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Abstract
This fifth edition of the classic textbook in plant pathology outlines how to recognize, treat, and prevent plant diseases. It provides extensice coverage of abiotic, fungal, viral, bacterial,nematode and other plant diseases and their associated epidemiology. It also covers the genetics of resistance and modern management on plant disease.Plant Pathology, 5th Edition, is the most comprehensive resource and textbook that professionals, faculty and students can consult for well-organized, essential information. This thoroughly revised edition is 45% larger, covering new discoveries and developments in plant pathology and enhanced by hundreds of new color photographs and illustrations.
... Sorghum is a rich source of phytochemicals like tannins, phenolic acids, anthocyanin, phytosterols, and poliosanols, according to Smith and Frederiksen (2000). According to Agrios (2005), plants can exhibit true, racespecific, cultivar-specific, or gene for resistance to some pathogens by belonging to taxonomic groups that fall outside of their host range, by having resistance genes (R genes) directed against the pathogen's avirulence genes, or by escaping or tolerating infection by these pathogens, among other explanations (apparent resistance). However, all plants have some level of resistance that may not be specific to any pathogen in particular, but is usually present; Although this resistance is occasionally referred to as partial, race-neutral, general, quantitative, polygenic, adult-plant, field, or durable resistance, historically, the term "horizontal resistance" has been used most frequently (Agrios, 2005). ...
... According to Agrios (2005), plants can exhibit true, racespecific, cultivar-specific, or gene for resistance to some pathogens by belonging to taxonomic groups that fall outside of their host range, by having resistance genes (R genes) directed against the pathogen's avirulence genes, or by escaping or tolerating infection by these pathogens, among other explanations (apparent resistance). However, all plants have some level of resistance that may not be specific to any pathogen in particular, but is usually present; Although this resistance is occasionally referred to as partial, race-neutral, general, quantitative, polygenic, adult-plant, field, or durable resistance, historically, the term "horizontal resistance" has been used most frequently (Agrios, 2005). Nevertheless, a number of biotic factors, such as the fungi that cause anthracnose and grain mold, restrict the productivity and profitability of the sorghum crop. ...
... Among the plant pathogens, soil borne dwellers plays an important role in the damage of plants, resulting in the significant yield loss. Plant diseases are controlled using different options including fungicides, cultural practices such as weed and residue management, planting disease free seeds, crop rotation and planting of resistant varieties. Among the control measures, the use of resistant varieties is the most economical as well as its advantage of being ecofriendly (Agrios, 2005). This raised the need to screen different cultivars of some Sorghum germplasm for horizontal resistance. ...
Soil borne pathogens appears to be one of the most devastating groups affecting S. bicolor
causing wide range of pre-harvest and post-harvest diseases, plant diseases are commonly
managed through different strategies, the use of resistant varieties found to be more
economical and ecofriendly. This poses the need to screen different varieties of S. bicolor for
horizontal resistance of some fungal species commonly found in the soil. Plate technique
was used to isolate soil fungi and morphological identification was through macro and
microscopy. Koch’s postulate was followed in the assessment of pathogenicity of the
identified organisms on the three sorghum germplasms (Yelai, Kaura and Warwarbashi). The
isolated fungal species were found to be Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer,
Mucor spp and penicillium spp. Pathogens with highest occurrence observed was A. niger , R.
stolonifer and Penicillium spp with 30, 25 and 20% occurrence respectively. Thus, all the three
cultivars of S. bicolor screened were very susceptible to the tested pathogens, with A. niger
and R. stolonifer found to be highly virulent. It was concluded that, all the varieties showed a
continuous minute or absence of horizontal resistance against the isolated pathogens which
could be responsible for post-harvest diseases in Sorghum germplasm
... It also causes the dumping of disease and is easily recognized by the presence of white mycelium on the infected plant parts and in subsequent attacks will form sclerotia. Globally, this disease affects plants at all stages of growth, including seeds, and mature plants (Agrios, 2005). ...
... This fungus has a wide host range, which makes it difficult to control (Semangun, 2004), and can survive in the soil in the form of sclerotia for several years (Punja, 1985). According to Agrios (2005), sclerotia can last for 2-3 years depending on the availability of organic matter. ...
Botanical fungicides are fungicides derived from plants that produce chemical compounds that potentially inhibit microbial growth. These fungicides are safe because to its not harmful to humans and the environment. In the present study, the plant materials used often compete with plant materials used for food and medicine such as galangal rhizomes and betel leaves. Therefore, it is necessary to explore materials derived from plants that have not been widely utilized. So the research was conducted to determine the effect of leaf extracts from several plants on the growth of Sclerotium rolfsii Sacc. the fungus that causes wilt disease in plants and determines the level of antifungal activity. This research was conducted using a completely randomized design (CRD). The leaf extracts used were from the plants Muntingia calabura, Terminalia cattapa, Syzygium oleina, Morinda citrifolia, Dimocarpus longan, and Artocarpus altilis with concentrations of 10%, 20%, 30%, 40%, and 0% as control. The data obtained were analyzed using variance analysis (ANOVA) with Duncan's New Multiple Range Test (DNMRT). The results showed that all treatments used could inhibit the growth of S. rolfsii Sacc because they were significantly different from the control. It was determined that antifungal activity in leaf extracts of M. calabura, T. cattapa, S. oleina, and D. longan was very strong, and also A. altilis had a strong antifungal activity, while M. citifolia had a moderate antifungal activity.
... This indicates at the cotyledon growth stage of the Ethiopian mustard is able to resist the white rust. The results of the present study conform to those reported earlier by Shek et al., (2017) and the concept was related to Agrios, (2005) as the resistance to disease increased as the plant reached maturity. But, we didn't find a correlation between J. Bio.Innov12(2), pp: 378-403 2023 |ISSN 2277-8330 (Electronic) Selvaraj et al., ...
... The strong correlation between leaf spot and white rust on mustard resulted in synergistic effects. This result was related to the time response for more than one disease, as both the plant and its efficacy can be reduced during this time (Agrios, 2005). ...
Ethiopian mustard (Brassica carinata A. Braun) is among the oldest oil crops widely cultivated in Ethiopia. White rust (Albugo candida (Pers. ex. Hook) O. Kuntze) is one of the important major diseases of Ethiopian mustard in the highland areas of West Shewa, Ethiopia which is responsible for reducing the yield losses due to white rust on Ethiopian mustards estimated to be 8-60 %. Therefore, the aim of this study was carried out to assess the intensity of white rust and the reactions of Ethiopian mustard genotypes to white rust for their host resistance in West Shewa, during the main cropping season of 2021, in four districts viz. Dendi, Welmera, Jeldu, and Dire Incini of West Shewa zone, Ethiopia. The incidence and severity was assessed and recorded once during the survey on each farmer's field and the suspected disease symptoms of white rust on Ethiopian mustard. The incidence of white rust varied from 40.8-100% and the severity index ranged from 4-50.13%. The results were revealed that the white rust was assessed in all the study fields in Dendi district, with prevalence of 100% and in Welmera, Jeldu, and Dire Incini districts, with a prevalence of 93.3, 86.6, and 80%, respectively. The white rust intensity among different agronomic practices, at different growth stages, cropping systems and the effects of weeding and plowing frequency showed the highest white rust incidence and severity was recorded in true leaves and at pod growth stages in which both were not significantly different from each other but significantly different from cotyledons. The maximum level of white rust incidence and severity was recorded at a high altitude level of 2413 m.a.s.l. in the study areas. The field experiment was conducted at Holleta Agricultural Research Centre, to evaluate 20 Ethiopian mustard genotypes for host resistance against white rust during the main cropping season of 2021/22. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications of each treatment. The results under field conditions revealed that among 20 genotypes tested, two genotypes (S-67xHoletta-1-9/2/18/2/37/4/1 and Yellow dodola) were highly resistant, followed by 3 genotypes (Y.D.xBAR-1029/79-436/2002/9/2/15/1/28/1, S-67xHoletta-1-9/2/18/2/24/2, and S-67xHoletta-1-9/2/18/2/37/4) were resistant, five genotypes (S-67xHoletta-1-9/2/18/2/45/3, Y.D.xBAR-1030/79-436/2001/6/2/11/1/18/3, Y.D.xBAR1030/79-436/2001/6/2/11/1/18/2, S-67xHoletta-1-9/2/18/2/37/3 and S-67xHoletta-1-9/2/18/2/37/3) 2023, March Edition |www.jbino.com | Innovative Association 2 J.Bio.Innov12(2), pp: 378-403 2023 |ISSN 2277-8330 (Electronic) Selvaraj et al., were moderately resistant, while the other 10 genotypes were susceptible. The least AUDPC value was recorded from S-67xHoletta-1-7/1/13/2/26/2. Overall, the present study concluded that S-67xHoletta-1-9/2/18/2/37/4/1 and Yellow dodola were highly resistant, which can be easily adopted by the farmers to control white rust in their cultivated fields. Therefore, the current study suggests that the prevalence of the pathogen and the reactions of tested lines that rescuer further evaluation of resistance across the locations.
... There were some genera in R that were mycoparasitic (i.e. parasitize other fungi) such as Clavispora (Pereyra et al. 2020) and Pichia (Agrios 2005), as well as entomopathogenic (i.e. parasitize insects) such as Arthrobotrys (Barron 2004) . ...
... Though Curtobacterium was not detected in R, Xanthomonas, as well as the related phytopathogen Ralstonia, were found in common in Orobanche and Rafflesia seeds sampled here, but not in any of the Tetrastigma samples. It is thus tempting to speculate that holoparasites may be exploiting the cell-wall degrading enzymes secreted by these phytopathogens (Agrios 2005) to infiltrate host tissue. ...
Rafflesia is an endangered endophytic holoparasitic plant that lives the majority of its life inside the tissues of its sole plant host, Tetrastigma. Rafflesia floral buds emerge to produce the world’s largest single flower. Like other plants, holoparasites harbor a diverse microbiome, the role(s) of which has remained largely unstudied. We characterized the bacterial microbiome of seeds of Rafflesia speciosa and cuttings of its host. We found evidence that R. speciosa seed has similar bacterial profiles to its infected host, which suggests that seeds sequester certain host bacteria, as well as acquire unique bacterial taxa from biotic associates of the fruit. We did not find evidence of mycorrhizal taxa in the microbiome. This is the first study of the microbial endophytes associated with any Rafflesia species and its host, a tripartite holobiont, and provides insights on its cryptic microbial partners. We discuss how this may aid horticultural propagation of Rafflesia.
... Fusarium also produces three types of asexual conidia in the soil. Macroconidia, consisting of 3-5 cells gradually pointed and curved ends and Microconidia which may be bicellular or unicellular, in addition to chlamydospores, which are single to fivecelled spores and have a thick wall that may be spherical or elongated shape [Agrios (2005)]. F. oxysporum strains are ubiquitous soil inhabitants that have the ability to exist as saprophytes and degrade lignin and complex carbohydrates associated with soil debris. ...
... Fig. 2 shows that the effect of Matricaria chmomilla extract inhibited A. terreus, which amounted to 6.9 cm. The percentage of inhibition of F. oxysporuim amounted to 4 cm and through these results conclude that the difference in the types of fungi leads to the difference in the effect of the extract from one fungus to another [Agrios (2005)]. Fig. 3 and Image 1 present of the effect of Rhus angustifolia extract on inhibiting the growth of F. oxysporum, which amounted to 3.9 cm, as well as the effect of extract in inhibiting the growth of A. terreus, which amounted to 5.7 cm. ...
... However, the overall functional role of oomycetes in the forest soil ecosystems is still poor-studied, and only few genera have been extensively investigated, such as Pythium and Phytophthora. The soilborne oomycete genus Pythium is mainly composed by saprophytic and opportunistic species, turning between different trophic strategies according to the availability of carbon sources (Kramer et al., 2016), even to the point of acting as damping off agents of forest seedlings (Agrios, 2005;Beakes and Thines, 2016). On the contrary, the genus Phytophthora has attracted significantly more interest and some of its most aggressive species were exhaustively studied in the past (Burgess et al., 2017). ...
... Besides the high importance of oomycete communities in agroecosystems where their presence and influence are of a primary concern (Agrios, 2005), their landscape-scale occurrence in natural habitats is still little known. Despite a few case studies have revealed that oomycete communities are correlated with the environmental factors such as altitude, geomorphology and soil structure (Sapp et al., 2019), limiting factors and dispersal distance are poor understood factors in oomycete communities, except for few aggressive pathogenic species (Gómez-Aparicio et al., 2012;Cardillo et al., 2018;Sánchez-Cuesta et al., 2022). ...
Understanding the effects of windstorm disturbances on soil communities is of pivotal importance. Oomycete communities host some species of plant pathogens, which might affect the forest regeneration after the disturbance. Here, we sampled a large area to compare three habitats (e.g., windfall, old clearings, and undisturbed spruce forest) along a gradient of elevation and slope. We used an eDNA metabarcoding approach targeting the rps10 gene. Our results showed that both wind disturbance and underlying topography can influence the richness of oomycetes. Higher richness of oomycetes was found in disturbed sites and high steepness. We did not find differences in community composition among the different habitat types at the landscape scale. However, we found significant differences among drainage basins at larger spatial scale. Our work contributed to the understanding of the oomycete communities in Norway spruce forests affected by wind disturbance.
... Penyakit hawar daun dapat menyerang daun dan batang tanaman kentang pada masa pertumbuhan tanaman (Agrios, 2005;Lal et al., 2018). Selain itu, patogen juga menyerang umbi kentang di lapangan atau penyimpanan. ...
... Selain itu, patogen juga menyerang umbi kentang di lapangan atau penyimpanan. Penyakit ini dapat merusak seluruh areal tanam dalam satu atau dua minggu pada saat suhu rendah dan kelembapan tinggi (Agrios, 2005). Gejalanya berupa bercak-bercak basah berwarna hijau pucat atau busuk berwarna coklat kehitaman pada daun dan batang tanaman, bahkan sampai ke umbi. ...
Produksi kentang di Indonesia berkontribusi + 0,3% dari total produksi dunia sebesar + 388.191.000 ton. Kentang merupakan komoditas hortikultura esensial di Indonesia dengan permintaan sekitar 2,82 kg ha-1 kapita-1 pada tahun 2021. Saat ini terjadi defisit ketersediaan kentang yang mencapai 4.845.910 ton yang diperparah dengan terus menurunnya produksi kentang nasional (1.164.738 ton). Penyakit hawar daun (Phytophthora infestans) merupakan salah satu masalah utama penyebab penurunan produksi kentang (kehilangan hasil antara 10-100%). Penyebaran penyakit hawar daun sulit untuk diidentifikasi secara real time, sehingga diperlukan teknologi tepat guna yang dapat memberikan informasi secara cepat dan akurat. Penelitian ini bertujuan untuk melihat bagaimana foto udara (dari UAV) memperkirakan sebaran penyakit hawar daun pada kentang. Foto UAV diubah menjadi indeks NDVI, RDVI, SAVI, SR, ARVI-2, DVI, IPVI, dan GCI. Data pengukuran indeks penyakit hawar daun akan dikorelasikan dan dipilih yang terbaik untuk mendapatkan rumus regresi distribusi spasial penyakit hawar daun. Lokasi penelitian berada di Kecamatan Bumiaji, Kota Batu, Indonesia. Titik pengamatan di lapangan sebanyak 50 titik pengamatan untuk setiap luasan 3 Ha. Hasil penelitian menunjukkan bahwa semua indeks berkorelasi positif (> r tabel 0,34). Korelasi tertinggi pada estimasi model dari indeks NDVI (0,72). Kondisi ini sejalan dengan koefisien regresi (R2) pada NDVI yang mencapai 0,51 dengan persamaan y = 20,779 * (angka indeks NDVI) + 49,146. Analisis t-paired menunjukkan bahwa t hitung pada model (-1,10) ada pada grafik t-tabel (2,16), dan ini menegaskan bahwa rumus tersebut dapat diandalkan untuk digunakan.
... The losses are usually lower in the more developed countries and higher in the developing countries, i.e., countries that need food the most. It has been estimated that of the 36.5% average of total losses, 14.1% are caused by diseases, 10.2% by insects, and 12.2% by weeds (Agrios, 2005). Plant diseases caused by pathogenic microorganisms represent a serious threat to plant productivity, food security, and natural ecosystems. ...
... Among the plant pathogens, around 85% of diseases in plants are caused by fungi. More than 10,000 species out of 100,000 recognized fungal species may cause diseases in plants (Agrios, 2005). Phytopathogenic fungal species can cause enormous losses in quantity and quality of crop yields, and this is a major economic issue in the global agricultural sector. ...
The present study was carried out to detect the proteolytic activity of Bacillus species
isolated from different sources (beef, milk, chicken, egg, and rice). A total of fifty isolated samples were
collected randomly from a public restaurant in Khartoum state, Sudan. Ten samples from each source;
5 were freshly cooked (10 - 30 minutes before sampling) and 5 were raw. The isolation of bacteria has
been carried out perfectly according to the construction of the standards, and identification was done
using primary and secondary biochemical tests. The result revealed that out of 50 samples, 20 were
Bacillus isolates which comprised 40% of the total samples. They were B. circulan 5%, B. cereus 5%,
B. megaterium 10%, B. macerans 10 %, B. licheniformis 5%, B. pamilus 5%, B. subtilis 20%, B.
coagulans 15%, B. laterosporus 5%, and B. amyloliquefaciens 20%. After isolation of Bacillus spp., the
investigation was continued to detect protease production using milk agar medium, the most productive
organism was found to be B. macerans and the lowest one was found to be B. amyloliquefaciens
whereas there was no production by B. circulans. The study concluded that Bacillus species were found
in all food sources, so Bacillus genera consider a major cause of food contamination, as well as cooked
food is considered most contaminated by Bacillus than raw food.
... Mikroorganisme antagonis dapat disebarkan di sekitar perakaran tanaman atau bagian tanaman sebelum maupun setelah terjadi infeksi. Mikroorganisme seperti jamur, bakteri, virus tertentu dapat berperan sebagai agen antagonis (Agrios, 2004). ...
... Agen pengendali hayati atau agen hayati merupakan mikroorganisme yang dapat bermanfaat untuk menekan patogen penyebab penyakit tanaman. Beberapa agen hayati yang telah diketahui dapat dijadikan sebagai biopestisida yaitu dari kelompok bakteri, jamur dan virus (Agrios, 2004 ...
... Abiotic factors such as extreme temperatures, precipitation, wind, and drought further render plants more vulnerable to pests and pathogens. For example, Agrios (2005) positioned temperature and moisture as significant environmental factors that affect the occurrence and development of various infectious plant diseases. With an unprecedented future climate predicted to be characterized by increased warming, even under prescribed climate mitigation scenarios, there is a need to continuously understand how climate change will impact plant-pathogen/pest dynamics. ...
Fall Armyworm (FAW) is among the major pests that destroy important food crops. With origins in the Americas, it was first detected in West Africa in 2016 and has since spread rapidly to other African countries and other continents. Studies have investigated FAW behavior and distribution, however, studies of how climate change may affect FAW suitability have been poorly explored. Reports on how FAW prediction is likely to spread in African countries that lack advanced technologies and practices to prevent the pest could be an approach that enables decision-makers to adapt and take control measures in areas at risk. In this research, we identified the climatic factors that influenced the incidence of FAW pest, and mapped and predicted its suitable habitat in the eastern African region. Findings revealed that five variables had the greatest impact on the performance of the model, among 19 bioclimatic variables. With a contribution of 37.8%, the annual precipitation had the most influence, followed by the annual mean temperature which contributed 13%. FAW potential distribution was also predicted under current climatic conditions, (1970-2000), and for future climate change scenarios, SSP1-2.3, SSP3-7.0, and SSP5-8.5, for the periods 2021-2040 (near term), 2041-2060 (mid-term) and 2061-2080 (long-term). This study showed that in the current climatic conditions, most of the area under study is suitable for FAW incidence and that in the future, this suitable habitat will increase northwards and decline in the southern region. Control and monitoring measures should be adopted to prevent the spread and excess damage of the FAW pest in the eastern Africa region. Studies utilizing different climate models, SSP scenarios, and different periods should be the focus of future research. Understanding 91 | Ntwari et al., 2024 Sustainability and biodiversity conservation 3(1): 90-107 additional non-climatic elements that affect the growth, development, and distribution of FAW also needs more research.
... The constitutive biochemical apparatus includes phenolic compounds, saponins, unsaturated lactones, glycosides, phytotoxins, antimicrobial proteins and peptides. The activated biochemical substances include phytoalexins, ROS and proteins related to pathogenesis (PR), which can also preexist in the plant [130]. In recent decades, phytohormones have stood out in plantpathogen interactions as a biochemical defence. ...
Extreme events of climate change are increasing, such as droughts and heat waves, causing limitations on growth and yield in relevant food crops, as well as threatening global food security. Brassinosteroids (BRs) are natural or synthetic steroids with significant properties that promote plant growth and development. In the current world scenario, research and solutions that can improve plant tolerance to climate change are strategic to ensure food security. The distinctiveness and novelty of this review lie in its comprehensive and detailed approach to the role of BRs in plants under biotic and abiotic stresses. We consolidate information on the action mechanisms on specific organs, providing detailed experimental conclusions of these plant growth regulators, including also commercial products and concentrations tested aiming to mitigate the adverse effects of the stresses. This practical approach highlights the potential of BRs in agriculture and plant protection against stresses. Additionally, our review presents results with plant models and essential food crops, focusing on multidisciplinary approaches and using physiological, biochemical, nutritional, anatomical and agronomic tools to explain the mechanisms of action of brassinosteroids in plants exposed to abiotic and biotic stresses.
... Solar radiation plays a crucial role in agriculture (especially in India) as it directly influences plant growth, development, and productivity. Adequate solar radiation is essential for photosynthesis, which is the process by which plants convert sunlight into energy to fuel their growth (Agrios, 2005;Hatfield & Prueger, 2015;Sinclair & Muchow, 1999). ...
The unprecedented rise of solar energy as a dominant power source is a remarkable feat, considering our historical struggle to establish its widespread adoption. However, the dynamics of solar radiation reaching the Earth's surface are greatly influenced by meteorological conditions such as clouds, aerosols, and wind speed. This study investigates the detailed changes in surface-reaching solar radiation within the subtropical region Pune from 1993 to 2022. By employing analytical methodologies including linear regression, wavelet coherence, and quantitative analysis, our study reveals a compelling and alarming pattern of plummeting solar radiation over Pune (also known as solar dimming). The total drop is ~1.04 Wm − 2 year − 1 (0.21 % year − 1), with a more steep decline registered from 2018 to 2022, providing an astonishing rate of ~6.01 Wm − 2 year − 1 (1.21 % year − 1). Moreover, wavelet coherence transform revealed an antiphase coherence between solar radiation and both clouds and aerosols, suggesting their substantial influence over a longer timeframe. Extensive analysis utilizing observational data is conducted to find the contributing elements to the significant decline during 2018 to June 2022. Analysis of solar radiation statistics showed that clouds led to a substantial reduction of ~30.18 % compared to conditions with clear-skies. Similarly, the aerosols have a comparable effect, reducing radiation by ~17.75 % compared to days characterized by low or negligible aerosol loading for the same period. Furthermore, a through statistical analysis investigates a notable anticorrelation (ρ = − 0.64) between wind speed and solar radiation. These findings underscore the imperative of incorporating climatic variables while studying solar dimming trends and devising sustainable renewable energy strategies to ensure the long-term viability of solar energy source.
... loss of wilted plants approximately60 to 70% and have yellowed leaves (R.Singh et al., 2015). Irrigation water and farm equipment's that are contaminated with FOL are the main source of spread of this pathogen on short distance and at long distance this pathogen that cause wilt disease on tomato plant can spread through contaminated soil, infected transplant etc., (G.Agrios, 2005a).WhenFOL infect a region then that region contaminated with FOL and this fungus remains there forever (Animashaun, Popoola, Enikuomehin, Aiyelaagbe, & Imonmion, 2017; Prihatna, Barbetti, & Barker, 2018). Management The pathogen of fusarium wilt of tomato can survive in the soil in the form of chlamydospore and in infected plant debris in the form of mycelium for a long period of time so that's why the control of this pathogen infection in the field is not easy(Haware, Nene, & Natarajan, 1996). ...
Tomato is famous and vital vegetable in the world and it is very beneficial to human health. Fungal pathogen reduce the production of tomato. In Pakistan, the main reason of reduction in production of tomato crop is due to diseases. Fusarium oxysporum f.sp. lycopersici is fungal pathogen that cause vascular wilt disease in tomato. And this pathogen is from family Ascomycota and hypocreales order. 10 to 50% and 10 to 90% tomato crop losses in the world and in Pakistan warm regions respectively. Pathogen is saprophytic in nature and is soil borne and can survive in soil for many years. Young leaves show symptoms and growth is stunted and death occur. Sindh and Northern areas of Pakistan show disease with variation in disease incidence. Acidic soil and 25 to 28°C temperature favor infection. FOL enter in root epidermis and spread in tissues of vascular system. Furthermore, clogging in vessel show wilting symptoms. Chlamydospore is dormant and is present in soil even host is not present. Contaminated soil and farm equipment’s, infected transplant and irrigation water are main source of spread of this pathogen. In Pakistan that disease is managed by integrated practices such as use of resistant varieties, bio-control agents and systemic induced or acquired resistance. Use of resistant varieties and crop rotation is best way to manage this disease. Soil pH should be raised to control this disease and use of certified seed can also control this disease. Fol can control by SAR (Systemic Acquired Resistance), induced resistance, Plant resistance protein, foliar spray and Seed treatment. Fumonisin produced by pathogenic strains that infect tomato crops have mycotoxins ability.
... Total 1g of each sample was placed in separate test tubes containing 9ml peptone water. The test tubes were then shaken and 1 ml of the preparation was transferred into petri dishes containing potato dextrose agar (PDA) medium containing streptomycin (100ppm) for each sample (Agrios, 2004). The petri dishes were then incubated at room temperature for 5-7 days for possible fungal growth. ...
... One of the goals of seed treatment is to improve seed germination and protect seeds from pests and diseases. Seed treatment using biological agents (biological seed treatment agents) is an alternative as a substitute for synthetic chemicals [5]. We know that plant protection is an inseparable part of an overall agricultural ecosystem management system, so controlling plant-disturbing microorganisms by utilizing biological resources (biocontrol agents) is a top priority at this time. ...
Chili is one of the leading horticultural commodities that has high economic value and still requires serious handling, especially in increase production both in quality and quantity.The research was conducted at the Laboratory of Seed Science and Technology, Department of Agrotechnology, Faculty of Agriculture, Syiah Kuala Darussalam University, Banda Aceh. The research was conducted from April 2023 to June 2023.The design used in this study was a 7 x 2 Factorial Completely Randomized Design (CRD) with 3 replications, so there were 14 treatment combinations and 42 experimental units, each treatment consisting of 3 plants so that 126 plants were obtained. The results showed that the effect of rhizobacterial treatment on the germination process had a significantly increased effect on maximum growth potential, germination, vigor index and growth simultaneity compared to no treatment (control). Almost all rhizobacteria can increase the rate of seed germination. At the variable maximum growth potential, germination capacity, vigor index and growth simultaneity, there are two isolates that have the potential to be candidates for plant growth promoting rhizobacteria agents (PGPR) and these isolates, namely AD 7/1 and LABA F1 varieties significantly provide an increase in seed vigor and viability.
... The results obtained can also be due to the fact that severity measurements are subjective and can sometimes be prone to bias and experimental errors. Also, visual assessment of disease usually tends to overestimate disease severity, especially with low levels of infection [16]. [17]suggested that the visual assessments are made quickly and do not require expensive equipment, chemical analysis or highly trained personnel, but their subjective nature creates concern and determines that the accuracy and precision of the measurement of injuries are questionable. ...
Sugarcane cultivation is hindered by several biotic constraints of which viral disease plays a major disaster. This study was carried out to evaluate the virus disease situation of sugarcane germplasm in western Cameroon, consisting of three regions (Southwest, Northwest and West region). A survey was carried out in 66 villages in these regions. Landraces identified included SMU58, SBK36, SNC16, NBfPc48 and NBfAg53. Representative samples of the landraces were collected and grown in an experimental field in the Department of Plant Science, University of Buea. Canes were observed for virus disease symptoms eleven months after planting. Single leaf samples of the symptomatic plants were collected from 10 randomly selected plants constituted a batch sample. A total of 66 and 15 batch samples collected from the field and experimental plot respectively were tested for the detection of Sugarcane Mosaic Virus (SCMV) and Maize Streak Virus (MSV) by direct Double Antibody Sandwich ELISA (DAS-ELISA). Of the 66 composite samples tested for SCMV and MSV, 54 samples tested positive for at least one virus. Maize streak virus was the most prevalent, with an incidence of 11.25%. Mixed infection was also recorded. Sugarcane in western Cameroon is infected with some virus diseases though the prevalence is low. This is a course of concern.
... PM infection is strongly influenced by weather conditions such as temperature, humidity and rainfall. The most favourable temperature for infection is approximately 15-20°C, and spore germination is facilitated by high relative humidity, but the presence of free water hinders spore germination (Agrios, 2005;Cowger et al., 2012). Hence, the lower temperatures and higher rainfalls in winter could explain our observation. ...
Powdery mildew, caused by the biotrophic fungus Blumeria graminis DC. f. sp. avenae , is a widespread disease of oats, especially in the temperate regions of Western and Central Europe, and the use of resistant varieties is the most sustainable way to ensure stable yields. Therefore, the identification of robust and effective resistance to powdery mildew is of great interest for oat breeding. In contrast to race-specific resistance genes, adult plant resistance (APR) is generally considered to be more durable. The oat variety Firth, as well as related varieties such as Husky or Flämingstip, contains an unknown APR gene, which was previously located on chromosome 1D using DArT markers. The aim of this study was to confirm and refine the chromosomal location of this resistance gene, tentatively named Pm13. To this end, two independent experiments were carried out using different genetic material under natural infection conditions in the field: genome-wide association mapping (GWAS) in a diverse set of 250 oat lines grown in ten environments and QTL mapping in a HuskyxAVE1284 bi-parental population grown in three environments. Both approaches identified a QTL for powdery mildew resistance on the distal end of chromosome 1D in the hexaploid Sang oat genome. The locus explained up to 15 % of the phenotypic variance in GWAS and 64 % of the phenotypic variance in QTL mapping. Comparison of field data with results from laboratory leaf segment tests confirmed that Pm13 does indeed confer APR. The sequence information of the identified linked markers may allow the development of molecular markers useful for early selection of oat lines with high levels of APR.
... Fusarium spp. produces chlamydospores and microsclerotia, resilient structures enabling them to persist in the soil (Agrios, 2005 and selecting the right Trichoderma strains and optimizing environmental conditions are critical factors in achieving successful biocontrol (Harman et al., 2004). ...
Shallots are a type of plant used as a flavoring agent and are often affected by twisted disease caused by Fusarium spp. This study aims to determine the ability of organic material enriched by Trichoderma asperellum in controlling twisted disease, increasing production, and suppressing the population of Fusarium spp. in the soil. The research showed that compost and chicken manure enriched with T. asperellum in a ratio (200:1) were able to reduce the disease incidence compared to controls, in addition to increasing production and suppressing the population of Fusarium spp. in the soil. The colonies of Fusarium spp. in the soil were correlated with disease incidence in each treatment. The highest incidence of twisted disease was followed by the number of Fusarium spp. colonies. The microbial composition did not affect disease suppression when observed using a dependent method using PCR-RISA. The microbial composition with the dependent method using PCR RISA did not affect the suppression of the twisted disease in the shallot plants.
... Detecting diseases can be challenging for forecasters due to various environmental conditions, such as temperature and relative humidity. Fluctuations in these factors can complicate the identification and prediction of diseases (Adikaram et al., 1986, Agrios, 2004. Different crops in Nepal face specific diseases that have become significant concerns for pathologists. ...
... Fungal pathogens cause severe plant diseases, limiting plant yields as well as the quality of the products. Moreover, they have wide host spectra, causing diseases in economically important agricultural crops worldwide (Agrios, 2005). The increased resistance of pathogens, the fact that chemical fungicides have harmful compositions and underly adverse effects for the environment and consumers, force the management of plant diseases to become more complicated and therefore alternative plant protection strategies are currently being investigated. ...
... Sporisorium cruentum), head smut (Sphacelotheca reiliana) (syn. Sporisoriumholci sorghi) and long smut (Sporosporium ehrenbergii) have significant importance in affecting sorghum yield (Agrios, 2005). Covered kernel smut occurs in most regions where sorghum is grown (Aschalew et al., 2012;Merkuz and Getachew, 2012). ...
The Article is about Integrated Management of Covered Kernel smut disease of sorghum.
... Sporisorium cruentum), head smut (Sphacelotheca reiliana) (syn. Sporisoriumholci sorghi) and long smut (Sporosporium ehrenbergii) have significant importance in affecting sorghum yield (Agrios, 2005). Covered kernel smut occurs in most regions where sorghum is grown (Aschalew et al., 2012;Merkuz and Getachew, 2012). ...
Sorghum is multi-purpose crop that plays an important role in the socio-economic life of farming communities in Somaliland. However its production and productivity is threatened due to Covered kernel smut disease. A field experiment was carried out at Aburin Agricultural Research Center at Gabilay district in Somaliland in order to identify management options for Covered kernel smut disease of sorghum. The experiment consisted of 12 factorial treatment combinations of three varieties (i.e., Faruryogele, Abadro and Kuso) and three types of seed treatments which includes synthetic and bio-fungicides (i.e., Apron star 42WS%, Cow urine, and Neem seed kernel extract) and including Untreated control, laid out in RCBD with three replications. Parameters such as disease incidence, disease severity, phenological data, grain yield (kg)/plot, actual grain yield/plot, 1000 grains weight (g) and yield loss (%) were collected. The experiment result showed that highest disease (44.0%) incidence was recorded on untreated Kuso variety while lowest disease (4.33%) incidence was Apron star with Abadiro. Similarly, the highest disease severity (37%) was scored from Untreated Abadiro whereas lowest disease severity (4%) was scored from Abadiro with Apron star and Faruryogele with Apron star. Untreated Abadiro variety reached highest AUDPC (1036.0% days). The Apron star treated varieties had the lowest AUDPC and consistently showing markedly low infection rates indicating that they were more effective to the disease relative to the other seed treatments. The highest yield (1896 kg ha-1) was recorded from Faruryogele with Apron star and lowest (933 kg ha-1) was recorded from untreated Abadiro and Faruryogele. So, Apron star was effective to reduce the yield loss of sorghum and could be recommended to manage sorghum covered kernel smut. However, the experiment should be repeated across different environments over years in order to give the right recommendations and its rate may need to be well defined.
... Fusarium oxysporum f.sp. capsici merupakan salah satu patogen tular tanah penyebab penyakit layu fusarium pada tanaman cabai besar (Agrios, 2005). Kerugian akibat penyakit layu fusarium pada tanaman cabai cukup besar karena menyerang tanaman dari masa perkecambahan sampai dewasa. ...
Pemakaian pestisida sintetis untuk pengendalian hama dan penyakit tanaman sudah lama digunakan, dan diketahui sangat efektif, namun penggunaan secara terus menerus dan berulang ulang menyebabkan pencemaran lingkungan, toksisitas residu, resistensi patogen dan bahaya bagi pengguna. Berdasarkan hal tersebut maka penelitian pemanfaatan pestisida nabati perlu di intensifkan hingga didapatkan pestisida nabati yang handal yang efektifitasnya tidak beda dengan pestisida sintetis serta ramah lingkungan. Fusarium oxysporum merupakan salah satu patogen yang sangat sulit dikendalikan, merupakan patogen tular tanah yang mempunyai forma species yang sangat banyak, gejala serangan pada tanaman berupa layu dan busuk. Namanya tergatung inang yang diserangnya, diantaranya yang sangat merugikan petani adalah Fusarium oxysporum f. sp. cubense, penyebab penyakit layu fusarium tanaman pisang, kejadian penyakit mencapai 64,45% bahkan dapat memusnahkan perkebunan pisang Cavendish dalam waktu lima tahun. Fusarium oxysporum f.sp. capsici, menyerang tanaman cabai kegagalan panen hingga 50%, Fusarium oxysporum f.sp. lycopersici penyebab penyakit layu tanaman tomat serangan mencapai 50% dan Fusarium oxysporum f. sp. Zingiberi menyebabkan kehilangan hasil jahe mencapai 90%. Tulisan ini menyajikan beberapa pestisida nabati minyak atsiri yang telah diujikan terhadap jamur patogen Fusarium oxysporum penyebab penyakit layu dan busuk fusarium pada beberapa tanaman yang dibudidayakan, diharapkan pestisida nabati ini dapat mengurangi pemakaian pestisida sintetisABSTRACTThe use of synthetic pesticides to control pests and plant diseases has been used for a long time, and is known to be very effective, however, continuous and repeated use causes environmental pollution, residual toxicity, pathogen resistance and danger to users. Based on this, research on the development of the use of vegetable pesticides needs to be intensified in order to obtain reliable plant pesticides for controlling pests and plant diseases, which are not much different in effectiveness from synthetic pesticides and are environmentally friendly. Fusarium oxysporum is one of the pathogens that is very difficult to control, is a soil borne pathogen that has a very large number of species forms, with symptoms of attack on plants in the form of wilting and rot. Its name depends on the host it attacks, one of which is quite important and very detrimental to farmers is Fusarium oxysporum f. sp. cubense, Fusarium oxysporum f.sp. capsici, Fusarium oxysporum f.sp. lycopersici and Fusarium oxysporum f. sp. zingiberi. This article presents several essential oil vegetable pesticides that have been tested against the pathogenic fungus Fusarium oxysporum which causes fusarium wilt and rot in several cultivated plants. It is hoped that these vegetable pesticides can reduce the use of synthetic pesticides.
... Worldwide, 36.50% field loss occurs in all agricultural products, of which 10.2% is caused by insects (Agrios 2005). ...
In this study, outbreak conditions of Sunn pest, Eurygaster maura L., 1758 (Hemiptera: Scutelleridae), the main agricultural pest of wheat, Triticum aestivum L., 1753 (Poaceae: Poales) which is the most important crop of the Central Anatolia (Türkiye) in terms of cultivation area and production was investigated. For this purpose, population density of adult sunn pests in its overwintering site and wheat cultivation area were evaluated for Central Anatolian provinces for the years between 1988 and 2021. It is observed that population density of sunn pest reached the level that requires control in 1988 for the first time. After, there were three infestation periods up to 2021 and each of them lasted for 4 years. First of them occurred between 1993 and 1920. It is observed that when average density of overwintered adult sunn pests exceeds 30 per square meter, there can be infestation in all overwintering sites of Central Anatolia. Also, there is a correlation between this density and the intensity of the infestation. Throughout the infestation periods, average temperature was determined as 20ºC during the reproduction and development period, and it was recorded over 19ºC during the season when temperature changes and relocations were high in overwintering site.
... In some areas, this disease is a significant obstacle to sustaining productivity and quality, and when vulnerable cultivars are grown, the impact can be very severe. Smuts was one of the primary worries of farmers in the majority of wheat-growing countries up until the 20 th century (Agrios, 2005). Although they can transfer short distances, infected seeds are the primary means of spreading loose smut (Nielsen and Thomas, 1996). ...
... Storagerelated onion bulb rots have been associated with 11 distinct bacterial plant diseases, primarily identified through saturated scales and a light yellowish tint in infected bulbs (5,6). Storage-associated problems are predominantly attributed to microorganisms, with Pseudomonas and Pectobacterium identified as major contributors, leading to significant onion losses (7,8). Bacterial soft rot, prevalen t during storage or transit, commonly initiates through wounds caused by insect feeding or harvesting damage (9). ...
... Intensitas serangan suatu penyakit yang menyerang tanaman dipengaruhi oleh tiga faktor utama yaitu tanaman inang, patogen dan lingkungan, yang dikenal dengan konsep segitiga penyakit. Suatu penyakit dapat terjadi jika terdapat tanaman inang yang rentan, patogen yang ganas dan lingkungan yang mendukung untuk perkembangan patogen (Agrios, 2005). Jika ketiga faktor tersebut mendukung pertumbuhan patogennya maka penyakit akan dan berkembang. ...
Chili is an important vegetable commodity that is used in meeting daily needs, industrial and pharmaceutical raw materials. The disease that is most often found in chili plants and causes economic losses is anthracnose disease caused by Colletotrichum capsici. One alternative control technique that can be done using ecoenzymes. Salah satu alternatif teknik pengendalian yang dapat dilakukan dengan menggunakan ekoenzim. Penelitian disusun menggunakan Rancangan Acak Kelompok yang terdiri dari 6 perlakuan yaitu tanpa perlakuan ekoenzim (P0), 1 mL ekoenzim/500 mL air aquades (P1), 1 mL ekoenzim/750 mL water (P2), 1 mL ekoenzim/1000 mL water (P3), 1 Ml ekoenzim /1250 water (P4) dan 1 ml ekoenzim/1500 mL water (P5). The variable observed was the intensity of the attack of red chili anthracnose. The research data was analyzed variously followed by an honestly significant difference test at a 95% confidence level. Ecoenzyme treatment affects the intensity of anthracnose disease (C. capsici) attacks on chili plants (C. annuum L.) Ecoenzyme application with a concentration of 1 mL / 1250 mL of water can suppress the intensity of anthracnose disease attacks.
... Being a climacteric and perishable vegetable, most tomatoes fruits species have a very short life span. Global postharvest losses of tomato are as high as 30-40% (Agrios, 2005) but this is much higher in under developed countries in Africa like Nigeria due to lack of improve processing facilities. Nigeria is the second largest producer of tomato in Africa after Egypt and the sixteenth largest producer in the world (Ebimieowei et al., 2013a). ...
... This process leads to the development of lesions in the host and eventually Rathod et al. BMC Genomics (2023) 24:630 to the production of further infectious particles [28]. In addition, the susceptible infected plants exhibited more severe foliar symptoms than the control sample ( Fig. 1). ...
Background Puccinia arachidis fungus causes rust disease in the peanut plants (Arachis hypogaea L.), which leads to high yield loss. Metabolomic profiling of Arachis hypogaea was performed to identify the pathogen-induced production of metabolites involved in the defense mechanism of peanut plants. In this study, two peanut genotypes, one susceptible (JL-24) and one resistant (GPBD-4) were inoculated with Puccinia arachidis fungal pathogen. The metabolic response was assessed at the control stage (0 day without inoculation), 2 DAI (Day after inoculation), 4 DAI and 6 DAI by Gas Chromatography-Mass Spectrometry (GC-MS). Results About 61 metabolites were identified by NIST library, comprising sugars, phenols, fatty acids, carboxylic acids and sugar alcohols. Sugars and fatty acids were predominant in leaf extracts compared to other metabolites. Concentration of different metabolites such as salicylic acid, mannitol, flavonoid, 9,12-octadecadienoic acid, linolenic acid and glucopyranoside were higher in resistant genotype than in susceptible genotype during infection. Systemic acquired resistance (SAR) and hypersensitive reaction (HR) components such as oxalic acid was elevated in resistant genotype during pathogen infection. Partial least square-discriminant analysis (PLS-DA) was applied to GC-MS data for revealing metabolites profile between resistant and susceptible genotype during infection. Conclusion The phenol content and oxidative enzyme activity i.e. catalase, peroxidase and polyphenol oxidase were found to be very high at 4 DAI in resistant genotype (p-value < 0.01). This metabolic approach provides information about bioactive plant metabolites and their application in crop protection and marker-assisted plant breeding.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12864-023-09725-3.
... Therefore, it is paramount to integrate these cultural methods with other control strategies (Shenge et al. 2014). Such strategies include Chemical control which weakens or kills the pathogens (Vidaver and Lambrecht 2004;Agrios 2005). Managing F. oxysporum and X. campestris is mainly through chemical soil fumigation. ...
Gitari FM, Githae EW, Kuria EK. 2023. Phytochemical analysis and antimicrobial activity of Tamarindus indica extracts against Fusarium oxysporum and Xanthomonas campestris. Intl J Trop Drylands 7: 73-82. Plant-pathogenic bacteria and fungi are a major threat to biodiversity and food security worldwide. The pathogens are difficult to control using cultural methods and have sometimes acquired resistance to conventional pesticides. This has necessitated the search for more efficient active compounds against them. One promising source of such compounds is tropical-medicinal plants such as Tamarindus indica L. This study first determined the phytochemical composition of T. indica extracts from different parts (leaves, bark, roots, and pods). Then it evaluated in-vitro the antimicrobial activity against plant pathogenic bacteria (Xanthomonas campestris) and fungi (Fusarium oxysporum). Crude extracts were obtained using different solvents (dichloromethane, methanol, and acetone). The analysis revealed the presence of nine pharmaco-active phytochemicals; methanol extracts had the highest concentrations of these phytochemicals. All extracts demonstrated inhibitory effects against F. oxysporum. However, the extracts did not show any antimicrobial effect against X. campestris. There was a significant difference (p<0.05) in the percentage of inhibition of F. oxysporum growth by different extracts. Generally, high growth inhibition was observed in media containing different plant extracts at 250 and 500 ppm concentrations. For acetone extracts, the highest inhibition (71.042%) was induced by root extract at a 250 ppm concentration, whereas for dichloromethane extracts, the highest inhibition (68.811%) was induced by 500 ppm of leaf extract. Methanol extracts from stem recorded the highest inhibition of 86.953% at concentrations of 125 ppm. This was followed by root extracts (75.169% inhibition) at 500 ppm. The T. indica, therefore, has great potential as a source of bio-pesticide for use in integrated pest management of F. oxysporum.
... isolated in this research has antagonistic properties against wilt disease in several plants (Suryanti, 2013). This group of molds includes cosmopolitan properties with a very wide distribution and can be found in various places (Agrios, 2005). Aspergillus sp. can also be used to inhibit pathogenic molds such as Fusarium oxysporum (Suniti & Sudarma, 2016). ...
Mango’s mistletoe is one of the herbal plants’ rich in bioactivity. Secondary metabolites are not only produced by plants but also by microorganisms that live in tissues. One of these microorganisms is endophytic mold. The ability of endophytic molds to synthesize secondary metabolites is an opportunity for large-scale production in a short time without causing the exploitation of natural materials. This research aimed to explore and identify endophytic molds from the leaves and stem of the mango mistletoe to obtain the genus of molds. The stages of this research consisted of isolation by direct planting with sterilization, purification, growth rate measurement, characterization, and identification carried out macroscopically and microscopically. DBM 1 and DBM 2 belong to Aspergillus sp., DBM 3 belongs to Cladosporium sp., DBM 4 belongs to Neurospora sp., TDBM 1, TDBM 2, and TDBM 3 belong to Hormiscium sp. The growth rate of Aspergillus sp. relatively fast, with the increase in diameter of Aspergillus sp.1 colony from 2.45 cm to 5.05 cm and that of Aspergillus sp.2 from 2.73 cm to 5.35 cm. In the Cladosporium sp., there was an exponential phase with an increase in diameter from 2.15 cm to 4.65 cm. In Neurospora sp., there was an exponential phase with an increase in diameter from 0.63 cm to 3.65 cm. The growth rate of Hormiscium sp. is quite fast, with an exponential phase with an increase in the diameter of the colonies of Hormiscium sp.1 from 2.63 cm to 7.21 cm, Hormiscium sp.2 from 2.45 cm to 6.94 cm and Hormiscium sp.3 from 2.85 cm to 7.85 cm.
... Bacteria are also important in controlling soil-borne pathogens that can decrease the capacity of roots to absorb water and nutrients [2,3] . Bacterial wilt is a widely spread soil born bacterial disease of Solanum melongena (Brinjal) plant which occurs throughout of the world [4]. Ralstonia solanacearum is the disease causing agent of bacterial wilt, brown rot or southern wilt in Brinjal, Tomato, Tobacco and in few of ornamental plants and also moko disease of Banana [5] . ...
... In dual culture, some Trichoderma isolates formed brownish inhibition zones when came in contact with R. solani while most Trichoderma isolates appeared to overgrow the colony of the pathogen. The browning zones formed as a result of mycelia being parasitized through the mechanism of coiling, encircling and lysis of R. solani hyphae by Trichoderma (Agrios, 2005, Askew & Laing, 1994. Timila et al. (2015) Trichoderma isolates from Nepal. ...
The biological effectiveness of twenty-eight native isolates of Trichoderma along with two known species (Trichoderma viride and Trichoderma harzianum) were tested against Rhizoctonia solani using dual culture technique. Of them, seven isolates and the two species of Trichoderma were tested in pot culture under net-house conditions against wirestem disease of cauliflower caused by R. solani. Inhibitory effects on dual culture were statistically very significant for all tested Trichoderma. Thirteen Trichoderma isolates exhibited more than 90% bio-control index and twenty-three isolates had more or at par with T. viride and T. harzianum. In an in-vitro trial, isolate from Dhankuta (Pakhribas) was most effective against R. solani as evident by the highest bio-control index at 6 days after incubation. Similar to this, in an in-vivo experiment, tested isolates of Trichoderma contributed more or less in the plant canopy area, root length and shoot circumference attributes. Trichoderma isolates significantly contributed to root dry matter and biomass while there was a highly significant difference in reduction of disease severity. T. harzianum and the isolate from Dhankuta (Pakhribas) were most effective for the control of wirestem disease
... It commonly infects cereal grains, legumes, and nuts. Postharvest infections in these crops is associated with mycotoxin production (Agrios 2005, Chang et al. 2009, Hedayati et al. 2007), among which aflatoxins including B1, B2, G1, and G2 are the most toxic ones (Horn et al. 1996, Kumar et al. 2017, Li et al. 2022). There is a vast genetic diversity in the populations of A. flavus, as is reflected in their morphology, mycotoxins production (Horn et al. 1996), vegetative compatibility groups (Wicklow et al. 1998), and hosts (Amaike & Keller, 2011). ...
Ascomycota includes a large number of species that lack a known sexual stage but have a hidden potential for sexual reproduction, among which is Aspergillus flavus, an opportunistic aflatoxin-producing pathogen. The sexual stage of this heterothallic fungus results from crossing between strains with opposite mating types that belong to different vegetative compatibility groups. Here, twenty A. flavus Iranian isolates were investigated for heterothallism and sexual reproduction. The mating type genes MAT1-1 and MAT1-2 were explored using specific primers and multiplex PCR. The results indicated an equal frequency of mating types (1:1) in the investigated A. flavus isolates, indicating heterothallism, and possible sexual reproduction. The cross-cultures on Mixed Cereal Agar (MCA) and Aspergillus Complete Medium (ACM) induced the sexual phase. After 6 to 11 months, 33.16% of the crosses led to sexual reproduction and the sexual reproductive organ of the fungus appeared at the contact lines of the crosses. Scanning Electron Microscopy (SEM) analyses revealed multiple asci and ascospores, which were produced in the pseudoparenchymatous stromata. Ascospore production was more efficient in ACM than in the MCA. Our findings place the Iranian A. flavus in the genus Petromyces, as Petromyces flavus.
... The result is the same with [1] because of senescence, the positive correlation indicates that the severity of the Leaf blotch increased as the crop stage proceeded. Because the crop loses its physical and chemical barriers as it matures, the disease can easily infiltrate and develop on the crop [6]. This finding is consistent with a previous study that found Leaf blotch disease to be widespread in central Ethiopia's highlands [1], [32], as well as in Tigray, Southern Nations, Nationalities, and People's Region and Amhara highlands [8,34]. ...
Wheat rusts and Septoria tritici blotch are among the most important constraints in wheat production in Ethiopia.
The aim of this study was to study the geographical distribution of major wheat diseases such as stem rust, yellow
rust, leaf rust & STB in central highland parts of Ethiopia and determine the reaction of wheat cultivars to wheat
rusts in the country during 2020 cropping season. A total of 48 wheat fields were surveyed in major wheat growing
areas of Oromia & Amhara Regions of South West Shewa, West Shewa & North shewa zones. Septoria tritici blotch
and yellow rust were the most widely distributed disease in the surveyed fields with a prevalence percentage of 100
& 68.5% respectively. The overall mean incidence values for Septoria tritici blotch, yellow rust, stem rust and leaf
rust were 73.32, 26.9, 15.7 and 0.12%, respectively. Likewise, the overall mean severities were 22.6, 9.8, 8.6 and
0.01%, respectively in the same order. The incidences and severities of wheat rusts varied among wheat varieties
in the season. Most varieties showed moderately susceptible to susceptible responses against yellow rust and stem
rust populations. The predominance of susceptible varieties can be an important recipe for the development of rust
epidemics in Ethiopia. The present findings confirmed the importance of Septoria tritici blotch, yellow rust and stem
rust in Ethiopia. Hence, continuous supply of resistance varieties is needed to avoid wheat disease epidemics in the
country.
Plant secondary metabolites, including essential oils (EOs), are becoming an alternative to traditional methods of controlling phytopathogens. In the present work we evaluated the antifungal
activity of EOs from two populations of Aloysia polystachya on the causal agent of gray mold, Botrytis cinerea. The chemical composition of EOs showed carvone and α-thujone as the main components of each EO, determining that they were two different chemotypes. The antifungal
effect of both chemotypes against B. cinerea was evaluated in their vapor phase, at different concentrations. The MIC for the carvone-rich chemotype was 71 μL L1, while the α-thujone-rich chemotype completely inhibited growth at a concentration of 189 μL L1. Both chemotypes significantly inhibited the germination of fungal conidia. The normal morphology of the hyphae of B. cinerea was compromised in the presence of both chemotypes, showing flattening and emptying of the content, compared to the untreated mycelium. The effect of the chemotypes on the disease caused by the fungus was also evaluated in artificially inoculated tomatoes, with the carvone-rich chemotype being more effective in reducing the characteristic symptoms. None of the chemotypes produced alterations in postharvest quality parameters. Our data allow us to propose the EO of A. polystachya with abundant content of the terpene carvone, as a natural strategy for the control of the pathogen B. cinerea. This research is important to show how the existence of variants within the same botanical species implies differences in their effectiveness as fungicides.
The paper presents the results of a study of the fungal component of the microbiome associated with six-toothed bark beetle on the territory of Belarus to clarify the role of this xylophage as a vector of dangerous phytopathogenic fungi. More than 360 pure cultures of fungi isolated from the surface and hemocoel of Ips sexdentatus were analyzed by cultural-morphological and molecular-genetic methods. 35 species of fungi from 25 genera of 17 families in 3 divisions were identi ed. Based on their impact on the stored wood, all species are conventionally classi ed into three groups: (1) fungi that cause discoloration of wood (mold, blue stain, etc.), (2) fungi that cause rot of growing forest and harvested wood, and (3) fungi whose . Five species of fungi from the family Ophiostomatacea e were identi ed: Leptographium Lagerb. & Melin sp., Ophiostoma ips (Rumbold) Nannf., O. minus (Hedgc.) Syd. & P. Syd., O. canum (Münch) Syd. & P. Syd., and O. piceae (Münch) Syd. & P. Syd. associated with blue wood. Heterobasidion annosum (Fr.) Bref. was found in 7.8% of the studied samples of the fungal ora. Fairly high frequency of occurrence con rms the participation of the six-toothed bark beetle in the formation of complex centres of pine desiccation in the territory of Belarus. In the I. sexdentatus population, a signi cant proportion of entomopathogenic fungi (11.4%) was recorded using the molecular genetic method, which may indicate natural processes of self-regulation, or the attenuation of the outbreak of bark beetles in Belarus.
En los estados de Michoacán, México y California, EUA, la producción de zarzamora (Rubus sp.) se ve afectada por una marchitez que ocasiona la pérdida de miles de hectáreas. En el presente trabajo se identificó el agente causal de la enfermedad y propuso alternativas de control con microorganismos antagonistas. En el año 2022 de un huerto en Tocumbo, Michoacán, se aisló e identificó morfológicamente al agente causal de la enfermedad. Se realizó un bioensayo preliminar en laboratorio con cepas de B. subtilis, B. amyloliquefaciens, P. fluorescens y Trichoderma spp, nativas de Tacámbaro y Taretan, Mich. Las cepas sobresalientes se probaron en invernadero en plantas de zarzamora cv Tupy de forma preventiva y como control, bajo un diseño experimental de bloques al azar con seis repeticiones. En las pruebas preliminares todas las cepas utilizadas mostraron una inhibición del crecimiento micelial del patógeno superior al 50%, sobresaliendo Trichoderma sp. de Tacámbaro, B. subtilis y P. fluorescens. En las pruebas realizadas in situ los tratamientos aplicados de forma preventiva disminuyeron la incidencia de marchitez desde 57 hasta 66%. En términos de severidad y altura de la planta destacó Trichoderma sp., mientras que el porcentaje de necrosis radicular disminuyó desde 56 hasta 70% con todos los tratamientos. Los tratamientos de control también mostraron eficacia antagonista, aunque en menor medida, disminuyeron la incidencia de marchitez desde 2 al 58% y los porcentajes de necrosis radicular desde 19 a 62%. Los microorganismos antagonistas pueden incorporarse como una estrategia de manejo integral con gran eficiencia.
Bitkilerin bakteriyel hastalıkları arasında en yaygın ve yıkıcı kayıplara sebep olan bakterilerden birisi Xanthomonas türlerinin içinde bulunduğu gruptur. Xanthomonas cinsi, çok çeşitli konukçuları etkileyen, ekonomik açıdan önemli birçok bitki patojeni türü içerir. Çoğu tür, bitki, tohum, ve gıda ticareti üzerinde küresel, ekonomik ve çevresel etkiye sahip bitki hastalıklarından sorumludur. Konukçu bitkilerde nekroz, kanserler, lekeler ve yanıklıklar dahil olmak üzere çeşitli belirtilere neden olurlar ve bitkilerin meyveler, yapraklar ve gövdeler dahil olmak üzere farklı kısımlarını etkilerler. Xanthomonas cinsi fitopatolojik açıdan çeşitlilik durumu ve fenotipik farklılıkları açısından önemli bir cinstir. Ekonomik açıdan önemli olması sebebi ile geniş taksonomi çalışmalarına ve yüzlerce bilimsel çalışmaya konu olmuştur. Bu derlemede, Xanthomonas cinsinin önemi, Xanthomonas cinsi bakterilerin genel olarak tanımı, biyolojisi, taksonomisi, epidemiyolojisi, endüstriyel kullanımı, konukçu patojen ilişkileri, tanı yöntemleri ve mücadele olanakları tanımlanmıştır.
Plant defence mechanisms against plant pathogens are intricate
and multifaceted processes essential for the survival and health of plants.
The first line of defence often involves structural defence mechanism
which act as a physical barrier such as cell walls, followed by chemical
defence mechanism including the synthesis of antimicrobial compounds
like phytoalexins and pathogenesis-related proteins, the production of
reactive oxygen species (ROS) to damage pathogens, and the activation
of defence-related signalling pathways, such as the salicylic acid pathway.
Additionally, plants have evolved sophisticated immune receptors and
receptors that enable them to differentiate between beneficial and harmful
microorganisms. This intricate network of defences not only safeguards
plant health but also has implications for agriculture and crop protection
strategies. Understanding the underlying mechanisms of plant defense is
crucial for developing sustainable approaches to enhance crop resistance
and reduce the reliance on chemical pesticides. This chapter provides
insights into the fascinating world of plant-pathogen interactions and the
evolving strategies employed by plants to defend against an ever-changing
array of threats, highlighting the significance of this research in
agriculture and plant biology.
Research into the effects of climate change on plant diseases is limited, as much of the work focuses on the effects of a single climate or climate change on host, pathogen, or their interactions under controlled conditions. The results from various research work show that climate change may alter the stages and levels of pathogen development, alter host resistance, and cause changes in the physiology of host-pathogen interactions. The most likely consequences are changes in the distribution of host and pathogen habitats and altered plant losses, which are due in part to change in the effectiveness of control strategies. Climate change affects the incidence, prevalence and severity of plant diseases. Ultimately, advances include understanding the nature and extent of evolutionary adaptation of plants and
pathogens, and moving beyond short-term variability to multi-year trends to determine plant fate under future climate change (Jeremy et al., 2020). Prediction of future requirements in disease management is of great interest for agro – industries, extension, services and practical farmers (Zayan et al., 2019). Recent advances in testing and modeling techniques offer great promise of developing an improved ability to assess the impact of climate change and mitigation. Compared with major technological, environmental, and societal changes affecting agricultural production during the next century, climate change may be less significant; however, it will add another complexity and uncertainty to a system that is already extremely difficult to manage in a sustainable manner. Intensive research on climate change issues can lead to improved understanding and control of plant diseases in light of current and future adverse weather conditions.
Keywords : Climate change, Host-pathogen interactions, Prevalence, Sustainable, Intensive.
As an archipelago regency, the Sangihe Islands has been known for its expanses of coconut plantations, which are one of the local community's primary commodities and sources of income. An inventory of pests and diseases specific to coconut in this area has never been carried out, and this information is needed, especially regarding sustainable coconut management. This study aimed to determine the presence of coconut pests and diseases in Sangihe and to obtain the latest conditions related to pests and disease incidence. The research was carried out through several stages, i.e., interviewing farmers, sampling, and identifying and documenting pests and diseases. The climate condition of Sangihe Island is classified as type A (very wet), with an average rainfall of 248 mm, temperature of 27 C, and humidity of 83% from 2017-2021. This condition is one of the determining factors for the existence of pest attacks and disease-causing pathogen infection on coconut. Pests dominated as disturbing organisms compared to diseases caused by plant pathogens. These pests included grasshoppers, coconut rhinoceros beetles, coconut hispine beetles, coconut mites, and white-tailed mice. Observations of the damage intensity by Sexava coriaceae were conducted in the Tahuna Barat district by selecting three land categories. The most severe damage occurred in field B (mostly planted with Hybrid Coconuts) with a percentage of 39%, while the lowest damage was in field C (mostly planted with Tall Coconuts), at 17%. The major disease detected was a gray leaf spot caused by the fungus Pestalotiopsis palmarum. The highest disease incidence and severity were found in Tabukan Utara district with percentages of 43% and 22% respectively, while the lowest incidence and severity were found in Tahuna Barat district with percentages of 3% and 1%, respectively.
This review deals with major diseases caused by fungi and oomycetes in the citrus supply chain, including post-harvest fruit diseases, and summarizes the strategies and techniques that may be adopted to prevent the damages and losses they cause. Its scope is to highlight the contribute that smart technologies provide towards new solutions for sustainable and safe management strategies of these diseases. Particular attention is given to the application of biopesticides, natural substances, resistance inducers and biostimulants to prevent fruit rots. The review focuses also on mycotoxins and mycotoxigenic fungi that contaminate fresh fruit and food products derived from citrus fruit, an aspect that has been little investigated and regulated so far. An additional relevant aspect addressed by the review is the early detection and routine diagnosis of fungal and oomycete pathogens that threat the international trade and long-distance shipment of citrus fruit, with a particular emphasis on quarantine pathogens. In this respect, the opportunities offered by new practical, rapid, sensitive and robust molecular diagnostic methods are briefly discussed.
Çalışma, Kahramanmaraş Sütçü İmam Üniversitesi, Ziraat Fakültesi, Bitki Koruma Bölümü uygulama arazisinde 2021-2022 yıllarında yürütülmüştür. Bu araştırmada tarla küskütünün (Cuscuta campestris Yunck.) bakla (Vicia faba L.)’nın fenolojik ve pomolojik özelliklerine etkisi araştırılmıştır. Bakla deneme alanı tarla küskütü ile infekteli ve infektesiz olmak üzere iki karakterli ve 4 tekrarlı olarak tesadüf blokları deneme desenine göre planlanmıştır. Deneme alanında verilerin iki yıllık ortalamasına göre; C. campestris yoğunluğu 19.25 adet/m2 olarak hesaplanmıştır. C. campestris’in infeksiyonu sonucunda V. faba’nın fenolojik özelliklerinden; bakla bitki boy gelişimini %71.79, çiçek sayısını %62.16, dal sayısını %57.90, V. faba hasat sayısını %55.56 ve bakla verimini %66.31 oranında olumsuz etkilemiştir. V. faba’nın pomolojik özelliklerinden; bakla meyve boyunu %42.52, bakla meyve ağırlığını %31.47, meyve sayısını %76.80 oranında olumsuz etkilemiştir. Bu araştırma sonucunda taze baklanın analiz sonucuna göre C. campestris infeksiyonu sonrasında V. faba meyve proteini, demir, karbonhidrat ve potasyum oranlarında sırasıyla; %24.39, 21.60, 17.78 ve 2.27 azalışa neden olmuştur. Bu araştırmada elde edilen sonuçlara göre, C. campestris infeksiyonun V. faba kültür bitkisi için önemli bir tehdit olduğu tespit edilmiştir.
Among all diseases of wheat, seed-borne diseases such as smuts and bunts are found in every
area where the wheat is grown. It is one of quarantine diseases of wheat that reduces the quality
of grain seeds. Loose smut of wheat is occurred in cool and moist climate conditions. The
successful infection of loose smut can occur after the anthesis. The pathogen remains dormant in
the mature seed and germinates with germinating seeds. The mycelium of the fungus grows in
the crown node and finally invades the inflorescence tissues. It develops with the seed embryo. It
is disseminated by infected seeds and air by short distance. The pathogen has different types of
host range especially all species of triticum. It is also pathogenic on Aegilops and rye (secale
cereal). Most of the inoculum sources of loose smut are infected wheat seeds and air borne
teliospores from smutted heads. In every infected area of wheat by loose smut, a new race may
arise by recombination of pre-existing virulence genes or through mutations. So, an integrated
approach is needed for the effective control of the diseases and production and maintenance of
pathogen-free seed in the field and during storage. Different types of management systems such
as using of certified seeds treated with protectant fungicides, planting of resistant cultivars is
very important.
Antepfıstığı (Pistacia vera L.) Siirt ilinde yetişen en önemli tarımsal ürünlerin başında gelmektedir. Antepfıstığı bahçelerinde son yıllarda kök çürüklüğü ve solgunluk gibi belirtiler gözlemlenmiş ve ağaçlarda kurumalar tespit edilmiştir. Bu çalışmanın amacı bu kurumalara neden olan toprak kökenli fungal patojenlerinin belirlenmesidır. Çalışmaları 2021-2022 yılları boyunca Siirt ili Merkez, Eruh, Şirvan, Kurtalan ilçeleri ve köylerinde güdümlü sürvey olarak yürütülmüştür. Hastalık belirtisi gösteren ağaçlardan fungus izole edilmiş ve morfolojik ve moleküller olarak tanılanmıştır. Patojenisite çalışması, bir yaşındaki Siirt çeşidi üzerinde yapılmış ve patojen izolatlar belirlenmiştir. Çalışma sonucunda ağırlıklı olarak Fusarium türleri (F.solani, F.oxysporum, F.verticillioides, F.equseti, F. acuminatum, F. avenaceaum, Fusarium proliferatum, F. brchygibbosum, Fusarium spp.,), ile Diaporthe hongkongensis, Scydalidium sp., Rosellinia sp., Nectria diminuta, Neoscytalidium dimitatum, Rhizoctonia solani, Macrophomina phaseolina, Phoma spp, ve Cylindrocarpon spp., izole edilmiş ve bunların farklı oranlarda patojen oldukları tespit edilmiştir.
This book comprises the latest topics of microbiology, agriculture, botany and biochemistry. It also reflects the modern concepts in biological sciences. Advances in biological and agricultural sciences have been made in modern era. Different plants and animals proteins are playing important role in gene expression at cellular and molecular level. Figures and texts are written in organized form to improve the quality of the publication. Illustration of the figures has been presented with clear description and modern concepts that have been taken from different sources. All authors have contributed in this book publication in particular chapter section with
full devotion and handwork. References have been presented at the end of the book in proper style.
Apple scab, caused by the fungus Venturia inaequalis, is one of the most damaging diseases of cultivated apples (Malus x domestica) worldwide. It results in huge losses as it diminishes fruit quality and impacts tree growth. Current management revolves around the application of fungicides, however the number of sprays required per season is unsustainable and expensive. Further to this, populations of V. inaequalis have developed fungicide resistance. Breeding new cultivars with higher levels of resistance to scab is a priority, however, this process is long, so introducing mixed cultivar orchards may be a faster solution. We reviewed the general principles of using mixtures to manage plant diseases, and then considered specifically using mixed cultivars to manage apple scab in commercial production. Limited field studies have demonstrated the potential of using mixture to suppress apple scab development; but scab super-races that could emerge from mixture can pose a significant risk in commercial production. However, recent research on population genetics of apple scab in monoculture and mixed orchards suggests that the risk of super-race emergence is probably over-stated, because assortative mating among lesions on the same leaves is likely to occur, rather than commonly assumed random mating. Thus, we conclude that cultivar mixtures can contribute towards sustainable scab management, particularly in commercial cider apple production.
On rice (Oryza sativa L.), more than 70 diseases caused by fungi, bacteria, viruses, and nematodes have been listed. Among them, the blast disease caused by Magnaporthe oryzae B. Couch (syn. Pyricularia oryzae Cavara) seriously threatens global rice production worldwide. Effective management strategies such as the use of resistant cultivars and the application of fungicides individually cannot sustainably contain rice blast disease, because of the emergence of resistance genes and environmental threats. Therefore, applying bioagents to reduce M. oryzae infections, complete other strategies, and reduce pesticide dependence. The present work was carried out to evaluate the potential of not only plant rhizosphere-associated fungi in controlling Magnaporthe oryzae but also the effectiveness of five fungicides in coculture in vitro. Twenty-three biocontrol fungi mainly Trichoderma and Penicillium evaluated on six M. oryzae isolates were found to reduce pathogen growth in dual culture assay. The results obtained highlighted the good ability of bioagents to inhibit the growth of M. oryzae by 82.7 to 97% at 7 days after incubation. In addition, the fungicides tested namely Amistar, Horizon, Opu, Spartaktak, and Signum successfully inhibited the mycelial growth of M. oryzae. The major outcome of our study was evidence that all M. oryzae isolates were susceptible to the fungicides tested through their concentration (ppm) of 50% (EC50). No pathogen isolate was hypersensitive or resistant to fungicides with the EC50 average values of 0.24, 0.25, 0.28, 0.33, and 0.38 mg/l respectively for Spartak, Signum, Horizon, Amistar, and Opus. These good bioagents must be tested on plants in the greenhouse and the best of them could be used in IPM strategy with the combination of resistant cultivars and a reasoned use of fungicides for blast disease control.
Agrobacterium is a well-studied plant pathogen, which has the unique ability to transfer DNA and protein into a number of eukaryotes. The DNA is integrated randomly into the plant genome where it is expressed, thereby leading to the disease crown gall. This system is a paradigm for the interaction of a number of plant and animal pathogens which transfer proteins into their host cells. In Agrobacterium, the tumour inducing (Ti) plasmid codes for the functions specifically required for the transfer process. These genes, termed virulence or vir genes, are activated by plant signal molecules acting through a two component regulatory system. A key structure coded by 11 genes of the virB operon is a pilus, synthesized at 20 °C, but poorly at 25 °C. How this pilus functions in DNA and protein transfer is unclear, but homologous genes are found in many animal pathogens. In addition to Ti plasmid-encoded vir genes, chromosomal virulence genes have also been identified. However, these mutations are often pleiotropic because they involve both the normal physiology of Agrobacterium as well as the metabolism of Agrobacterium when it is associated with plant cells. Based on 16S ribosomal RNA sequencing, Agrobacterium is closely related to the intracellular pathogen of animals, Brucella. Several chromosomal mutations of Agrobacterium required for virulence in plants are also required for invasion of animal host cells by Brucella.
Geminiviruses transmitted by Bemisia spp. (Hemiptera: Homoptera: Aleyrodidae) cause serious disease problems in dicotyledonous vegetable and fiber crops worldwide. The introduction of new Bemisia biotype, a whitefly with a wide host range, into the Western Hemisphere in the 1980s, has been followed by the appearance of apparently new geminiviruses in Florida like tomato mottle virus, cabbage leaf curl virus, bean golden mosaic virus and other geminiviruses infecting vegetables in the Caribbean, Mexico, and Central America.
A new foliar disease of dry bean, nematode angular leaf spot (NALS). is caused by Aphelenchoides ritzemabosi. The disease is typified by numerous dark, angular lesions on leaves and occasionally a superficial necrosis on the upper surface of the petiole. Diagnosis of NALS is based on the presence of foliar symptoms and recovery of nematodes from symptomatic tissue. Infested fields were infrequent in a field survey of 7.175 ha in Wyoming conducted during a 3-year period. The field survey represented 17% of the crop harvested during those years. Therefore, it is unlikely that NALS will cause economic yield loss unless conditions for nematode survival and foliar parasitism are unusually favorable. The nematode is also known to parasitize alfalfa foliage in Wyoming and other western states. Infested dry bean fields found during the survey had a recent history of alfalfa production. Therefore, alfalfa and dry bean crop rotation provides a potential mechanism for nematode survival. Parasitic nematodes persisted in air-dried bean leaf tissue for at least 27 months, which suggests that persistence of NALS inoculum in crop debris is likely to occur in the field.
Almond fruit of cv. Nonpareil with slightly (1 to 10%), partially (15 to 40%) or almost completely (70 to 95%) abscised hulls were inoculated with Rhizopus stolonifer in 1991 and with R. stolonifer or Monilinia fructicola in 1992. More leaf death occurred both years near inoculated fruits with slightly or partially abscised hulls than near fruits with almost completely abscised hulls. Leaf death was greater near hulls inoculated with M. fructicola than with R. stolonifer in 1992. Disease severity did not differ among fruit with partially abscised hulls inoculated with 10 3 , 10 4 , or 10 5 spores of R. stolonifer per ml in 1991, and with the same concentrations of R. stolonifer, M. fructicola, or M. laxa in 1992. More leaf death occurred near fruit inoculated with M. laxa than with R. stolonifer and M. fructicola in 1992.
