scholarly journals Efficacy of a cry1Ab Gene for Control of Maruca vitrata (Lepidoptera: Crambidae) in Cowpea (Fabales: Fabaceae)

2020 ◽  
Vol 113 (2) ◽  
pp. 974-979
Author(s):  
Prince C Addae ◽  
Mohammad F Ishiyaku ◽  
Jean-Batiste Tignegre ◽  
Malick N Ba ◽  
Joseph B Bationo ◽  
...  
Keyword(s):  
Insect Pests ◽  
Field Trials ◽  
Genetically Engineered ◽  
Maruca Vitrata ◽  
Sub Saharan Africa ◽  
High Dose ◽  
Cry1ab Protein ◽  
Cry1ab Gene ◽  
Pod Borer ◽  
Sub Saharan

Abstract Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20–80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists. The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.

scholarly journals Distribution and diversity of alternate hosts of Maruca vitrata Fabricius in three West African countries

2021 ◽  
Author(s):  
Prince Christopher Addae ◽  
Y. Anani Bruce ◽  
Iliyasu M. Utono ◽  
Mumuni Abudulai ◽  
Fousseni Traore ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Insect Pests ◽  
West African ◽  
Maruca Vitrata ◽  
Northern Ghana ◽  
High Dose ◽  
Alternate Host ◽  
African Countries ◽  
Alternate Hosts ◽  
Pod Borer

AbstractThe evolution of resistance to the Bacillus thuringiensis (Bt) toxins by insect pests is a major threat to Bt technology. However, the rate of resistance can be slowed with appropriate integrated insect resistance management (IRM) strategies. Surveys were conducted to identify alternate host species for Maruca vitrata (commonly called the legume pod borer or Maruca) that could serve as refuges for Pod-Borer Resistant (PBR) cowpea in three West African countries (Ghana, Nigeria, and Burkina Faso). Survey sites included 25 in northern Ghana, 44 in northern Nigeria, and 52 in north-central and southwestern Burkina Faso. Alternate hosts of Maruca identified from plant species belonging to the Fabaceae family that showed signs of Maruca damage on cowpea tissues were collected and dissected. Larvae that were found during these dissections were reared to adult moths in the laboratory then identified to species. The alternate host plants including species of Crotolaria, Sesbania, Tephrosia, and Vigna were the most frequently encountered among sites and locations. Flowering and podding of these plants overlapped with flowering and podding of the nearby (~200 m) cowpea crop. Abundance of these wild hosts and overlapping flowering patterns with the cowpea crop in most locations have the potential to sustain ample numbers of Bt susceptible Maruca that will mate with possible resistant Maruca and deter resistance development. Further quantitative studies, however, are required from each location to determine if actual Maruca production from alternate hosts is sufficient for a PBR IRM strategy. If verified, this approach would be compatible with the high dose/refuge IRM strategy that includes alternate hosts and non-Bt crops as refuges.

scholarly journals Phylogeographical Structure in Mitochondrial DNA of Legume Pod Borer (Maruca vitrata) Population in Tropical Asia and Sub-Saharan Africa

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0124057 ◽  
Author(s):  
Malini Periasamy ◽  
Roland Schafleitner ◽  
Krishnan Muthukalingan ◽  
Srinivasan Ramasamy
Keyword(s):  
Mitochondrial Dna ◽  
Maruca Vitrata ◽  
Sub Saharan Africa ◽  
Tropical Asia ◽  
Pod Borer ◽  
Legume Pod Borer ◽  
Sub Saharan

scholarly journals Transcontinental dispersal of Anopheles gambiae occurred from West African origin via serial founder events

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Hanno Schmidt ◽  
Yoosook Lee ◽  
Travis C. Collier ◽  
Mark J. Hanemaaijer ◽  
Oscar D. Kirstein ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
East Africa ◽  
Field Trials ◽  
Genetic Distances ◽  
Oceanic Islands ◽  
Genetically Engineered ◽  
Sub Saharan Africa ◽  
Anopheles Gambiae S.S ◽  
Sub Saharan ◽  
Founder Events

AbstractThe mosquito Anopheles gambiae s.s. is distributed across most of sub-Saharan Africa and is of major scientific and public health interest for being an African malaria vector. Here we present population genomic analyses of 111 specimens sampled from west to east Africa, including the first whole genome sequences from oceanic islands, the Comoros. Genetic distances between populations of A. gambiae are discordant with geographic distances but are consistent with a stepwise migration scenario in which the species increases its range from west to east Africa through consecutive founder events over the last ~200,000 years. Geological barriers like the Congo River basin and the East African rift seem to play an important role in shaping this process. Moreover, we find a high degree of genetic isolation of populations on the Comoros, confirming the potential of these islands as candidate sites for potential field trials of genetically engineered mosquitoes for malaria control.

scholarly journals Etude de l’effet rémanent de Mavi MNPV dans un champ de niébé

2020 ◽  
Vol 14 (6) ◽  
pp. 2219-2229
Author(s):  
A. Kindozandji ◽  
B.D. Datinon ◽  
K. Amevoin ◽  
A.N. Nondichao ◽  
A.I. Glitho ◽  
...  
Keyword(s):  
Research Work ◽  
Residual Effect ◽  
Maruca Vitrata ◽  
Sub Saharan Africa ◽  
Important Food ◽  
Food Legumes ◽  
Significant Difference ◽  
Sub Saharan ◽  
Rate Of Emergence ◽  
And Control

Le niébé est l’une des légumineuses alimentaires la plus importante dans toutes les régions de l’Afrique Sub-saharienne. L’objectif de ce travail était d’étudier l’effet rémanent de Mavi Multinucléo polyhedrovirus (Mavi MNPV) après la récolte du niébé au champ. Le champ a été traité 5 fois au biopesticide Mavi MNPV à la fréquence de sept jours. Deux semaines après la récolte, deux plants ainsi que les graines de chaque traitement sur chaque unité parcellaire ayant reçu les traitements de Mavi MNPV de 107, 108 et 109 virions/ml ont été collectés et amenés au laboratoire avec le substrat de développement de la plante (sable). Aucune des formulations issues des substrats sable, racines, feuilles, tiges et graines n’a affecté la mortalité des larves L2 et L3 de Maruca vitrata et aucune différence significative n’a été observée entre les traitements et le témoin. Quels que soient les traitements, le taux d’émergence des adultes est élevé ; ce qui signifie que la variation de la concentration de Mavi MNPV ne conditionne pas sa présence dans le sol, les tiges, les feuilles, les racines et les graines. Le biopesticide Mavi MNPV n’est pas persistant dans la nature.Mots clés : Niébé, Mavi MNPV, Maruca vitrata, Effet rémanent   English Title: Study of the residual effect of Mavi MNPV in a cowpea field Cowpea is one of the most important food legumes in all regions of Sub-Saharan Africa. The objective of this research work was to study the persistence effect of Mavi Multinucleus polyhedrovirus (Mavi MNPV) after field harvest of the cowpea. The field was treated 5 times with Mavi MNPV biopesticide at seven days. Two weeks after harvest, two plants as well as the seeds from each treatment on each plot unit that received Mavi MNPV treatments of 107, 108 and 109 virions / ml were removed and brought to the laboratory with the plant development substrate (sand). None of the formulations from sand, root, leaf, stem and seed substrates did not affect the mortality of L2 and L3 larvae of Maruca vitrata and no significant difference was observed between treatments and control. Regardless of the treatments, the rate of emergence of adults is high; this means that the variation in the concentration of Mavi MNPV does not condition its presence in soil, stems, leaves, roots and seeds. Mavi MNPV biopesticide is not persistent in nature.Keywords: Cowpea, Mavi MNPV, Maruca vitrata, Residual effect.      

Tracing the distribution of natural enemies of non-native invasive eucalypt insect pests in sub-Saharan Africa

2021 ◽  
pp. 1-10
Author(s):  
Mesfin Wondafrash ◽  
Bernard Slippers ◽  
Birhane A Asfaw ◽  
Idea A Makowe ◽  
Herbert Jenya ◽  
...  
Keyword(s):  
Natural Enemies ◽  
Insect Pests ◽  
Sub Saharan Africa ◽  
Sub Saharan ◽  
Native Invasive

scholarly journals PO 8719 INTRODUCING A NEW AFRICA MENINGITIS NETWORK – A NORTH-SOUTH COLLABORATION

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A63.1-A63
Author(s):  
Mosepele Mosepele ◽  
Cecilia Kanyama ◽  
David Meya ◽  
Fiona Cresswell ◽  
Timothee Chammard ◽  
...  
Keyword(s):  
Treatment Strategies ◽  
Sub Saharan Africa ◽  
High Dose ◽  
Diagnostic Strategies ◽  
Cns Infections ◽  
Study Protocols ◽  
Sub Saharan ◽  
Novel Treatment Strategies ◽  
Set Up ◽  
Randomised Controlled

BackgroundCentral nervous system infections, including meningitis, continue to cause significant morbidity in Africa. HIV has contributed to the epidemiology of CNS infections in this setting. Notable advances in the study of CNS infections by several groups have demonstrated the utility of new diagnostic strategies and impact of novel treatment strategies. However, efforts to coordinate meningitis research in Africa, and between Africa and the rest of the world remain very limited.MethodsIn a bid to promote a coordinated study of CNS infections across Africa, and in collaboration with other meningitis groups globally, the researchers of the AMBITION study (High Dose Ambisome on a Fluconazole Backbone for Cryptococcal Meningitis Induction Therapy in Sub-saharan Africa: A Randomised Controlled Non-inferiority Trial) are leveraging the EDCTP support for the AMBITION trial to set up an Africa Meningitis Trials Network.ResultsThe Africa Meningitis Trials Network (AMNET) was launched in Malawi in early 2018. Main achievements since the launch of the network, include an internal review of meningitis research across network sites and launch of the network website. The network also has two study protocols pending ethics review at all sites. These studies will provide much needed information on resources available for meningitis care, research and provide a baseline epidemiology of meningitis in Africa.ConclusionAMNET provides a rare opportunity for investigators interested in meningitis research to leverage the ongoing AMBITION trial to conduct Africa-wide preliminary research on meningitis. The network is recruiting additional members in Africa and globally to collaborate on meningitis research, and also apply for research funding to support meningitis work. Anyone interested in knowing more about the network should contact the AMNET communications officer, Ms Phum’lani Machao, [email protected]

scholarly journals Amenability of Maruca vitrata (Lepidoptera: Crambidae) to gene silencing through exogenous administration and host-delivered dsRNA in pigeonpea (Cajanus cajan L.)

2021 ◽  
Author(s):  
Madhurima Chatterjee ◽  
Jyoti Yadav ◽  
Maniraj Rathinam ◽  
Kesiraju Karthik ◽  
Gopal Chowdhary ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Target Genes ◽  
Insect Pests ◽  
Crop Improvement ◽  
Maruca Vitrata ◽  
Economic Losses ◽  
In Planta ◽  
Biotic Stresses ◽  
Pod Borer ◽  
Plant Level

Abstract Insect pests are one of the major biotic stresses limiting yield in commercially important food crops. The lepidopteran polyphagous spotted pod borer, Maruca vitrata causes significant economic losses in legumes including pigeonpea. RNAi-based gene silencing has emerged as one of the potential biotechnological tools for crop improvement. We report in this paper, RNAi in M. vitrata through exogenous administration of dsRNA encoding three functionally important genes, Alpha-amylase (α-amylase), Chymotrypsin-like serine protease (CTLP) and Tropomyosin (TPM) into the larval haemolymph and their host-delivered RNAi in pigeonpea. Significant decline in the expression of selected genes supported by over-expression of DICER and generation of siRNA indicated the occurrence of RNAi in the dsRNA-injected larvae. Additionally, the onset of RNAi in the herbivore was demonstrated in pigeonpea, one of the prominent hosts, by host-delivered RNAi. Transgenics in pigeonpea (cv. Pusa992), a highly recalcitrant crop, were developed through a shoot apical meristem-targeted in planta transformation strategy and evaluated. Plant level bioassays in transgenic events characterized and selected at molecular level showed mortality of M. vitrata larvae as well as reduced feeding when compared to wild type. Furthermore, molecular evidences for down regulation of target genes in the insects that fed on transgenics authenticated RNAi. Considering the variability of gene silencing in lepidopteran pests, this study provided corroborative proof for the possibility of gene silencing in M. vitrata through both the strategies.

scholarly journals ​Screening of Black Gram Genotypes against Major Pod Borers

2021 ◽  
Author(s):  
Abhishek Yadav ◽  
Gaje Singh ◽  
Amit Yadav ◽  
Hem Singh ◽  
Veer Singh ◽  
...  
Keyword(s):  
Insect Pests ◽  
Storage Condition ◽  
Maruca Vitrata ◽  
Black Gram ◽  
Resistant Cultivars ◽  
Kharif Season ◽  
Pulse Crop ◽  
Unique Position ◽  
Indian Agriculture ◽  
Pod Borer

Background: Blackgram (Vigna mungo L.) is an important pulse crop occupying a unique position in Indian agriculture and it stands fourth in area and production among the pulses. The popularity of this pulse is due to its nutritional and industrial values. Blackgram crop is attacked by a number of insect pests from sowing to harvest in the field as well as in storage condition. Among these insects-pests pod borers i.e. spotted pod borer, Maruca vitrata (Geyer) and gram pod borer, Helicoverpa armigera (Hubner) are serious insect-pests of black gram causing seed and pod damage. Therefore, keeping these views in mind, the present study was conducted. Methods: Present investigations were carried out during Kharif season of 2018 and 2019 to identify the resistant cultivars that are less susceptible to spotted pod borer and gram pod borer in black gram. Result: Fifteen black gram genotypes were screened against pod borers i.e. M. vitrata and H. armigera. When the data of both years were pooled, the two genotypes viz., KU-99-05 and Azad Urd-1 were found with minimum pod infestation of 7.67 and 9.67 per cent, respectively and categorized as resistant (R) against M. vitrata. The four genotypes KU-99-05, Azad Urd-1, Shekhar-2 and PU-6 were classified as resistant (R) against H. armigera with minimum pod infestation of 5.83, 6.17, 8.50 and 9.83 per cent, respectively during both the consecutive seasons (Kharif, 2018 and 2019).

scholarly journals Genomic Prediction of Tropical Maize Resistance to Fall Armyworm and Weevils: Genomic Selection Should Focus on Effective Training Set Determination

2020 ◽  
Author(s):  
Arfang Badji ◽  
Lewis Machida ◽  
Daniel Bomet Kwemoi ◽  
Frank Kumi ◽  
Dennis Okii ◽  
...  
Keyword(s):  
Genomic Selection ◽  
Genomic Prediction ◽  
Insect Pests ◽  
Fall Armyworm ◽  
Sub Saharan Africa ◽  
Tropical Maize ◽  
Training Set ◽  
Maize Weevil ◽  
Maize Resistance ◽  
Sub Saharan

Genomic selection (GS) can accelerate variety release by shortening variety development phase when factors that influence prediction accuracies (PA) of genomic prediction (GP) models such as training set (TS) size and relationship with the breeding set (BS) are optimized beforehand. In this study, PAs for the resistance to fall armyworm (FAW) and maize weevil (MW) in a diverse tropical maize panel composed of 341 double haploid and inbred lines were estimated. Both phenotypic best linear unbiased predictors (BLUPs) and estimators (BLUEs) were predicted using 17 parametric, semi-parametric, and nonparametric algorithms with a 10-fold and 5 repetitions cross-validation strategy. n. For both MW and FAW resistance datasets with an RBTS of 37%, PAs achieved with BLUPs were at least as twice as higher than those realized with BLUEs. The PAs achieved with BLUPs for MW resistance traits: grain weight loss (GWL), adult progeny emergence (AP), and number of affected kernels (AK) varied from 0.66 to 0.82. The PAs were also high for FAW resistance RBTS datasets, varying from 0.694 to 0.714 (for RBTS of 37%) to 0.843 to 0.844 (for RBTS of 85%). The PAs for FAW resistance with PBTS were generally high varying from 0.83 to 0.86, except for one dataset that had PAs ranging from 0.11 to 0.75. GP models showed generally similar predictive abilities for each trait while the TS designation was determinant. There was a highly positive correlation (R=0.92***) between TS size and PAs for the RBTS approach while, for the PBTS, these parameters were highly negatively correlated (R=-0.44***), indicating the importance of the degree of kinship between the TS and the BS with the smallest TS (31%) achieving the highest PAs (0.86). This study paves the way towards the use of GS for maize resistance to insect pests in sub-Saharan Africa.

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