CGIAR Initiative on Plant Health

Permanent URI for this collectionhttps://hdl.handle.net/10568/117901

Part of the CGIAR Action Area on Resilient Agrifood Systems

Primary CGIAR impact area: Nutrition, health and food security

https://www.cgiar.org/initiative/13-plant-health-and-rapid-response-to-protect-food-and-livelihood-security/

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Now showing 1 - 20 of 428

Spent Pleurotus ostreatus substrate has potential for controlling the plant-parasitic nematode, Radopholus similis in bananas
(Journal Article, 2025-04-26) Tazuba, Anthony Fredrick; Ocimati, Walter; Ogwal, Geofrey; Nyangwire, Betty; Onyilo, Francis; Blomme, Guy
Spent mushroom substrate (SMS), a waste product from mushroom cultivation, in addition to being rich in essential nutrients for crop growth, contains actively growing mushroom mycelia and metabolites that suppress some plant pathogens and pests. SMS thus has potential for fostering the suppressiveness of soil-borne pathogens of farms. This study determined the potential of using the spent Pleurotus ostreatus substrate (SPoS) to suppress the plant-parasitic nematode Radopholus similis in bananas. R. similis is the most economically important nematode in bananas worldwide. The effect of SPoS on R. similis was assessed through two in vivo (potted plants) experiments between May 2023 and June 2024. Five-month-old East African highland banana (genome AAA) plantlets that are highly susceptible to R. similis were used. In the first experiment, the plantlets were established in 3 L pots containing (i) pre-sterilized soil, (ii) pre-sterilized soil inoculated with nematodes, (iii) pre-sterilized soil mixed with 30% (v/v) SPoS, (iv) pre-sterilized soil mixed with 30% (v/v) SPoS followed by nematode inoculation, (v) SPoS without soil, and (vi) SPoS without soil inoculated with nematodes. The SPoS was already decomposed; thus, it may or may not have contained active mycelia. The nematodes were introduced two weeks after the SPoS application. In the second experiment, SPoS was introduced two weeks after nematode inoculation. The SPoS treatments without soil were not evaluated in the second experiment. Both experiments were monitored over a three-month period. Each screenhouse treatment contained four plants and was replicated thrice. In the first experiment, data were collected on changes in soil nutrient content, below- and aboveground biomass, root deaths, root necrosis due to nematode damage, and R. similis population in root tissues and soil. In the second experiment, data were collected on root deaths and the number of nematodes in root tissues and the soil. The SPoS improved crop biomass yield, reduced root damage, and colonization by R. similis. The potential of SPoS to improve the management of R. similis and banana production under field conditions needs to be determined.
Pathogenicity of entomopathogenic Beauveria bassiana strains on Helicoverpa armigera (Hübner)
(Journal Article) Boulamtat, Rachid; El-Fakhouri, Karim; Jaber, Hassna; Oubayoucef, Ali; Ramdani, Chaimae; Fikraoui, Nabil; Al-Jaboobi, Muamar; El Fadil, Meryem; Maafa, Ilyass; Mesfioui, Abdelhalem; Kemal, Seid Ahmed; El Bouhssini, Mustapha
The destructive pest of chickpeas, Helicoverpa armigera (Hübner), is difficult to control using synthetic insecticides. The current research examined the entomopathogenic and endophytic colonisation effects of three fungal strains of Beauveria bassiana (HASS; RFSL10; SP-IR-566) against H. armigera larvae under laboratory, greenhouse, and field conditions. Four inoculation methods were used in the greenhouse: Root Dipping (RD), Leaf Spraying (LS), Stem Injection (SI), and Seed Coating (SC), while spray application was used for laboratory and field treatments. Under laboratory conditions, the highest entomopathogenic effect was recorded by HASS and RFSL10 strains applied as a direct spray at 108 conidia mL-1 with 100% mortality, followed by SP-IR-566 with 96%, 12 days after treatment. Furthermore, foliar application in the field reduced larval population by an average ranging from 82 to 100%, confirming the significant effects of the three tested strains. In terms of endophytic colonisation under greenhouse setting, both stem injection and root dipping methods expressed low to moderate mortality rates ranging from 32 to 40%, 15 days after application. These findings suggested that B. bassiana strains, investigated as foliar application, had a potential as an effective strategy to control H. armigera. This study also offers new insights into the potential of the endophytic entomopathogens approach as a viable and safe alternative to chemical pesticides.
Combating aflatoxin contamination by combining biocontrol application and adapted maize germplasm in northeastern and southeastern Mexico
(Journal Article, 2025-05) Muñoz-Zavala, Carlos; Molina Macedo, Aide; Toledo, Fernando H.; Telles Mejía, Eugenio; Cabrera-Soto, Luisa; Palacios-Rojas, Natalia
Maize is highly vulnerable to aflatoxin (AF) contamination caused by fungi from the Aspergillus section Flavi, with deficiencies in post-harvest management practices further exacerbating AF levels. Due to their carcinogenic properties, AFs pose significant health risks. Biological control using non-aflatoxigenic A. flavus isolates has been effective for over 25 years in the USA, with two formulations being commercially available. However, no such products have been developed yet for use in Mexico. This study evaluated the effectiveness of AF36-Prevail®, a non-aflatoxigenic strain from Arizona, for reducing aflatoxin contamination in Mexico. Over four years (2019–2022), we assessed its impact alongside regionally adapted maize germplasm in northeastern and southeastern Mexico. We analyzed a total of 1,479 grain samples, with 887 from biocontrol-treated fields, and 592 from untreated fields across 69 sites in Tamaulipas and Campeche. Treated fields showed 59.0 % to 89.9 % reductions in AF content compared to untreated fields, and higher ear rot was observed in untreated fields. Correlation coefficients between ear rot and AF content were r = 0.08 for Campeche and r = 0.36 for Tamaulipas. Significant differences (p ≤ 0.001) were noted between years and hybrids for both yields and AF levels. Three hybrids in Tamaulipas and four in Campeche demonstrated better adaptation, higher yields, and lower AF levels (< 20 ppb). This research underscores the potential for safer maize production in Mexico, particularly when combining biocontrol strain application with adapted germplasm.
P40: Rate of seed transmission of bean common mosaic virus (BCMV) in successive generations in cowpea
(Abstract, 2025) Dauda, N.; Ajamu, D.; Baiyeri, P.K.; Ugwuoke, K.I.; Kumar, P.L.
This study aimed to understand the effect of genotype, time of infection, and seed morphometrics on seedborne virus infections in cowpea (Vigna unguiculata) transmission and the eventual impact of seed-borne viruses on cowpea yield compared to uninfected control. Experiments were performed using a Potyvirus species, bean common mosaic virus-blackeye (BCMV-BlCM). This virus is endemic in West Africa. Nine cowpea genotypes raised in 6-inch pots and maintained in an insect-proof screenhouse were mechanically inoculated at 7, 21, and 40 days after planting (DAP). Seeds obtained from both the inoculated and uninoculated control groups were planted, and the seedlings were examined for seedborne infection based on symptoms and RT-PCR diagnostics. All identified seed-borne plants were maintained until harvest and re-evaluated for seed transmission and the impact of seedborne viruses on cowpea yield in successive generations. In the first generation, percent BCMV seed transmission rates of 7.9, 4.6, and 44.4 were observed in genotypes RS018 inoculated at 21 DAP, RS075 (7 DAP), and RS012 (DAP). In the second generation, 35.1%, 0%, and 34.1% transmission rates were reported for the same genotypes. Significant reduction in seed yield and prolonged days to phenology was observed in seedborne plants when compared to uninfected controls. Early-stage protection against virus infection will reduce the risk of seed transmission in cowpeas.
Implications of high throughput sequencing of plant viruses in biosecurity – a decade of progress?
(Abstract, 2025) Fox, A.; Botermans, M.; Ziebell, H.; Fowkes, A.R.; Fontdevila, N.; Massart, S.; Rodoni, B.; Chooi, K.M.; Kreuze, J.; Kumar, P.L.; Cuellar, W.J.; Carvajal-Yepes, M.; Macdiarmid, R.M.
In the 15 years since High Throughput Sequencing (HTS) was first used for the detection and identification of plant viruses, the technology has matured and is now being used in frontline plant biosecurity applications. Anticipating the challenges this new approach was starting to reveal, recommendations were made a decade ago to streamline the application of these technologies (MacDiarmid et al., 2013). The recommendations were (1) for countries to increase baseline surveillance, (2) to address nomenclature for “data inferred” new viral sequence to differentiate from characterised viruses, and (3) to increase the focus on fundamental biological research to deal with the deluge of new virus discoveries. The progress made on these recommendations in the intervening decade has been as much about changing philosophical approaches as about advancing practical research. As we move towards a potential asymptote in the rate of virus discovery, the anticipated future challenges posed by the broader adoption of HTS in routine biosecurity applications need to be considered. In addition to these three recommendations, which remain relevant, a fourth recommendation is becoming necessary: (4) to ensure equal inclusion and access to research and technology, both locally and globally, with a particular emphasis on countries in the global south. The potential impact of these recommendations on researchers, risk analysts, biosecurity authorities, and policymakers at national and international levels to achieve a reduction of biosecurity incursions of phytopathogenic viruses will be discussed.
CGIAR Research Initiative on Plant Health: Annual Technical Report 2024
(Report, 2025-04-15) CGIAR Initiative on Plant Health
Expert insight: combating Banana Bunchy Top Disease (BBTD) an interview with IITA's plant pathology
(Video, 2024-12-11) International Institute of Tropical Agriculture
From 3rd to 4th October 2024, 71 stakeholders, including 41 smallholder farmers from the districts of Bushenyi, Rubirizi, Bunyangabu and Kasese districts, staff from IITA, ASARECA, Plant Health Initiative, MAAIF, NARO, Extension Agents, and local policy makers gathered in Kasese district for a comprehensive 2-day learning experience about the emerging BBTD caused by the invasive Banana Bunchy Top Virus (BBTV). Field demonstrations on disease identification, sanitation, and control measures, farmer-to-farmer sharing of experiences and successes, expert presentations on BBTD biology, symptoms, and management, and interactive sessions on integrated pest management (IPM) strategies, empowered farmers with the necessary knowledge and skills on BBTD symptoms and transmission, including how to recognize infected plants, the importance of early detection and removal of infected plants, disease prevention and management strategies and knowledge on clean planting materials. Farmers were also able to witness and appreciate the impact of BBTD through experience from farmers in Kasese.
Combating Banana Bunchy Top Disease (BBTD): healthy banana harvest
(Video, 2024-12-12) International Institute of Tropical Agriculture
From 3rd to 4th October 2024, 71 stakeholders, including 41 smallholder farmers from the districts of Bushenyi, Rubirizi, Bunyangabu and Kasese districts, staff from IITA, ASARECA, Plant Health Initiative, MAAIF, NARO, Extension Agents, and local policy makers gathered in Kasese district for a comprehensive 2-day learning experience about the emerging BBTD caused by the invasive Banana Bunchy Top Virus (BBTV). Field demonstrations on disease identification, sanitation, and control measures, farmer-to-farmer sharing of experiences and successes, expert presentations on BBTD biology, symptoms, and management, and interactive sessions on integrated pest management (IPM) strategies, empowered farmers with the necessary knowledge and skills on BBTD symptoms and transmission, including how to recognise infected plants, the importance of early detection and removal of infected plants, disease prevention and management strategies and knowledge on clean planting materials. Farmers were also able to witness and appreciate the impact of BBTD through experience from farmers in Kasese.
Combating Banana Bunchy Top Disease (BBTD): the farmer’s experience
(Video, 2024-12-12) International Institute of Tropical Agriculture
From 3rd to 4th October 2024, 71 stakeholders, including 41 smallholder farmers from the districts of Bushenyi, Rubirizi, Bunyangabu and Kasese districts, staff from IITA, ASARECA, Plant Health Initiative, MAAIF, NARO, Extension Agents, and local policy makers gathered in Kasese district for a comprehensive 2-day learning experience about the emerging BBTD caused by the invasive Banana Bunchy Top Virus (BBTV). Field demonstrations on disease identification, sanitation, and control measures, farmer-to-farmer sharing of experiences and successes, expert presentations on BBTD biology, symptoms, and management, and interactive sessions on integrated pest management (IPM) strategies, empowered farmers with the necessary knowledge and skills on BBTD symptoms and transmission, including how to recognize infected plants, the importance of early detection and removal of infected plants, disease prevention and management strategies and knowledge on clean planting materials. Farmers were also able to witness and appreciate the impact of BBTD through experience from farmers in Kasese.
Combating Banana Bunchy Top Disease (BBTD): the farmer’s experience
(Video, 2024-12-12) International Institute of Tropical Agriculture
From 3rd to 4th October 2024, 71 stakeholders, including 41 smallholder farmers from the districts of Bushenyi, Rubirizi, Bunyangabu and Kasese districts, staff from IITA, ASARECA, Plant Health Initiative, MAAIF, NARO, Extension Agents, and local policy makers gathered in Kasese district for a comprehensive 2-day learning experience about the emerging BBTD caused by the invasive Banana Bunchy Top Virus (BBTV). Field demonstrations on disease identification, sanitation, and control measures, farmer-to-farmer sharing of experiences and successes, expert presentations on BBTD biology, symptoms, and management, and interactive sessions on integrated pest management (IPM) strategies, empowered farmers with the necessary knowledge and skills on BBTD symptoms and transmission, including how to recognize infected plants, the importance of early detection and removal of infected plants, disease prevention and management strategies and knowledge on clean planting materials. Farmers were also able to witness and appreciate the impact of BBTD through experience from farmers in Kasese.
How soon is now? Tackling Africa’s recurrent aflatoxin crises through integrated, multi-sectoral management strategies
(Brief, 2025-03) Ortega-Beltran, A.; Bandyopadhyay, R.; Ehui, S.
Seasonal and spatial distribution of fall armyworm larvae in maize fields: implications for integrated pest management
(Journal Article, 2025-02-01) Zanzana, K.; Sinzogan, A.; Tepa-Yotto, G.; Dannon, E.; Goergen, G.; Tamo, M.
The fall armyworm (FAW), Spodoptera frugiperda, a major pest in maize production, was assessed for its temporal and spatial distribution in maize fields during both the dry and rainy seasons of 2021 and 2022 in two agroecological regions in Benin (zone 6 and 8). Zone 6 (AEZ 6) “called zone of terre de barre” (Southern and Central Benin) consisted of ferralitic soils, a Sudano-Guinean climate (two rainy seasons alternating with two dry seasons) with a rainfall ranging between 800 and 1400 mm of rainfall per year; while zone 8 (AEZ 8) called “fisheries region” (Southern Benin” is characterized by coastal gleysols and arenosols with a Sudano-Guinean climate and a rainfall of 900–1400 mm of rainfall per year. In this study, 30 and 50 maize plants were randomly sampled using a “W” pattern during the dry and rainy seasons, respectively. Larval density, larval infestation rates, and damage severity were monitored over time. Taylor’s power law and the mean crowding aggregation index were applied to evaluate the dispersion patterns of the larvae. The results indicate a higher larval infestation rate and larval density in AEZ 8 compared to AEZ 6 during the dry season. In the rainy season, while the percentage of damaged plants was higher in AZE 8, no significant differences in larval density between the two zones were observed. The dispersion analysis revealed moderate aggregation (aggregation index = 1.25) with a basic colony of 2.08 larvae, i.e., an average initial cluster of 2.08 larvae observed per plant, reflecting the aggregation oviposition behavior of FAW. This study provides valuable monitoring data on the FAW’s distribution, offering insights for further research on population dynamics and developing predictive models for integrated pest management strategies.
Risk assessment of black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae composting for circular waste management in southern Benin
(Journal Article, 2025) Ogbon, E.A.; Dzepe, D.; Lalander, C.; Wiklicky, V.; Sinda, P.V.K.; Adeoti, R.; Mignouna, D.; Gbaguidi, B.; Behanzin, J.G.; Riggi, L.; Djouaka, R.
Insect farming is becoming an important business in West Africa, and the black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) is one of the most widely farmed species. In this study, we investigated the potential risk factors, including heavy metals and pesticides, of the implementation of black soldier fly (BSF)-based technology for circular waste management in the context of Benin. The study was performed in two phases. In Phase 1, we identified and estimated the primary sources of biowaste streams suitable for BSF rearing in Benin. The study involved identifying these sources, estimating their availability, and analysing their characteristics, particularly in terms of contamination levels. In Phase 2, each identified biowaste streams was subjected to BSF larvae treatment and the levels of identified contaminants was analysed before and after the treatment, as well as some microbial contaminants such as Salmonella spp. and Escherichia coli and yeasts and moulds. The majority of biowaste streams and derived BSF larvae were contaminated with copper, chromium, cadmium, lead, and zinc. However, the concentrations detected were below the standard limit values recommended for animal feed. Traces of pesticides were detected in all biowaste streams and derived frass. No pesticide contamination was detected in BSF larvae. Salmonella spp. was found to be the most predominant pathogenic microorganism in fresh BSF larvae as well as in the frass. We therefore recommended to sanitiInsect farming is becoming an important business in West Africa, and the black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) is one of the most widely farmed species. In this study, we investigated the potential risk factors, including heavy metals and pesticides, of the implementation of black soldier fly (BSF)-based technology for circular waste management in the context of Benin. The study was performed in two phases. In Phase 1, we identified and estimated the primary sources of biowaste streams suitable for BSF rearing in Benin. The study involved identifying these sources, estimating their availability, and analysing their characteristics, particularly in terms of contamination levels. In Phase 2, each identified biowaste streams was subjected to BSF larvae treatment and the levels of identified contaminants was analysed before and after the treatment, as well as some microbial contaminants such as Salmonella spp. and Escherichia coli and yeasts and moulds. The majority of biowaste streams and derived BSF larvae were contaminated with copper, chromium, cadmium, lead, and zinc. However, the concentrations detected were below the standard limit values recommended for animal feed. Traces of pesticides were detected in all biowaste streams and derived frass. No pesticide contamination was detected in BSF larvae. Salmonella spp. was found to be the most predominant pathogenic microorganism in fresh BSF larvae as well as in the frass. We therefore recommended to sanitise all BSF larvae that are intended for use in animal feed. As was demonstrated in this study, no Salmonella spp. was found in the sanitised larvae. The findings of this study will promote the establishment of safety measures in the BSF farming sector.se all BSF larvae that are intended for use in animal feed. As was demonstrated in this study, no Salmonella spp. was found in the sanitised larvae. The findings of this study will promote the establishment of safety measures in the BSF farming sector.
Soil organic carbon and nutrient content across agricultural systems in the forest-savannah transition zone of Cameroon
(Journal Article, 2025) Mandah, V.P.; Masso, C.; Onana, A.A.; Fiaboe, K.; Arthur, E.; Giweta, M.; Ndango, R.; Silatsa, F.B.T.; Voulemo, D.D.I.; Biloa, J.B.; Ngeumezi, C.; Tematio, P.
Accurate knowledge of soil characteristics is indispensable for large-scale agriculture while ensuring sustainability, climate change adaptation, and mitigation, which is lacking in Cameroon. This study aimed to assess soil organic carbon (SOC) and nutrient (NPK) content across agricultural systems in the forest-savannah transition zone of Cameroon. Seven agricultural systems were identified namely: the forest-based cocoa agroforestry (Fcocoa), savannah-based cocoa agroforestry (Scocoa), transition zone-based cocoa agroforestry (Tcocoa), savannah mixed cropping of yam, pumpkin, and maize (Sypm), savannah mixed cropping of groundnut, cassava and maize (Sgcm), transition zone mixed cropping of yam, pumpkin, and maize (Typm), and the transition zone mixed cropping of groundnut, cassava, and maize (Tgcm). The soil was sampled at two depths, 0–10 cm (upper layer) and 10–30 cm (lower layer) in three replicates for each farming system and analyzed. Significant differences appeared in soil organic carbon (SOC) (p < 0.002), Total nitrogen (N) (p < 0.001), C:N ratio (p < 0.002), pH (p < 0.01), bulk density (Bd) (p < 0.03), soil organic carbon stock (SOCS) (p < 0.001), and soil nitrogen stock (SNS) (p < 0.001). In the upper and lower layers, the highest concentrations of SOC (25.0 and 16.6 g kg−1), N (2.3 and 1.5 g kg−1), and P (5.1 and 3.3 g kg−1) were recorded in Fcocoa, and K (176.9 and 129.3 mg kg−1) in Scocoa respectively. In the croplands, soil nutrient content was higher in the transition zone while savannah croplands showed higher Bd (≥ 1.4 g cm−3). Soil nutrient content decreased from upper to lower soil layers with a significant difference (p < 0.05) in the croplands for pH, SOCS, and SNS, with a higher magnitude (p < 0.01) in Sgcm. Thus, agroforestry can be considered a potential solution towards ecological resilience.
Combating banana bunchy top disease: an interview with the Kasese district agricultural officer
(Video, 2024-12-12) International Institute of Tropical Agriculture
From 3rd to 4th October 2024, 71 stakeholders, including 41 smallholder farmers from the districts of Bushenyi, Rubirizi, Bunyangabu and Kasese districts, staff from IITA, ASARECA, Plant Health Initiative, MAAIF, NARO, Extension Agents, and local policy makers gathered in Kasese district for a comprehensive 2-day learning experience about the emerging BBTD caused by the invasive Banana Bunchy Top Virus (BBTV). Field demonstrations on disease identification, sanitation, and control measures, farmer-to-farmer sharing of experiences and successes, expert presentations on BBTD biology, symptoms, and management, and interactive sessions on integrated pest management (IPM) strategies, empowered farmers with the necessary knowledge and skills on BBTD symptoms and transmission, including how to recognize infected plants, the importance of early detection and removal of infected plants, disease prevention and management strategies and knowledge on clean planting materials. Farmers were also able to witness and appreciate the impact of BBTD through experience from farmers in Kasese.
A seed system approach to enhance virus disease management invegetatively propagated crops in sub-Saharan Africa
(Abstract, 2025-01) Kumar, P.L.; Aighewi, B.; Balogun, M.; Diebiru-Ojo, E.; Amah, D.; Mignouna, D.; Fiaboe, K.K.M.; Mahuku, G.; Legg, J.P.
Develop risk assessment and preparedness/ biosecurity plans to limit entry of seed borne diseases of phytosanitary importance
(Report, 2024-01-29) Onaga, G.
Developing and implementing biosecurity plans is the most effective way to protect against exotic pests and diseases. Biosecurity involves the proactive measures taken to prevent and manage pests and diseases that have not yet entered a country or a region but are anticipated to do so, whether through seasonal patterns or natural means such as seed importation, trade, or wind dispersal. A Biosecurity Preparedness Plan (BPP) plays a crucial role in managing the risk and impact of the introduction or spread of new pests that pose biosecurity risks. BPPs are important to ensure that NPPOs effectively minimize the biosecurity risks associated with international exchange of rice germplasm, which is crucial for germplasm improvement and food security. AfricaRice conducted workshops in partnership with NPPOs from Cote d’Ivoire and Uganda to ensure that both countries develop BPPs effectively to reduce the biosecurity risks linked to the international exchange of rice germplasm. The initial workshop focused on formulating practical strategies for addressing biosecurity risks linked to the importation of rice germplasm. The emphasis was on showcasing key updates in phytosanitary laws and regulations, pinpointing priority pests and diseases linked to rice, detailing detection and diagnosis techniques, evaluating control and eradication strategies, and deliberating on effective awareness and communication strategies, alongside pertinent policies and standards for the countries involved. A biosecurity preparedness evaluation questionnaire was also developed as part of it. The second workshop focussed on formulating preliminary rice biosecurity plans for the importation of rice germplasm into Uganda and Ivory Coast. The Uganda workshop achieved its intended outcomes in 2024. The Cote d’Ivoire workshop did not; however, there are plans to organize it in 2025.
Eco-friendly and climate smart biopesticides developed and evaluated for their efficacy on target pests
(Report, 2024) Nwilene, F.; Adeoti, A.; Nacro, S.; Ouattara, D.; Umaru, A.; Oladigbolu, A.
Insect pests such as the rice stem borers (African rice gall midge (AfRGM) Orseolia oryzivora, and Diopsis spp.) are among the economically most important pests of rainfed upland/lowland and irrigated rice in Sub-Saharan Africa. The African rice gall midge, Orseolia oryzivora Harris & Gagné (Diptera: Cecidyomyiidae), is an insect pest primarily of rainfed and irrigated lowland rice, and occurs only in sub-Saharan Africa. The larvae cause severe crop damage during the vegetative stages (seedling to panicle initiation) by producing tube-like ‘silver shoot’ or ‘onion leaf’ galls that prevent panicle production. Dipterous stem borers (the stalk-eyed flies – Diopsis spp.) are the most economically important stem borer species of rainfed upland/lowland and irrigated rice in Nigeria. The larvae of stem borers cause significantly yield loss during the vegetative (seedlings to panicle initiation) and reproductive stages by producing deadhearts and whiteheads, respectively, which prevent panicle development. The extensive use of synthetic insecticides to control these pests has raised concerns regarding environmental and human health. Consequently, this has necessitated the need for alternative control measures such as biopesticides. Identifying the use of biopesticides such as botanicals and Entomopathogenic fungi are most promising options for managing AfRGM and stem borers on rice.
Phylogenetic analysis, mixed infection and seed transmission of Pea seed-borne mosaic virus in Ethiopia
(Journal Article, 2025-01-16) Ademe, Anteneh; Kumari, Safaa; Moukahel, Abdulrahman; Alemu, Tesfaye; Abraham, Adane; Aynewa, Yetsedaw; Guadie, Demsachew; Kemal, Seid Ahmed
Pea seed-borne mosaic virus (PSbMV) is a significant pathogen affecting the yield and quality of lentil and chickpea crops in Ethiopia's major legume-producing regions, Amhara and Oromia. This study focuses on characterizing PSbMV and its seed transmission rates, including mixed infections under field conditions. Tissue blot immunoassay (TBIA) analysis revealed that 56.2 % of tested lentil and chickpea samples were infected with PSbMV, often in mixed infections. PSbMV seed transmission rates varied widely among tested lentil genotypes, with the widely grown improved lentil cultivar Alemaya (FLIP 89-63 L) showing a transmission rate as high as 13.5 %. To characterize the isolates, the partial polyprotein gene was amplified and sequenced. Analysis of these sequences showed nucleotide identities ranging from 90.5 % to 100 %. Phylogenetic analysis classified Ethiopian PSbMV isolates (from lentil and chickpea) into four major clades and four subclades. Five lentil isolates (EthLe204-18, EthLe547-18, EthLe12-19, EthLe84-19, and EthLe214-33-19) and one chickpea isolate (EthCp115-19) clustered in subgroup BI, while isolate EthLe343-18 clustered into subgroup BII with an American pathotype-2 isolate (AJ252242). Isolates EthLe7-21 and EthLe381-21 clustered with an Australian P-2 isolate (HQ185579) into group D. Further analysis using RDP indicates intraspecific recombination only in isolate EthLe214-19, with fragments derived from EthLe343-18 and EthLe204-18 as major and minor parents, respectively. No recombination events were detected in the other isolates. This study suggests that variations in lentil genotype resistance to seed infection could be leveraged for resistance breeding, and the impacts of mixed infections on lentil crops warrant further investigation.
Detection and Partial Characterization of Polerovirus and Luteovirus Isolates Associated With Lentil and Chickpea in Ethiopia
(Journal Article, 2025-02-05) Ademe, Anteneh; Kumari, Safaa; Moukahel, Abdulrahman; Alemu, Tesfaye; Abraham, Adane; Aynewa, Yetsedaw; Guadie, Demsachew; Kemal, Seid Ahmed
The partial nucleotide sequence of the coat protein (CP) gene of Ethiopian isolates of chickpea chlorotic stunt virus (CpCSV, genus Polerovirus), beet western yellows virus (BWYV, genus Polerovirus), and soybean dwarf virus (SbDV, genus Luteovirus) was determined from lentil and chickpea plants showing yellowing, stunting, and reddening symptoms. Comparative sequence analysis of CpCSV isolates obtained from five chickpea and five lentil isolates showed 94.9%–100% and 91.9%–98.7% nucleotide sequence identity with each other and with the reference isolates, respectively. One CpCSV isolate from chickpea (MZ043728) showed a close relationship with isolates of the serotype II while the remaining nine isolates were closely related to isolates belonging to serotype I. Sequence identities of three chickpea BWYV isolates varied from 93.3% to 100% with the reference isolates, and one of them (MZ043727) displayed 100% nucleotide identity with previously reported lentil stunt virus (LStV, genus Polerovirus). The chickpea isolates MZ043725 and MZ043726 appear to be identical to each other, whereas the other isolate (MZ043727) was identical to previously identified LStV isolate. The nucleotide sequence of three Ethiopian SbDV isolates had a lower identity with GenBank isolates and their phylogenetic analysis showed that they are clustered separately from the rest of the reference isolates indicating that they are the most divergent. This result generates essential information for further research on legume viruses in Ethiopia. In addition, a detailed study should be conducted in the future to understand the prevalence of LStV and determine the potential yield losses associated with the virus in Ethiopia.

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