Development of reference transcriptomes for the major field insect pests of cowpea: a toolbox for insect pest management approaches in West Africa

Cowpea is a widely cultivated and major nutritional source of protein for many people that live in West Africa. Annual yields and longevity of grain storage is greatly reduced by feeding damage caused by a complex of insect pests that include the pod sucking bugs, Anoplocnemis curvipes Fabricius (Hemiptera: Coreidae) and Clavigralla tomentosicollis Stål (Hemiptera: Coreidae); as well as phloem-feeding cowpea aphids, Aphis craccivora Koch (Hemiptera: Aphididae) and flower thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae). Efforts to control these pests remain a challenge and there is a need to understand the structure and movement of these pest populations in order to facilitate the development of integrated pest management strategies (IPM). Molecular tools have the potential to help facilitate a better understanding of pest populations. Towards this goal, we used 454 pyrosequencing technology to generate 319,126, 176,262, 320,722 and 227,882 raw reads from A. curvipes, A. craccivora, C. tomentosicollis and M. sjostedti, respectively. The reads were de novo assembled into 11,687, 7,647,10,652 and 7,348 transcripts for A. curvipes, A. craccivora, C. tomentosicollis and M. sjostedti, respectively.Functional annotation of the resulting transcripts identified genes putatively involved in insecticide resistance, pathogen defense and immunity. Additionally, sequences that matched the primary aphid endosymbiont, Buchneraaphidicola, were identified among A. craccivora transcripts. Furthermore, 742, 97, 607 and 180 single nucleotide polymorphisms (SNPs) were respectively predicted among A. curvipes, A. craccivora, C. tomentosicollis and M.sjostedti transcripts, and will likely be valuable tools for future molecular genetic marker development. These results demonstrate that Roche 454-based transcriptome sequencing could be useful for the development of genomic resources for cowpea pest insects in West Africa

The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa

The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of FST=0.1 (ENA corrected FST=0.1) was significant (P≤0.05) and corroborated by pairwise FST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata

Genetic Differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) Populations on Cultivated Cowpea and Wild Host Plants: Implications for Insect Resistance Management and Biological Control Strategies

Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a polyphagous insect pest that feeds on a variety of leguminous plantsin the tropics and subtropics. The contribution of host-associated genetic variation on population structure wasinvestigated using analysis of mitochondrial cytochrome oxidase 1 (cox1) sequence and microsatellite marker data from M.vitrata collected from cultivated cowpea (Vigna unguiculata L. Walp.), and alternative host plants Pueraria phaseoloides(Roxb.) Benth. var. javanica (Benth.) Baker, Loncocarpus sericeus (Poir), and Tephrosia candida (Roxb.). Analyses ofmicrosatellite data revealed a significant global FST estimate of 0.05 (P#0.001). The program STRUCTURE estimated 2genotypic clusters (co-ancestries) on the four host plants across 3 geographic locations, but little geographic variation waspredicted among genotypes from different geographic locations using analysis of molecular variance (AMOVA; amonggroup variation 20.68%) or F-statistics (FSTLoc =20.01; P = 0.62). These results were corroborated by mitochondrialhaplotype data (QSTLoc = 0.05; P = 0.92). In contrast, genotypes obtained from different host plants showed low butsignificant levels of genetic variation (FSTHost = 0.04; P = 0.01), which accounted for 4.08% of the total genetic variation, butwas not congruent with mitochondrial haplotype analyses (QSTHost = 0.06; P = 0.27). Variation among host plants at a locationand host plants among locations showed no consistent evidence for M. vitrata population subdivision. These resultssuggest that host plants do not significantly influence the genetic structure of M. vitrata, and this has implications forbiocontrol agent releases as well as insecticide resistance management (IRM) for M. vitrata in West Africa.C

The prospect of animated videos in agriculture and health: a case study in Benin

Cell-phone ready educational videos, translated into local languages, are a recent phenomenon in developing nations. One of the reasons for the emergence of this approach is due to the scarcity of other forms of educational materials with appropriate content for low literate learners. Additionally, the World Wide Web (WWW) has very little to offer in regards to audio-visual training materials that could be used to educate people in their own local languages without the need for literacy. Scientific Animations Without Borders (SAWBO) creates and works with local groups to deploy educational videos in local languages facilitating access to information and knowledge toindividuals in the developing world. This paper is based on a survey conducted with 83 individuals on the perception of three SAWBO educational animations - neem extracts for insect control, cholera and malaria prevention; and their potential as training tools for health and agricultural extension in Benin. These animations provide information and knowledge in a simple way, on complex ideas and techniques that could improve livelihoods. The results obtained in this studysuggest that animated videos are a well-received approach as a training tool in agriculture andprevention of diseases amongst populations with diverse literacy levels

Resistance status of upland NERICA rice varieties to termite damage in northcentral Nigeria

Upland rice is mostly at risk from soil insect pests, including termites which cause significant yield losses. Studies were conducted at Kasua-Mangani, Kaduna State, Northcentral Nigeria, to evaluate the resistance status of 18 upland NERICA rice varieties to termite attack. The percent plant attacked by termites on the 18 NERICA varieties at 60 and 90 Days after Sowing (DAS) was between 2.47 to 12.45% and 3.82 to 20.89%, respectively. There was no significant difference in the response of NERICA rice varieties to termite attack at 60 and 90 DAS. The resistance status of NERICA rice varieties to termite attack was classified into 4 groups as follows: Moderately Resistant (MR), Moderately Susceptible with recessive resistance (MSr), Moderately Susceptible (MS) and Highly Susceptible (HS) according to cluster analysis. Of the 18 NERICA rice varieties studied, only NERICA 5, 14 and 18 were classified as MR and could be recommended as the most adapted rice varieties in termite prone areas of Northcentral Nigeria

Efficacy of traditional practices and botanicals for the control of termites on rice at Ikene, southwest Nigeria

Upland rice is mostly at risk from soil-borne insect pests, including termites, which cause significant crop yield losses. Studies were conducted in 2005 and 2006 at Ikenne, southwest Nigeria to assess the effectiveness of two traditional practices (cow dung and red palm oil mixed with pawpaw), two plant extracts (neem seed oil and neem powder) and Furadan coated with garri (cassava flour) against termite attacks on nine rice varieties—NERICAs 1–7, LAC 23 and OS 6. In 2005, the results showed that neem seed oil was more effective than neem powder and cow dung in the control of termites. Of the five treatments in 2006 (Furadan coated with garri, neem seed oil, neem powder, cow dung and red palm oil mixed with pawpaw), two treatments—neem seed oil and Furadan coated with garri—gave the best protection against termite attack. Among the rice varieties, termite attack was significantly lower on NERICA 5 than on the other NERICA varieties in both years. NERICA 5 was apparently the least attacked by termites when unprotected, indicating that it could be used as a resistant check variety for termites. Yield losses were lower in the treated than in the control plots. These findings indicate that botanicals, such as neem seed oil, can provide effective control against termites on rice fields and can also be used as alternatives to persistent chemical pesticides. This study has far-reaching implications because neem seed oil is environmentally safe, easy to prepare, readily available and affordable by resource-poor farmers in Nigeria

The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa

The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of FST=0.1 (ENA corrected FST=0.1) was significant (P≤0.05) and corroborated by pairwise FST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatialgenetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata