae Prinsloo & Neser. Lysiphlebus testaceipes was usually the only primary parasitoid on aphids across the sites and its common host was A. gossypii. From parasitized mummies, five species of hyperparasitoids were collected, the most abundant being Syrphophagus africanus (Gahan). These are the first records of L. testaceipes, S. africanus and A. spiraecola from West Africa. These findings provide baseline knowledge on the aphid fauna of Benin and contribute information for use in the development of sustainable vegetable pest management strategies in the country.

A study was carried out to develop a diet for mass rearing of the pink bollworm Pectinophora gossypiella (Saund.) and optimize bioassays for testing the bollworm's sensitivity to two insecticidal proteins from Bacillus thuringiensis (Bt). A P. gossypiella colony was established in the laboratory from field collections and its developmental biology was compared on various test diets. Larvae reared on a diet of cottonseed and chickpea flours for the first 10 days and subsequently on pieces of okra attained rapid growth and development. This two-phase diet has been used for successful laboratory rearing of 51 generations of the bollworm. Neonates were found to be sensitive to both the Bt proteins Cry1Ac and Cry2Ab2, which are produced by the transgenic Bt cotton products Bollgard™ and Bollgard II™.

Field trials in Kenya demonstrated that the forage grass, Sorghum vulgare sudanense (Sudan grass) attracted greater oviposition by stemborers than cultivated maize, resulting in significant increase in maize yield. On the other hand, the non-host forage plant, Melinis minutiflora (molasses grass), when inter-cropped with maize, repelled gravid stemborer females from ovipositing on maize, resulting in significant reduction in stemborer infestation. Using these trap- and repellent gramineous plants, a novel pest management approach based on a ‘push-pull’ or stimulo-deterrent diversionary strategy is being developed where stemborers are repelled from the food crop and are simultaneously attracted to a discard or trap crop. The plant composition and permanence of habitat surrounding maize fields also influence the abundance of natural enemies that invade agroecosy stems once a pest population is present. It may be advantageous to promote the growth of native Gramineae and other wild plants which minimise, or even suppress, population growth of pests during non-cropping seasons, but still provide a suitable habitat for natural enemies.

Published information was used to compile a summary of natural enemies (parasitoids, predators and diseases) reported attacking Spodoptera litura (F) under field conditions. Species (71) of insect parasitoids in seven families of Hymenoptera and two families of Diptera were listed as parasitoids of different stages of S. litura. Predatory insects (36) belonging to 14 families and 12 species of spiders from six families have been reported to feed on this species. Four protozoan, four fungal, seven bacterial, four each of viral and nematode species were also reported to be the pathogens of this species. Published information suggested that periodic releases of large number of egg parasites could help in suppressing populations of this pest. There is a considerable scope for increased attention to the role of natural enemies as component of integrated pest management programmes of S. litura.

The antestia bug Antestiopsis thunbergii (Gmelin 1790) is a major coffee pest in East Africa. Nymphs and adults feed on all vegetative and fruiting parts of the coffee tree leading to yield reduction and poor quality of coffee beans. Our study aimed to characterize the developmental biology and provide life table parameters for A. thunbergii reared in the laboratory. The biology of A. thunbergii was studied at four constant temperatures of 20, 25, 30 and 35°C with 80±5% RH and a photoperiod of L:D 12:12. Complete development of A. thunbergii from egg to adult occurred between 20 and 30°C, while eggs did not hatch at 35°C. Immature stage development time decreased significantly with an increase in temperature, with the exception of fifth nymphal stage, duration of which was similar for all temperatures. The fecundity was maximal at 20°C with an average of 132.8 eggs per female and 1.7 egg per female per day. The gross reproductive rate (GRR) was the highest at 20°C with 75.79 daughters per female compared to 19.56 and 2.69 daughters per female at 25 and 30°C, respectively. The intrinsic rate of increase r was maximal at 20°C with 0.013 and negative at 30°C. The time required for the reared population to double (doubling time Td ) was shorter at 20°C with 53.31 days compared to 115.52 days at 25°C. Our study provides basic information on A. thunbergii biology that will contribute to a better understanding of the pest distribution and dynamics on arabica coffee in East Africa.

Many pests, especially capsid bugs, infest cocoa and contribute to low yields in producing countries. In Ghana, synthetic pesticides are recommended for controlling the insect pests, and a combination of synthetic pesticides and cultural practices for diseases and weeds. However, the farmers in Ghana are not motivated to adopt these recommendations due to the high cost of pesticides and low producer prices. There is also concern that use of synthetic pesticides on a wide scale can affect both human health and the environment. With the objective of improving cocoa yields through environmentally friendly pest control practices, evaluation of an integrated pest management (IPM) package based on aqueous neem (Azadirachta indica A. Juss.) seed extracts to control the insect pests and cultural practices to manage the diseases, weeds and parasitic plants was undertaken in farmers' fields with their active participation. The IPM package improved yields significantly and was found to be more profitable than the farmers' practices. However, there are two major constraints to adoption of the package by farmers: it is labour-intensive and currently, neem is not readily available to the community. The study recommends that these constraints must be tackled to motivate the farmers to adopt or adapt the IPM package.

Mass trapping of red palm weevil Rhynchophorus ferrugineus (Olivier) using food-baited pheromone (ferrugineol) traps is a key component of the integrated pest management strategy adopted to combat this pest in date Phoenix dactylifera L. plantations of Saudi Arabia and other Middle Eastern countries. The present study aimed at ascertaining the density at which pheromone traps should be set in the field to mass trap adult R. ferrugineus. Our findings indicate that in plantations with low weevil activity and < 1% infested palms, a trap density of 1 trap/ha is sufficient. In plantations where infestation levels are >1%, 10 traps/ha recorded the best weevil captures. However, in area-wide mass trapping programmes, the pest could be effectively mass trapped at 4–7 traps/ha depending on the resources available.

The life cycle of the African wild silkmoth Gonometa postica Walker was studied between September 2000 and September 2001 in the Uasin Gishu District of western Kenya with Acacia mearnsii de Wild and Acacia hockii de Wild as host plants. The initial population of G. postica was set up from healthy live pupae in cocoons collected from host plants in the study area. Oviposition was carried out in net sleeves and small plastic cages. Moth emergence and oviposition were bimodal, occurring between September and October 2000 and between March and April 2001, respectively. Larvae were reared in semi-captivity by using net sleeves on the branches of the two host plants. Larvae passed through six developmental instars. The pupal stage lasted from December to February during the short rains and from June to September during the long rains. Moth fecundity in the net sleeves was higher than that of those kept in plastic cages and fewer eggs hatched in the plastic cages compared with the net sleeves. Larvae reared on A. mearnsii had a shorter developmental period compared with those reared on A. hockii. Male larvae spun cocoons earlier than females but moths of both sexes emerged simultaneously. Sexual dimorphism was exhibited in both pupal and adult stages, females being larger and heavier than males. The importance of the semi-captive rearing technique for sustainable utilization of wild silkmoths for mass production of cocoons is discussed.

The life cycles of two phycitid moths, Plodia interpunctella (Hubn.) and Ephestia cautella (Wik.) were studied under ambient laboratory conditions on groundnut, maize, sorghum, wheat and standard medium (maize/wheat/glycerol, 8:8:1, w/w). Egg hatchabilities were found to be 98.6 and 91.6% for P. interpunctella and E. cautella respectively. Five larval instars were recorded for each species based on head-capsule width measurements. The growth ratios of the larval head-capsule width ranged from 1.08–1.72 in P. interpunctella: and 1.33–1.57 in E. cautella. These ranges fall within the acceptable range in Dyar's rule. Mean fecundities ranged from 96.83 ± 0.31 on wheat to 190.87 ± 0.47 on standard medium for P. interpunctella; and 96.83 ± 0.31 on groundnut to 192 ± 1.33 on standard medium for E. cautella. Mean developmental periods of the two moths on the selected food media ranged from 25.65 days on standard medium to 46.11 days in broken wheat for P. interpunctella; and 26.95 days in broken sorghum to 40.14 days in ground maize for E. cautella.

Mass-rearing protocols must be developed, in particular, a cost-effective larval diet, to implement the sterile insect technique against Anastrepha fraterculus (Wiedemann). The key elements of this diet are the optimal nutrients and their concentrations, diet supports or bulking agents, and the pH of the diet. To improve the currently used formulation and develop a more cost-effective diet, in the present study, we evaluated various supports, sugar contents, nutrient proportions and pH levels. Egg-to-pupa recovery was found to increase when agar was replaced with sponge cloth in the diet. Although low, the recovery values obtained when using the sugarcane bagasse-based diet were similar to those obtained when using the agar-based diet, but the percentage of adult emergence was lower. Larval viability was found to increase when the amount of sugar in the diet was doubled. Yet, it is still necessary to evaluate this diet on a larger scale and determine the feasibility of reusing the sponge cloth to reduce the costs of larval diets.

The development, survival and reproductive potential of diamondback moth Plutella xylostella (Linnaeus) were studied at 25 ± 1 °C in the laboratory in response to two cultivated Brassica oleracea cultivars (cabbage B. oleracea var. capitata and kale B. oleracea var. acephala) and four wild crucifer species Erucastrum arabicum, Raphanus raphanistrum, Rorippa nudiuscula and Rorippa micrantha. Rorippa micrantha was the most preferred species in oviposition choice tests, while cabbage and kale were least preferred. First instar larval mining period differed significantly between plant species with the longest period recorded on cabbage (3.0 days) and the shortest on R. micrantha (0.4 days). Pupal weight was significantly lower for larvae reared on R. nudiuscula, while those of the others were similar. The developmental period from first instar to adult was the shortest on R. micrantha (14.1 days) and the longest on R. raphanistrum (15.6 days). Survival to adult was not statistically affected by the host plant species. Adult longevity ranged between 18.2 days on R. raphanistrum and 24.7 days on R. nudiuscula. The females were significantly heavier than the males on all plant species. However, males lived longer than females. Moths reared on R. nudiuscula recorded the highest fecundity (326 eggs), while moths reared on cabbage had the lowest fecundity (262 eggs). Kale and R. nudiuscula recorded the longest generation time of 31.7 days, while E. arabicum had the highest net reproductive rate (126.4 eggs per day). The highest intrinsic rate of increase was calculated for R. micrantha (0.179) and the lowest for kale (0.147). This study shows the suitability of wild crucifers as hosts for P. xylostella and indicates that they may play a major role as reservoir for the pest during the absence of cultivated host plants.

The papers presented in this special issue are focused on developing and validating procedures for artificial rearing of selected fruit fly species of economic importance for use in area-wide integrated pest programmes with a sterile insect technique (SIT) component. They are the result of a 5-year coordinated research project (CRP) on ‘Development and Improvement of Rearing Techniques for Anastrepha and Bactrocera Fruit Flies’ that was coordinated by the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture. Twenty-two CRP participants from 18 countries worked on both basic and advanced rearing procedures of different fruit fly species to overcome technical bottlenecks and to develop appropriate and relevant procedures for use in mass-rearing facilities. A variety of studies were undertaken for three groups of tephritid species: (1) those for which mass-rearing for SIT application was available, but further refinement would be useful; (2) those for which mass-rearing for SIT application was under development in the laboratory, but that had not reached mass-rearing status; and (3) those for which research to develop colonization and rearing methods was needed. Many of the protocols developed or improved during the CRP have been transferred to the different fruit fly mass-rearing facilities worldwide.

Coconut is one of the major crops of commercial importance among the palms. The leaf-eating caterpillar Opisina arenosella Walker is the most important lepidopteran pest of coconut palm in India and Sri Lanka. Assessment of crop loss is essential for a realistic planning for research and developmental policies. Information on the yield loss in coconut due to O. arenosella attack is very meagre. In the present study, results of investigations carried out on leaf-eating caterpillar-induced yield loss in coconut palms in Kerala, India, for a period of 4 years (2002–2005) are presented. A maximum crop loss of 45.4% in terms of nut yield was recorded from infested palms in the succeeding year of severe pest incidence. The infested palms also showed reduction in bunch and leaf production to the tune of 21.0 and 13.8%, respectively. The pest-attacked palms regained their normal yield potential by the fourth year after heavy pest infestation.

Chilo partellus Swinhoe (Lepidoptera: Pyralidae) is an exotic stemborer of cereal crops in Africa which invaded the continent from Asia earlier this century. In addition to Ch. partellus, several indigenous stemborers are found in Africa. In 1991, Cotesia flavipes Cameron (Hymenoptera: Braconidae), a gregarious endoparasitoid of stemborers in Asia, was introduced into Kenya for biological control of Ch. partellus. Laboratory studies revealed that the parasitoid could successfully parasitise not only the target stemborer, but also two native stemborers that occur sympatrically with Ch. partellus in some locations. Interbreeding studies demonstrated the Co. flavipes would mate with a native congener, Cotesia sesamiae (Cameron), but no female offspring resulted from these matings. Investigations on competition between the two Cotesia spp. indicated that when Ch. partellus was the host, Co. flavipes appeared to be a superior parasitoid. Releases of Co. flavipes were made in 1993 in Kenya. Recoveries in 1994,1995 and 1996 demonstrated that the parasitoid was firmly established in two regions of Kenya and in northern Tanzania. Preliminary observations suggest that the parasitoid is causing greater mortality to stemborers in southwestern Kenya than in the coastal area.

The aim of this study was to identify and develop entomopathogenic fungi as biopesticides for management of Maruca vitrata (Fabricius). Fourteen isolates of Metarhizium anisopliae (Metchnikoff) Sorokin and six of Beauveria bassiana (Bals.-Criv.) Vuill. were screened against first instar larvae of M. vitrata. The two most virulent isolates were selected and further tested for production in four liquid media. Different formulations of one isolate were evaluated against different developmental stages. Metarhizium anisopliae ICIPE 18 and ICIPE 69 caused highest larval mortality of 91 and 81%, with lethal time to 50% mortality (LT50) values of 1.8 and 1.7 days and LC50 of 1.07 × 107 and 3.01 × 106conidia/ml, respectively. ICIPE 69 yielded more biomass and propagules in two liquid media than ICIPE 18. All developmental stages and adult moths were susceptible to fungal infection and horizontal transmission caused a significant reduction in fecundity. Isolate ICIPE 69 was identified as the most potent isolate for managing M. vitrata based on demonstrated efficacy against different developmental stages and amenability to production in liquid media and could be utilized as an alternative to pesticides in cowpea IPM.

Maize (Zea mays L.) is Kenya's most important staple crop with annual production fluctuating between 2.6 and 3.1 million tons in 2012 and 2011, respectively. However, frequent food shortages are still experienced in the country. These have been attributed to pests and diseases and post-harvest constraints. The dominant post-harvest pest of maize is Sitophilus zeamais (Motsch.), which causes losses between 10 and 20% of harvested grain. The objective of this study was to establish the repellent activity of essential oils extracted from selected eucalyptus species against S. zeamais. Essential oils were extracted from the fresh leaves of Eucalyptus saligna Sm., Eucalyptus globulus Labill., Eucalyptus camaldulensis Schlecht and Eucalyptus citriodora Hook by steam distillation using a Clevenger-type apparatus. A repellency bioassay, with varying concentrations (0.002, 0.02, 0.2 and 2 μl/μl) of the oils, was carried out against the maize weevils using a Y-shaped olfactometer. Repeated measures of analysis of variance were applied to test the different doses and repellents, and their interactions against S. zeamais. The essential oils of E. camaldulensis and E. citriodora presented better repellent activity at the 2 μl/μl concentration (74.35 and 69.15%, respectively) followed by those of E. globulus (53.68%) and E. saligna (40.5%). Gas chromatography (GC)–mass spectrometry and GC co-injections with authentic samples showed the presence of the following major constituents in: (i) E. camaldulensis oil: 1,8-cineole (18.9%), α-cardinol (6.4%) and β-phellandrene (2.6%); (ii) E. citriodora oil: 1,8-cineole (11.2%), β-pinene (3.2%) and 4-terpineol (3.1%); and (iii) E. globulus oil: 1,8-cineol (17.2%), α-pinene (7.1%) and spathulenol (6.5%). The results provide a scientific rationale for the use of eucalyptus oils in the protection of maize against weevils.