The possibility that Sitophilus zeamais Motschulsky prefers a particular grain side and a grain side area for feeding, and the implications and value in maize programmes' breeding for resistance were investigated in the laboratory at ambient temperature (32.7 °C) and relative humidity (70.4%) using standard techniques. A total of 20 elite maize varieties were used: TZBRCOMP.2C1F1, TZBRELD3C5, PVASYN-3F2, PVASYN-6F2, DTSYN-11-W, BR9943DMRSR, IWDC3SNY-W, WHITEDTSTRSYN, 2008DTMA-YSTR and 2000SYNEE-WSTR, obtained from the Maize Breeding Unit of International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria, and ILE-1-OB, IFEMAIZEHYBRID-1, IFEMAIZEHYBRID-2, IFEMAIZEHYBRID-5, IFEMAIZEHYBRID-6, ARTCOMPOSITE-A-Y, ARTCOMPOSITE-B-Y, ART/98/SW1-OB, ART/98/SW4-OB and ART/98/SW5-OB, obtained from the Institute of Agricultural Research and Training (IAR&T), Moor Plantation, Ibadan, Nigeria. The flat side of a maize grain at the point of penetration was significantly preferred (P≤ 0.05), possibly because it provided much needed space for anchorage and feeding. The South locus of the flattened side of a maize grain was also significantly preferred (P≤ 0.05), possibly because of its soft nature and proximity to the nutrient-rich embryo. The findings of the study have implications for seed viability and can be considered in breeding for resistance to infestation by S. zeamais in stored maize.

In the Ecuadorian cloud forest, males of the parasitoid braconid wasp Napo townsendi Shaw displayed facultative lekking, appearing both singly and in groups of 2–7 on the leaf tops of various plant species. To attract females, they constantly employed a stereotypical, spread-winged calling behaviour, apparently releasing a sex pheromone combed from the lateral metasomal exocrine glands and applied to the wings and hind legs. Aggregated males used the same posture in conspecific agonistic displays, often leading to physical fighting. While female wasps were attracted to and mated with displaying singletons, they also made a choice among aggregated males. When females approached, males vibrated their wings in a brief courtship and mounted. Details of copulation behaviour, which lasted on an average of 3–4 min, are described. Without apparent physical weaponry, the displaying wasps successfully warded off attacks from an assortment of predatory arthropods, particularly salticid spiders. We present case studies of repeated unsuccessful predation attempts by salticids. Here, we postulate that calling and release of sex pheromone may double as both an intrasexual agonistic display and an aposematic advisory to predators that the wasps employ a chemical defence.

The present study investigated the incidence and effect of the Russian wheat aphid (RWA) Diuraphis noxia (Kurdjumov) on irrigated wheat yield at Debre Zeit, Ethiopia. Wheat varieties were sown at the rate of 140 kg/ha on Vertisols on plots of 3 × 3 m. Treatments were tested in a split plot with varieties as the subplot and insecticide as the main plot, and were replicated three times. RWA appeared first when the crop reached the four- to five-leaf stage (Zadoks stage 22). In 2012 season, the RWA population peaked in the last week of March, and at this peak infestation, the average number of RWA per tiller was 46.9 on Denbi, 59.6 on Kubsa, 63.6 on Millennium and 56.2 on Werer. However, there were less than three RWA per tiller on sprayed wheat. In 2013, at the peak population intensity, there were 10.1, 10.5, 9.6 and 10.2 RWA per tiller on Denbi, Kubsa, Millennium and Werer, respectively. However, on sprayed wheat, the average population was less than one per tiller. The pattern of population build-up observed in the 2014 season was similar to that in 2013. Natural enemies of RWA were only a few generalist predators and were found at an extremely low density. In the 2012 season, avoidable loss in plant height, seed weight, grain number and grain yield ranged from 3 to 10%, 32 to 47%, 12 to 25%, and 69 to 93%, respectively. In the 2013 season, avoidable loss in seed weight and grain yield varied between 14 and 20%, and 15 and 41%, respectively. Similarly, in the 2014 season, avoidable loss in seed weight ranged between 9 and 24% and in grain yield between 35 and 49%.

Along with plant sources, arthropods (such as millipedes) are also known for their antioxidant activities that can help combat human ailments. Therefore, methanolic extracts of males and females of two endemic giant pill-millipedes of the Western Ghats (Arthrosphaera fumosa Pocock and Arthrosphaera magna Attems) were evaluated for antioxidant potential. The bioactive principles and activities assessed were total phenolics, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl or DPPH radical scavenging, ferrous ion chelation, reducing power and hydrogen peroxidase scavenging. Significant differences were shown between the two species, the sexes and the sexes within millipede species in total antioxidant activity, DPPH radical scavenging and ferrous ion chelation. Total phenolics and EC50 of DPPH radical scavenging activity differed significantly only between species and the sexes. This study clearly demonstrated that the antioxidant capacity of the methanolic extract of Arthrosphaera spp. is comparable to the ascorbic acid standard and possesses potential scavenging ability against reactive oxygen species generated during oxidative stress.

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.

The species diversity of tephritid fruit flies in major mango-growing regions in Uganda was monitored over a 2-year period (2010–2012) using fruit bait and lure traps. A total of 368,332 specimens belonging to 10 species in four genera (Bactrocera, Ceratitis, Trirhithrum and Dacus) were collected. Of these, 98.9% belonged to Bactrocera invadens, while the second and third most common species were Dacus bivittatus (0.4%) and Ceratitis anonae (0.3%), respectively. Significant differences in the evenness and diversity of fruit fly species were noted across the regions. Fruit fly community structure was significantly different across the three regions. The Lake Victoria Crescent and Mbale Farmlands harboured significantly more D. ciliatus, T. coffeae, D. bivittatus and B. cucurbitae in contrast to the Northern Moist Farmlands and the Western Medium High Farmlands. Ceratitis rosa contributed the highest difference in regional structure, followed by C. fasciventris and C. cosyra. Rank abundance curves depicted a geometric series distribution of the species composition in the three regions, confirming a scenario of competitive displacement of native fruit fly species by B. invadens. A comprehensive and sustainable response strategy to B. invadens and other fruit flies needs to be urgently devised to protect the horticulture industry in Uganda.

This study was conducted on both station and farmers' fields during the 2010 dry cropping season in the Vallée du Kou rice scheme. We investigated the effect of three rice-transplanting periods (8–10 days) on the population dynamics, damage and parasitism associated with rice stem borers. The on-station experiment was designed as a randomized complete block with three treatments (planting dates) and four replications. Regular intervals of 14 days were observed between subsequent planting dates. Weekly agronomic and entomological assessments were performed from the 21st day after transplanting (DAT) to the 84th DAT. The on-farm experiment covered 1200 ha divided into two zones in which 48 farmers' fields were selected according to the periods of rice transplanting (resulting in 16 fields per period). On-station results indicated 10.1% of deadhearts and 7.5% of whiteheads due to stem borers in the first transplanting period, resulting in the lowest yield (2 metric tons/ha). In farmers' fields, the genus Chilo was found to be the most injurious rice stem borer in Vallée du Kou. The highest larval parasitism (38.5%) was recorded in the third treatment. These results provide important data that can be used in the development of an integrated management strategy for rice insect pests in Vallée du Kou.

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.

Stemborers are a major constraint to the production of rice in the Kou Valley, Burkina Faso. Biological control is a good alternative to the use of agrochemicals that are harmful to human and animal health, and the environment. A survey of natural enemies of stemborers was conducted during the 2014 rice-cropping season across three transplanting periods (P1, P2 and P3). Plant and insect samples were collected by mowing and trapping at weekly intervals until harvest, starting 21 days after transplanting, and examined microscopically. Immature stages of the parasitized stemborers were reared to maturity for a positive identification of the parasitoids. Three genera of stemborers were identified: Chilo (Lepidoptera: Pyralidae), Maliarpha (Lepidoptera: Pyralidae) and Sesamia (Lepidoptera: Noctuidae). The Chilo genus was the most important with an average percentage of 41.4% of the pre-imaginal population in P2 followed by Marliarpha (1.1%) and Sesamia (0%). A total of 15 hymenopteran parasitoid species that included nine genera and seven families were identified. All the parasitoids were associated with Chilo and only two of the species parasitized Maliarpha. The most frequent parasitoids encountered were Bracon testacerofatus, Goniozus indicus, Dolichogenidea oryzae and Bracon spp. A total of 28 predator species were recorded from 22 genera, 6 orders and 15 families. Leucauge sp., Agriocnemis sp., Lycosa pseudoannulata and Lycosa sp. were the most important predators with frequencies reaching 15% of the arthropods caught in some fields. These results will be employed to develop a sustainable system to manage rice stemborers.

Trans-generational transfer of gregarious-phase traits in the desert locust Schistocerca gregaria (Forskål, 1775) is mediated by primer gregarizing pheromonal signals produced by ovipositing females that experience crowding. We monitored time-course proteomic events in eggs from solitary-reared locusts that had been exposed for 1, 3, 5, 7, 10 and 12 days to different levels of the sand-associated gregarizing signal originating from 0, 3, 5 or 10 ovipositions by crowd-reared females. Evidence for the phase transition was sought by comparing the protein patterns of embryos thus exposed with those from crowd-reared (gregarious) controls; this comparison was continued until the stage of the first instars. Expressed proteins were analysed by two-dimensional protein gel electrophoresis, and patterns from the different treatments within stages were compared by profile matching and χ2 analyses. Eggs derived from crowd- and solitary-reared females showed essentially similar protein patterns at early stages of embryogenesis; however, mature stages (particularly, days 10 and 12) and hatchlings demonstrated significantly different patterns. Protein patterns of eggs from solitary-reared females that were incubated in sand contaminated with the pheromonal signal and of the hatchlings that emerged were similar to those derived from gregarious females and dependent on the level of the pheromone to which the embryos had been exposed. The results confirm the gregarizing effect of the signal and constitute a useful basis for unravelling the mechanism of the signalling cascades associated with gene expressions triggered by the pheromone.

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 effects of sowing date, host plant and insecticidal control of the stemborer Busseola fusca Fuller were studied in the highlands of Eritrea at Halhal Begos in 2003–2005. Sowing date had a significant effect on stemborer incidence and damage levels. Early sowing dates (April 1 and 15) had significantly lower numbers of larvae, percent infestation and deadhearts, and produced higher yields compared with later sowing dates. In the host preference experiment, Sudangrass (Sorghum× drummondii (Steud.) Millsp. & Chase) had the highest infestation (91%), and it was the most preferred host for oviposition among the tested plants. All the chemical treatments significantly reduced stemborer infestation and damage levels compared with untreated plots. Furadan and Cymbush significantly lowered infestation and larval damage. There were significant differences in days to heading, maturity, plant height and yield. In general, the study showed that early planting coupled with host preference and insecticides reduced the infestation of stemborers and significantly increased the yield of sorghum in the highlands of Eritrea.

The efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant (AWA) Oecophylla longinoda Latreille was evaluated at orchards in Bagamoyo and Mkuranga districts, Coast region of Tanzania, during the cashew off-seasons in 2011 and 2012. The baits were applied at monthly intervals; the dynamics of AWA were monitored by counting the number of leaf nests/tree and the colonization trails on main branches. The numbers of leaf nests recorded before baiting ranged between 3.5 and 5.3 and were not significantly different at both sites and in both seasons; after baiting, they ranged between 3.2 and 11.6 at Bagamoyo and between 3.0 and 10.2 at Mkuranga. The colonization of AWA trails recorded before baiting was also not significantly different at both sites and in both seasons and ranged between 37.9 and 50.0%; after baiting, this ranged between 35.9 and 75.1% at Bagamoyo and between 34.6 and 79.2% at Mkuranga. The provision of fish- and hydramethylnon-based baits can effectively contribute to the conservation of AWA during the cashew off-seasons. The fish-based bait is cheaper and more easily affordable by local farmers and can, therefore, be used as an alternative diet for AWA at this time.

Bemisia tabaci (Gennadius) is a global insect pest that transmits many important plant viruses. A field study was conducted on infestation by B. tabaci and incidence of whitefly-transmitted viruses after the application of selected foliar and seed-treated biorational insecticides in seven vegetable and row crops in Egypt. Three foliar insecticides (Actara, Biofly and Neemix) and a treated check (Actellic) were assayed across three weeks on seedlings and mature plants, and two seed-treated insecticides (Actara and Gaucho) and a treated check (Aldicarb) were assayed on seedlings. All of the foliar insecticides led to 60–100% reductions in whitefly infestations in each crop. Biofly and Neemix were the least efficacious insecticides. Incidences of whitefly-transmitted viruses were reduced in each insecticide-treated plot with seedlings of four crops; however, no effect on virus incidence was observed in the experiment with mature plants. Crops of cucumber, eggplant, squash and tomato displayed symptoms characteristic of Cucumber vein yellowing virus, Squash leaf curl virus or Tomato yellow leaf curl virus; however, no symptoms of whitefly-transmitted viruses were observed in green bean, potato or sugar beet. The results show that several biorational insecticides may suppress whitefly populations in seedlings to delay whitefly-transmitted viruses in some vegetable crops in Egypt.

An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit flies in the northern savannah ecology of Ghana. Fruit samples from 80 potential host plants (wild and cultivated) were collected and incubated for fly emergence; 65 (81.5%) of the plant species were positive to fruit flies. From records in Africa, 11 plant species were reported to be new hosts to the African invader fly, Bactrocera invadens (Drew, Tsuruta and White, 2005). This study documented the first records of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation by B. invadens was higher in the cultivated fruits; Ceratitis cosyra dominated in most wild fruits. Cucurbitaceae were mainly infested by three species of Dacus and Bactroceracucurbitae, a specialized cucurbit feeder. Among the commercial fruit species, the highest infestations were observed in mango, tomato, sweet pepper and watermelon, whereas marula plum, soursop, tropical almond, sycamore fig, African peach, shea nut, persimmon, icacina and albarillo dominated the wild host flora. The widespread availability of host plants and the incidence of diverse fly species in the ecology call for particular attention to their impact on commercial fruits and the development of sustainable management strategies against these economically important pests in Ghana.

Glutathione S-transferases (GSTs) have been recognized as important metabolic detoxifying enzymes in many phytophagous insects. However, the contribution of GST to insecticide resistance in Zonocerus variegatus (L.) has not been studied. Therefore, we carried out an initial study on the induction and kinetics of GST in Z. variegatus exposed to pyrethroids (PYRs) and Ocimum gratissimum leaf extract. Fifth-instar nymphs of Z. variegatus collected from cassava farms (with no history of insecticide exposure) on the campus of the University of Ibadan were reared to adult stage. Adult insects were divided into four groups of two replicates, each consisting of 30 insects. The groups were exposed to 20 ml of PYR insecticide and 25 mg/dl and 250 mg/dl of O. gratissimum leaf extract, respectively, while the last group served as the control. GST was extracted from the body tissues of the insects using the Bradford method and the kinetics of the enzyme was evaluated using the Lineweaver–Burk plots. No mortality was recorded in insects exposed to 25 mg/dl of O. gratissimum leaf extract, while mortality rates of 93.3 and 43.3% were recorded in insects exposed to PYR insecticide and 250 mg/dl of O. gratissimum leaf extract, respectively. The activity of GST was higher in insects exposed to the insecticides than in the control insects, while a higher enzyme activity was recorded in insects that died after exposure to the insecticides than in insects that were alive after exposure. The GST extracted from insects that were alive after exposure to PYR insecticide and O. gratissimum leaf extract exhibited a high affinity for the glutathione substrate compared with that extracted from insects that died after exposure. Higher GST activity in insects exposed to insecticides is indicative of the role of this enzyme in the metabolic detoxification of insecticides by Z. variegatus.

This study used the theory-based impact evaluation approach to understand as to how promotion of beekeeping by the Commercial Insects Programme (CIP) of the International Centre of Insect Physiology and Ecology (icipe) has had an impact on honey production in the former Mwingi District of Kenya (now merged into Kitui County). We examined the adoption of modern hives promoted by icipe and applied data envelopment analysis (DEA) to assess the technical efficiency (TE) of participants in CIP. CIP participants had an average TE of 0.56, which was significantly higher than that of non-participants in the former Kitui District (average TE of 0.26). Those who adopted modern hives achieved the highest average levels of TE (0.59). The study fits a Probit model to identify the drivers of adoption and a Tobit model to assess the intensity of adoption of modern hives. The propensity score matching approach was used to evaluate the impact of modern hives on honey production. Results indicate that perceptions about the yield and quality of honey obtained from modern hives significantly increased beekeepers' adoption decisions. The intensity of adoption expressed as the proportion of modern hives owned by beekeepers was significantly high among farmers who participated in CIP. A positive and significant relationship was observed between the adoption of modern hives and the quantity of honey produced. The present study indicates, through the average TE, that considerable room still exists for the improvement of beekeeping and provides strong evidence for scaling up the dissemination of modern hives in areas of Kenya with high potential.

Susceptibility studies keep farmers informed, and enhance breeding programmes' testing against infestation and damage by stored product pests. Therefore, the susceptibility of 20 elite maize varieties to Sitophilus zeamais infestation was investigated in the laboratory at 32.7 °C ambient temperature and 70.4% relative humidity. The varieties tested were obtained from the Maize Breeding Units of International Institute of Tropical Agriculture (IITA), and Institute of Agricultural Research and Training (IAR&T), both in Ibadan, Nigeria. Susceptibility was assessed, using as indices, weevil mortality and survival rates, percentage grain damage, percentage grain weight loss, weight of grain powder, weevil development time, and number of emerged adults. The susceptibility index was determined post-infestation at 56 days using Dobie's formula and at 90 days from a new formula derived from Dobie's formula. Susceptible varieties produced significantly (P≤ 0.05) high numbers of F1 and F2 progeny, and had significantly (P≤ 0.05) low weevil mortality and early first weevil emergence. Grain damage and loss increased with storage duration. There was no visible damage to varieties 2000SYNEE-WSTR and TZBRELD3C5 at 56 days post-infestation. At 90 days, the two varieties had the lowest percentage grain damage, percentage weight loss, and weight of grain powder. The index of susceptibility at F2 progeny showed that the resistant varieties decreased in number from 17 (85%) to 13 (65%) and the moderately resistant varieties increased from 2 (10%) to 6 (30%). This suggests the effect of prolonged storage duration on the inherent ability of varieties to resist weevil attack. Variety PVASYN3F2 was susceptible. The factors conferring high resistance to 2000SYNEE-WSTR and TZBRELD3C5 should be investigated. They should be promoted to control S. zeamais infestation and damage in stored maize.