Phytophthora megakarya
Biological control of Cocao black pod disease (Phytophthora megakarya) with Trichoderma species. 15 th International Cocoa Research Conference (ICRC) held in Costa Rica between 14 th and 21 st.An aqueous leaf extract of Talinum triangulare was screened for the presence of bioactive molecules, using gas chromatography coupled with pulse and flame ionization detectors. It had high carotenoids; moderate benzoic acid derivatives, hydroxycinnamates and flavonoids; and low terpenes, alkaloids, phytosterols, allicins, glycosides, saponins, and lignans contents.Phytophthora megakarya et Phytophthora palmivora. Ces Oomycètes sont responsables d'une perte de production qui s'élève à plus de 80 %. Afin de mieux lutter contre la maladie, il est
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Phytophthora megakarya isolates were uniformly virulent in an assay using susceptible cacao pod husks inoculated with zoospores, while the P. palmivora isolates showed greater divergence in virulence. The virulence of P. megakarya was associated with earlier production of sporangia and an accelerated induction of necrosis. While zoos-Phytophthora megakarya, Thevetia peruviana, extract, biocontrol, black pod disease. INTRODUCTION . The protection of plants against crop diseases and . pests is a key factor in the increase of cr op .Many Phytophthora species have a soil borne phase in their natural life cycles even though disease expression often occurs on aerial plant parts. In Cameroon, black pod rot of cacao (Theobroma cacao L.), is caused by P. megakarya. Primary inoculum ofNov 4, 2021 · 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 of cacao (Bridgemohan and Mohammed, 2019). Section snippets Resistance measured by the rotten pod rate in the field. The data used came from several mating designs set up in zones affected by the disease in producing countries: Cameroon, primarily with P. megakarya, Togo with P. megakarya and P. palmivora, and Ivory Coast, where P. palmivora is predominant, but which is threatened by the spread of P. megakarya in the east of the ...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.Analysis of expressed sequence tags (ESTs) from cocoa (Theobroma cacao L) upon infection with Phytophthora megakaryaAbstract. Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) are closely related species causing cacao black pod rot. Although Ppal is a …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.(A) Black pod rot symptoms by P. megakarya and P. palmivora. (B) Approximate geographical distribution of P. megakarya (yellow area) and P. palmivora (blue area). (C) Clock-calibrated phylogenetic tree with estimated times of divergence and WGD duplication events in P. palmivora and P. megakarya in million years ago, with numbers of families expanded and contracted across multiple Phytophtora ...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 strategy is highly desirable, especially in a perspective of pesticide reduction.Trichoderma species are among the most used biological control agents. In Cameroon, Trichoderma asperellum formulated in ...Dec 11, 2015 · 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. Phytophthora pod rot (Ppr) disease caused by Phytophthora megakarya is the major constraint to cocoa production in Cameroon. The development of resistant varieties requires the use of effective ...Among 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.
Although P. megakarya only exists in Africa, the species Phytophthora palmivora and Phytophthora capsici are responsible for the disease in South America. The search for effective control methods was stepped up in 1988, when P. megakarya arrived in Ivory Coast, the world's leading cocoa-producing country. Genetic control is a promising solution ...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. 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 cocoa in Brazil.Black pod, caused by Phytophthora spp. is one of the most important diseases of cacao occurring worldwide. Losses due to black pod caused by P. palmivora are still moderate in Côte d'Ivoire but P. megakarya causes high losses in Ghana and other Central African countries. Variation in field attack has been observed between cacao genotypes, but evaluation of pod losses is unsuitable for ...
Cocoa (Theobroma cacao L.) is a major foreign revenue earner for Ghana.Black pod disease caused by P. palmivora and P. megakarya, causes economic yield loss in cocoa production in Ghana (Adomako 2007; Opoku et al. 2000).In 2012 alone, it is estimated that Ghana lost revenue of about US$ 3.9 million (25% of annual crop) to …35 strategy appears to be an effective approach to control black pod for newly established cacao plantations. 36. Keywords: Phytophthora megakarya, primary ...…
Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. Phytophthora species produce a protein that has a similar sequence . Possible cause: Phytophthora megakarya —one of the cocoa black pod disease species, is invasive and prob.
Phytophthora (Fy-TOFF-thor-uh) species make up a group of microorganisms that are important plant pathogens. The name Phytophthora derives from Greek and literally means “plant destroyer.” Phytophthora species resemble fungi but are not. While they are most closely related to aquatic organisms, such as brown algae and diatoms, they can also exist on land. However, Phytophthora organisms ...Chitosan and chitin sources have emerged as promising groups of biological substances that can induce plant growth and resistance to diseases. This study is aimed at investigating the potential effect of chitosan and snail shell to promote cocoa growth and induce resistance against Phytophthora megakarya. The results showed that treatment of cocoa seeds with chitosan at 1.5 to 2.0% and snail ...
Newly encountered pathogens in West Africa (Cacao swollen shoot virus and Phytophthora megakarya) and Asia [Ceratobasidium (aka Oncobasidium) theobromae] are serious problems in those areas, as are other fungi and stramenopiles with wider geographic distributions. The ranges of the major pathogens and the impacts and losses that result …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 .
Phytophthora megakarya and Phytophthora palmivora, c Introduction. Phytophthora megakarya is the most aggressive fungal pathogen on Theobroma cacao L. and poses a major threat to cocoa production in West and Central Africa. It was originally identified in Nigeria in 1979 (Brasier et al., 1981), reported in Togo in 1982 (Djiekpor et al., 1982), and was subsequently reported in Ghana in 1985 (Dakwa, 1987). Phytophthora megakarya only occurs in countries in West and Ce54 the black pod disease caused by Phyto Phytophthora megakarya obtained from a 7-day-old potato dextrose agar (PDA) culture medium and incubated at 25-26 °C in the totally dark and humid chamber. Control leaves were inoculated with sterileBlack 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. Phytophthora megakarya Taxonomy ID: 4795 (for references in articles Phytophthora megakarya and Phytophthora palmivora are considered the most important for cacao cultivation in Central and West Africa and most studies are related to them (Guest 2007; Adomako 2007 ...The only economically important host of Phytophthora megakarya Brasier & Griffin is Theobroma cacao. The pathogen is one of several Phytophthora species causing black pod disease of cacao. Isolates of P. megakarya were grouped taxonomically with P. palmivora isolates until 1979, when it was recognized as a new species (Brasier and Griffin, 1979). The cocoa black pod disease is caused by a fungus Phytophthora sp, whStudying spatial and temporal plant diseaseDefense gene polymorphisms were identified which could contri P. megakarya is primarily known for the damage it causes to the cacao pod, but it is known to subsist on roots (Gregory et al., 1984) and can cause dieback of seedlings (Bowers et al., 2001). Since all Phytophthora spp. causing black pod disease of cacao in Africa were classified as P. palmivora prior to 1979 (Brasier and Griffin, 1979), it is ... For example, the species of Phytophthora fungus (Phytophtho Physiological studies were made of six isolates of Phytophthora from cocoa, three of the A2 mating type of P. palmivora (71, 78, and 29) and three of the A1 mating type of the recently described P. megakarya (9A, 75, and 10B). Many of these studies revealed a clear differentiation between the two species. In all experiments the growth rate of the isolates of P. palmivora was higher than that ...IDphy was developed to facilitate accurate and efficient identification of Phytophthora to species, using type specimens from the original descriptions for reference wherever possible. IDphy emphasizes species of high economic impact and species of regulatory concern for the U.S. IDphy includes molecular and morphological tools to aid in ... inoculum of Phytophthora megakarya (causa[Phytophthora megakarya—one of the cocoa black pod Although several Phytophthora species can infect cacao plants Diversity of Phytophthora megakarya in Central and West Africa revealed by isozyme and RAPD markersPhytophthora megakarya in nurseries. The results showed that heat-treated oyster shells powder at 1% (w/w) soil amendment significantly increased plant height, leaf number, leaf area, dry shoot and root weight more than chemical fungicide and control treatment after twelve weeks of growth. The