Phytophthora megakarya

Phytophthora megakarya Black Pod Rot Abstract: Both abiotic (climate change) and biotic (endemic pests and pathogens) stresses threaten African cocoa production. However, black Pod Rot (BPR) disease, caused by Phytophthora megakarya, is of particular concern to farmers and researchers because since the beginning in the …

Premise of the study: Phytophthora megakarya is the agent of black pod disease of cacao and is the main pathogen of this crop in Africa. Population genetic studies are required to investigate how this pathogen emerged. To this end, we developed 12 novel polymorphic microsatellite markers for P. megakarya.Phytophthora megakarya the causative agent of cacao from being very expensive for many African farmers, black pod disease is present only in Central and West African cocoa producing countries, and is the most damaging of the cocoa diseases in this region. Annual losses due to this disease range from 30 to 90% of total ...Analysis of expressed sequence tags (ESTs) from cocoa (Theobroma cacao L) upon infection with Phytophthora megakaryaP.megakarya genomeisestimatedat126.9Mbpandthe P.palmivora genome is estimated at 151.2 Mb. Both genomes carry large gene numbers (42,036 and 44,327 for P. megakarya and P. palmivora, respectively), compared with other Phytophthora species, a clear indication of their apparently complex genome compositions.Bioassay of Geniculosporium species for Phytophthora megakarya biological control on cacao pod husk piecesNatural occurrence and distribution of stem cankers caused by Phytophthora megakarya and Phytophthora palmivora on cocoaAmong the Phytophthora species that cause black pod of cacao, P. megakarya is the most virulent, posing a serious threat to cacao production in Africa. Correct identification of the species causing the black pod and understanding the virulence factors involved are important for developing sustainable disease management strategies.Christian Nembot, Patrice Takam Soh, Gerben Martijn Hoopen, Yves Dumont, Modeling the temporal evolution of cocoa black pod rot disease caused by Phytophthora megakarya, Mathematical Methods in the Applied Sciences, 10.1002/mma.5206, 41, 18, (8816-8843), (2018).

Two well-established diseases cause the greatest losses: black pod rot, caused by several species of Phytophthora, and witches’ broom of cacao, caused by Moniliophthora perniciosa. Phytophthora megakarya causes the severest damage in the main cacao producing countries in West Africa, while P. palmivora causes significant losses globally. A severe black pod disease of cocoa in Ghana caused by Phytophthora megakarya was first reported in 1985, even though there is evidence that the fungus might have existed earlier. Until then, only Phytophthora palmivora which causes a less severe black pod disease was known in Ghana. P. megakarya has changed the status of black pod disease in Ghana, causing serious crop losses and great ...EFFET DES TRAITEMENTS DU SOL SUR LE DEVELOPPEMENT DE L'EPIDEMIE DE LA POURRITURE BRUNE (Phytophthora megakarya) DU CACAOYER AU CAMEROUN . × Close Log In. Log in with Facebook Log in with Google. or. Email. Password. Remember me on this computer. or reset password. Enter the email address you signed up with and we'll email you a reset link. ...Black pod rot of cocoa caused by Phytophthora megakarya causes significant losses in Cameroon. Normally (chemical) control efforts only begin when the first diseased pods appear. In theory, preventive control, focusing on reducing primary inoculum or2018年10月12日 ... (2008). Bioassay of five trichoderma strains against Phytophthora megakarya (Cacao pod-rot) in Nigeria. Scientific Research and Essays, 3(9), ...1.. IntroductionTwo species of Phytophthora, P. palmivora and P. megakarya are the main causal pathogens of black pod disease of cocoa in West Africa.P. palmivora has been reported on a large number of host plants. Ashby (1929) described P. palmivora as an omnivorous tropical fungal pathogen of world-wide distribution, existing as a number …Phytophthora megakarya was first reported in 1985, even though there isevidence that the fungus might have existed earlier. Until then. only Phytophlhora palmivora which'

Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa losses in Cameroon.A few studies have focused on describing black pod epidemics in cocoa yet numerous questions remain. Here, an epidemiological model describing the temporal evolution of cocoa black pod, taking into account the development stages of pods, is developed and studied.Phytophthora megakarya plugs from 3-days preculture was placed at the centre of V8 agar plate. The antimicrobial activities were done according to the method describe by Vinale et al. (2006). The crude organic extract was diluted in Dimethyl Sulfoxide (DMSO) at the concentration ranging from 25 to 100μg/ml/l/ and 10μl of each concentration ...inoculum of Phytophthora megakarya (causal agent of cacao black pod rot disease) upon establishment in 2006 were monitored for pres-ence of disease on a weekly basis from 2009 to 2016. Ripley’s K(r) function, join count statistics, and Fisher’s Exact test were used to analyze spatial and temporal disease dynamics. Disease distributionCocoa (Theobroma cacao L.) black pod rot, caused by oomycetes Chromista Phytophthora megakarya is the major constraint to cocoa production in Cameroon, causing substantial yield losses (up to 100%). As mean to alter the yield shortage, priority is given to chemical fungicides, though Arbuscular Mycorrhizals Fungi (AMF) have been pointed out to offer a friendly alternative. Moreover, exudation ...The genus Phytophthora has been studied at the cellular level, suggesting that different developmental steps are induced by the expression of some specific genes. However, these studies have only been carried out on certain species, such as Phytophthora infestans and Phytophthora cactorum. ... Phytophthora megasperma and Phytophthora megakarya ...

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Studying spatial and temporal plant disease dynamics helps to understand pathogen dispersal processes, a necessary undertaking in epidemiology in order to improve disease control recommendations. In this study, plantations devoid of primary inoculumPhytophthora megakarya appears to be confined to West Africa (Zentmeyer, 1987), where it is the most common species of Phytophthora causing black pod disease of cocoa. Theobroma cacao (cocoa) is ...In subtropical countries, black pod caused by Phytophthora megakarya is one of the main diseases causing drastic losses of cocoa. The synthetic chemicals used to control the pathogen, although ...Black pod disease caused by Phytophthora megakarya is the most important fungal disease on cocoa in Ghana. The current recommended control method of combining sanitation practices with 6 - 8 ...Cocoa (Theobroma cacao L.) black pod rot, caused by oomycetes Chromista Phytophthora megakarya is the major constraint to cocoa production in Cameroon, causing substantial yield losses (up to 100%). As mean to alter the yield shortage, priority is given to chemical fungicides, though Arbuscular Mycorrhizals Fungi (AMF) have been pointed out to offer a friendly alternative. Moreover, exudation ...

Download Table | Phytophthora megakarya growth inhibition by Syzygium arom- aticum and Zanthoxylum xanthoxyloides essential oils at various con- centrations from publication: Antimicrobial ...Phytophthora megakarya is an increasingly important invasive pathogen of cocoa in West Africa, where it forms part of the black-pod disease complex together with the more widespread, but less aggressive, P. palmivora.Its purported centre of diversity, based on evidence from molecular studies and mating types, lies on the Cameroon-Nigeria border, from where it has spread throughout both ...Phytochemical screening and antifungal activity of Chromolaena odorata extracts against isolate of Phytophthora megakarya using agar-well diffusion method. AI Adeyemi, OI Vincent, OM Olujenyo. Asian Journal of Medical and Biological Research 4 …Phytophthora megakarya is an increasingly important invasive pathogen of cocoa in West Africa, where it forms part of the black-pod disease complex together with the more widespread, but less ...Phytophthora megakarya Taxonomy ID: 4795 (for references in articles please use NCBI:txid4795) current name. Phytophthora megakarya. type material of Phytophthora megakarya: ATCC:42100, CBS:238.83, IMI:202077. NCBI BLAST name: downy mildews Rank: species Genetic code: Translation table 1 (Standard)Phytophthora megakarya Taxonomy ID: 4795 (for references in articles please use NCBI:txid4795) current name. Phytophthora megakarya. type material of Phytophthora megakarya: ATCC:42100, CBS:238.83, IMI:202077. NCBI BLAST name: downy mildews Rank: species Genetic code: Translation table 1 (Standard)Abstract. A severe black pod disease of cocoa in Ghana caused by Phytophthora megakarya was first reported in 1985, even though there is evidence that the fungus might have existed earlier. Until ...The considerable economic and social impact of the oomycete genus Phytophthora is well known. In response to evidence that all downy mildews (DMs) reside phylogenetically within Phytophthora, rendering Phytophthora paraphyletic, a proposal has been made to split the genus into multiple new genera. We have reviewed the status of the genus and its relationship to the DMs. Despite a substantial ...cocoa-tree and the biocontrol of Phytophthora megakarya, which is the most aggressive agent of black pod disease. Five strains of phosphate solubilizing bacteria (PSB) were characterized on petri ...

Phytophthora megakarya is an important pathogen of cocoa in Africa. We used isozyme and RAPD markers to estimate the genetic diversity and structuring among 161 isolates, from the known ...

process against Phytophthora megakarya Minyaka Emile 1,4* , Simo Claude 3,4 , Mouen Piau Jean Cyrille 1,2 , Madina Banen Colette Vanessa 1 , Djocgoue Pierre François 4,5 and Omokolo Ndoumou Denis 4Phytophthora megakarya is an Oomycete which has a negative impact on Cameroon cocoa production. An assessment of the level of virulence of different isolates of P. megakarya in mono or coinfection ...The aim of this work was to evaluate the effect of the soil amendment with bio-oyster shell on the stimulation of the cocoa plant defense systems against P. megakarya in the nursery. For this purpose, the potential of bio-oyster shell to stimulate cocoa plant defense mechanisms was evaluated by soil amendment at 1% W/W under greenhouse conditions.(From Brasier and Griffin, 1979).P. megakarya is a member of Group II of Phytophthora, as defined by Stamps et al. (1990).It produces caducous papillate sporangia, is heterothallic and antheridia are amphigynous.Sporangia are limoniform, obpyriform or ellipsoid with rounded bases, varying from 20-60 x 13-41 µm, with a length-breadth ratio of 1.2-1.6, and are formed in a sympodium.Phytophthora megakarya was frequently isolated from all the three sources of canker infections, indicating P. megakarya readily causes stem canker on cocoa. These results emphasise the importance ...Phytophthora é um género de protistas que engloba algumas espécies particularmente nocivas para a agricultura e silvicultura, responsáveis por várias doenças em plantas, vulgarmente associadas ao termo "podridão". O termo em latim refere-se, aliás, a esta característica ao aliar o termo grego phyton com phthora . Por vezes, tudo ao que parece, por engano, é frequente encontrar a ...In African cacao-producing countries, control of cacao black pod disease caused by Phytophthora megakarya is a priority. Introducing biological control agents as part of a P. megakarya control ...

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An oil-based formulation of T. asperellum PR11 reduced consistently the cacao black-pod-rot (Phytophthora megakarya) under field conditions, showing no significant differences respect to fungicide treatments (Mbarga et al. 2020). Detergents such as Triton X-100 favor the adherence of conidia to infection sites, reducing the growth of …Phytophthora megakarya —one of the cocoa black pod disease species, is invasive and probably responsible for the greatest cocoa crop loss in Africa Phytophthora multivora …Phytophthora megakarya infection. In order to analyse gene expression in response to P. megakarya inoculations of resistant and susceptible cocoa clones, a time course was conducted from 2 to 96 hpi. To verify the success of infection in plant tissues, half-leaves were conserved in a room culture for 6 days and fungal progression on the cocoa ...De acuerdo con [43], la aspersión de ácido fosfónico (H 3 PO 3 40 %) proporcionó un control de P. megakarya equivalente al de la recomendación estándar para el control de la ppm en Ghana ...For example, the species of Phytophthora fungus (Phytophthora palmivora, Phytophthora megakarya, and Phytophthora capsici) cause black rod/pod rot, which leads to a 20–30% loss in yield and 10% mortality …Phytophthora megakarya Taxonomy ID: 4795 (for references in articles please use NCBI:txid4795) current name Phytophthora megakarya type material of Phytophthora …Phytophthora megakarya was frequently isolated from all the three sources of canker infections, indicating P. megakarya readily causes stem canker on cocoa. These results emphasise the importance ...Phytophthora megakarya thrives in very humid climates. Although soil texture plays a central role in the epidemiology of some Phytophthora species (Corcobado et al., 2013), there is a dearth of infor-Abstract Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon. Field experiments were carried out over two successive years in two smallholders' plots of cocoa trees, in order to assess the impact of.Research on resistance to black pod caused by Phytophthora megakarya has been carried out in Cameroon for 40 years. It has yielded a significant database which is currently being exploited for the modelling of disease resistance levels of the major clones selected as candidate parents for the creation of new resistant and consequently more productive cocoa varieties. ….

1. Introduction. Black pod disease, caused by Phytophthora megakarya, is one of the major diseases of cocoa that small-scale farmers are facing in West and Central Africa. In Cameroon, severe economic losses in cocoa production, which ranged from 30% to 80% were caused by this disease in all cocoa-growing regions where no proper control measures were applied [1], [2], [3].inoculum of Phytophthora megakarya (causal agent of cacao black pod rot disease) upon establishment in 2006 were monitored for pres-ence of disease on a weekly basis from 2009 to 2016. Ripley's K(r) function, join count statistics, and Fisher's Exact test were used to analyze spatial and temporal disease dynamics. Disease distributionTitle / Subtitle: Phytophthora megakarya and P. palmivora on Theobroma cacao: Aspects of virulence and the effects of temperature on growth and resistance to fungicides Subject description: This thesis investigates the dynamics of black pod disease of cocoa caused by Phytophthora megakarya and P. palmivora species in Ghana.INTRODUCTION Phytophthora megakarya, causing cacao black pod disease in West and Central Africa is the most virulent of the Phytophthora species reported on cacao (Theobroma cacao) (Cilas and Despereaux, 2004, Ali et al., 2016). In Cameroon, P. megakarya is a major production constraint and losses can easily reach 80-90% when no control measures are taken (Nyassé, 1997, Ndoumbè Nkeng, 2002).In most parts of the world where Theobroma cacao is grown, Phytophthora palmivora is the major concern for causing black pod rot (BPR).Phytophthora megakarya, on the other hand, occurs only in Africa, but represents a major threat to cacao production, the countries of West Africa being the largest producers of cacao in the world.Since cacao did not originate in Africa, P. megakarya obviously ...Feb 2, 2022 · Phytophthora megakarya isolate used in this study was obtained from the microorganism bank of the Laboratory of Phytoprotection and Plant Valorization (LPPV) of the Biotechnology Centre of the University of Yaoundé 1, Cameroon. Zoospore suspensions of P. megakarya isolate PM5 were obtained as described previously . P. megakarya is heterothallic with amphigynous antheridia and distinctly pyriform oogonia. The caducous sporangia are papillate, varying in shape from limoniform, obpyriform, and ellipsoid. Terminal chlamydospores have an average diameter of 30 µm. P. megakarya chlamydospore (left) and oogonium (right) View more images... Genetics: Pod rot, caused by several species belonging to the genus Phytophthora, is the main cause of cocoa harvest losses worldwide. Among the methods making up integrated disease management (IDM), the creation of resistant cultivars has been identified as a priority in cocoa breeding research programmes. To that end, various experiments have enhanced … Phytophthora megakarya, Phytophthora megakarya is the most aggressive of the Phytophthora spp. attacking cocoa and poses a major threat to cocoa production in West and Central Africa (Akrofi et al. 2015). In Cameroon ..., Phytophthora megakarya Taxonomy ID: 4795 (for references in articles please use NCBI:txid4795) current name. Phytophthora megakarya. type material of Phytophthora megakarya: ATCC:42100, CBS:238.83, IMI:202077. NCBI BLAST name: downy mildews Rank: species Genetic code: Translation table 1 (Standard), Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon.Field experiments were carried out over two successive years in two smallholders’ plots of cocoa trees, in order to assess the impact of diseased pod removal (phytosanitary pod removal) on disease progress, total production and final harvest., Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes signifi-cant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The global and highly damaging P. palmivora attacks all parts of the cocoa, Background: Phytophthora megakarya is an invasive pathogen endemic to Central and West Africa. This species causes the most devastating form of black pod disease. Despite the deleterious impacts ..., Introduction. Two species of Phytophthora, P. palmivora and P. megakarya are the main causal pathogens of black pod disease of cocoa in West Africa.P. palmivora has been reported on a large number of host plants. Ashby (1929) described P. palmivora as an omnivorous tropical fungal pathogen of world-wide distribution, existing as a number of morphologically and sometimes pathologically ..., Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa losses in Cameroon.A few studies have focused on describing black pod epidemics in cocoa yet numerous questions remain. Here, an epidemiological model describing the temporal evolution of cocoa black pod, taking into account the development stages of pods, is developed and studied., The negative control using sterile distilled water showed no inhibitory effect on Phytophthora megakarya while 41.00 mm zone of clearance was observed in the positive control test using Metalaxyl ..., The results showed that the colonies growth of P. megakarya 6 days after incubation in V8 media 0,4%, 0,6%, 0,8% more depressed than growth on the V8 without chitosan media.  Keywords ..., The results of the molecular analysis showed the presence of Phytophthora megakarya at 79% against 21% for Phytophthora palmivora. The results of the student t-test showed that this prevalence of black pod is related to the lack of plot maintenance (P=0.036˂0.05) and high leaf coverage of cocoa trees (P=0.003˂0.05)., Abstract Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon. Field experiments were carried out over two successive years in two smallholders' plots of cocoa trees, in order to assess the impact of diseased pod removal (phytosanitary pod removal) on disease progress, total production and final harvest., Phytophthora megakarya is restricted to Cameroon, Nigeria, Togo, and Ghana, causing about 10 percent crop loss. Phytophthora capsici parasitizes cocoa in Central and South America. It is the predominant cause of pod rot in Brazil where it is less aggressive than Phytophthora palmivora. Phytophthora citrophthora also attacks, After 36 months of sampling and baiting, P. megakarya was isolated from the roots of four out of 34 shade tree species examined. The host trees were Funtumia elastica (Apocynaceae), Sterculia ..., Mar 2, 2015 · Phytophthora megakarya Brasier & Griffin, is one of the Oomycete pathogens reported on Theobroma cacao,and it is the most virulent of the Phytophthora species that causes black pod disease. Phytophthora megakarya was first reported as the causal agent of black pod disease in 1979 after the reclassification of Phytophthora species recovered from ... , The oomycete genus Phytophthora includes devastating plant pathogens that are found in almost all ecosystems. We sequenced the genomes of two quarantined Phytophthora species–P. fragariae and P. rubi.Comparing these Phytophthora species and related genera allowed reconstruction of the phylogenetic relationships within the …, May 1, 2004 · Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon.Field experiments were carried out over two successive years in two smallholders’ plots of cocoa trees, in order to assess the impact of diseased pod removal (phytosanitary pod removal) on disease progress, total production and final harvest. , spesies Phytophthora telah berhasil diisolasi dari tanaman kakao sakit di seluruh dunia, ... yaitu P. palmivora, P. megakarya dan P citropthora yang menimbulkan kerugian paling besar pada kakao ..., Enter the email address you signed up with and we'll email you a reset link., In Ghana, Phytophthora palmivora and P. megakarya are the main causes of black pod disease of cocoa (Dakwa, 1988;Luterbacher and Akrofi, 1993; Opoku et al, 1999). Research has shown that the ..., 2019年8月12日 ... Phytophthora megakarya Brasier & M.J. Griffin 1979. This oomycete is found in western Africa where it is an important and specialized ..., Phytophthora megakarya was more aggressive than P. palmivora on attached SCA-6 pods, causing expanding necrotic lesions with or without wounding. Phytophthora megakarya is predominant in the Volta region of Ghana and it remains to be seen whether it can displace P. palmivora from cacao plantations of Ghana as it has in Nigeria and Cameroon., 2019年8月12日 ... Phytophthora megakarya Brasier & M.J. Griffin 1979. This oomycete is found in western Africa where it is an important and specialized ..., In Cameroon, Phytophthora megakarya is the causal agent of black pod rot of cacao (Theobroma cacao L). Primary inoculum of P. megakarya is located in the soil. With the onset of the rainy season ..., Depending on the site, PR11 was able to reduce percentage pod rot between 13 and 34% whereas the combination of PR11 and Kocide reduced pod rot by 48% in one instant, demonstrating the potential for integrated control using fungicide and fungicide-BCA combinations. Control of Phytophthora megakarya, the causal agent of cocoa black pod in Cameroon is commonly obtained by fungicide spraying of ..., Pod rot caused by the oomycete Phytophthora mega- karya is t he most deva stat ing d iseas e of t he co coa plant, claiming up to 30 % of the world cocoa harvest, , Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) cause black pod rot of Theobroma cacao L. (cacao). Of these two clade 4 species, Pmeg is more virulent and is displacing Ppal in ..., Phosphonic Acid: an Alternative Approach to the Control of Black Pod Disease of Cocoa Caused by Phytophthora Megakarya; Phytophthora Palmivora Establishes Tissue-Specific Intracellular Infection Structures in the Earliest Divergent Land Plant Lineage; Effect of Storage on the Antimicrobial Potencies of Some Botanicals Against Phytophthora ..., Phytophthora megakarya and P. palmivora are oomycete pathogens that cause black pod rot of cacao (Theobroma cacao), the most economically important disease on cacao globally. While P. palmivora is a cosmopolitan pathogen, P. megakarya , which is more aggressive on cacao than P. palmivora , has been reported only in West and Central Africa where ..., The aim of this work was to evaluate the effect of the soil amendment with bio-oyster shell on the stimulation of the cocoa plant defense systems against P. megakarya in the nursery. For this purpose, the potential of bio-oyster shell to stimulate cocoa plant defense mechanisms was evaluated by soil amendment at 1% W/W under greenhouse conditions., Phytophthora megakarya were investigated. Root colo-nization by AM fungi is between 50 and 70% 18 weeks after planting. Tested AM fungi significantly increased all the plant growth parameters ..., Jul 31, 2022 · Phytophthora megakarya is a plant pathogen that causes black pod disease in cocoa trees in West and Central Africa. This pathogen can cause detrimental loss of yield in the economically important cocoa industry. It can damage any part of the tree, causing a wide range in the reduction of yield. A mi , Cacao black pod rot (BPR), caused by Phytophthora megakarya is the most important cacao disease in Cameroon. Biocontrol of this disease using an oil-based formulation of Trichoderma asperellum PR11 provided more consistent and long-lasting protection of cacao pods under laboratory and experimental plot conditions. The …