Sclerotinia sclerotiorum によるキョウナ菌核病 (新称) の発生

A new disease causing the tan to light brown blighted stems and pods has occurred in 2.6% pea (Pisum sativum L.) plants with an average disease severity rating of 3.7 in Chapainawabganj district, Bangladesh. A fungus with white appressed mycelia and large sclerotia was consistently isolated from symptomatic tissues. The fungus formed funnel-shaped apothecia with sac-like ascus and endogenously formed ascospores. Healthy pea plants inoculated with the fungus produced typical white mold symptoms. The internal transcribed spacer sequences of the fungus were 100% similar to that recovered from an epitype of Sclerotinia sclerotiorum, considering the fungus to be the causative agent of white mold. Mycelial growth and sclerotial development of S. sclerotiorum were favored at 20°C and pH 5.0. Glucose was the best carbon sources to support hyphal growth and sclerotia formation. Bavistin and Amistar Top inhibited the radial growth of the fungus completely at the lowest concentration. In planta, foliar application of Amistar Top showed the considerable potential to control the disease at 1.0% concentration until 7 days after spraying, while Bavistin prevented infection significantly until 15 days after spraying. A large majority (70.93%) of genotypes including tested released pea cultivars were susceptible, while six genotypes (6.98%) appeared resistant to the disease. These results could be important for management strategies aiming to control the incidence of S. Sclerotinia and eliminate yield loss in pea.

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White Mold on Pea Caused by Sclerotinia sclerotiorum: A New Threat for Pea Cultivation in Bangladesh

Pea (Pisum sativum L.) is of global importance as a food crop for its edible pod and seed. A new disease causing the tan to light brown blighted stems and pods has occurred in pea (P. sativum L.) plants in Chapainawabganj district, Bangladesh. A fungus with white-appressed mycelia and large sclerotia was consistently isolated from symptomatic tissues. The fungus formed funnel-shaped apothecia with sac-like ascus and endogenously formed ascospores. Healthy pea plants inoculated with the fungus produced typical white mold symptoms. The internal transcribed spacer sequences of the fungus were 100% similar to Sclerotinia sclerotiorum, considering the fungus to be the causative agent of white mold disease in pea, which was the first record in Bangladesh. Mycelial growth and sclerotial development of S. sclerotiorum were favored at 20°C and pH 5.0. Glucose was the best carbon source to support hyphal growth and sclerotia formation. Bavistin and Amistar Top inhibited the radial growth of the fungus completely at the lowest concentration. In planta, foliar application of Amistar Top showed the considerable potential to control the disease at 1.0% concentration until 7 days after spraying, while Bavistin prevented infection significantly until 15 days after spraying. A large majority (70.93%) of genotypes, including tested released pea cultivars, were susceptible, while six genotypes (6.98%) appeared resistant to the disease. These results on identification, characterization, host resistance, and fungicidal control of white mold could be valuable to achieve improved management of a new disease problem for pea cultivation.

First characterization of a newly emerging phytopathogen, Sclerotinia sclerotiorum causing white mold in pea.

Potato brown spot caused by Alternaria alternata (Fr.) Keissler is one of the most destructive diseases of potato worldwide. The present study was conducted to identify the causal agent, and to test the efficacy of several fungicides with different modes of actions against A. alternata. Five different chemical fungicides including; Copper oxychloride (Sufer Copper Oxychloride® 50% WP), Carbendazim (Carbendazim Aria® 60% WP), Penconazole (Penconazole®  20% WE) , Mancozeb (Qadri Mancozeb®  80% WP) and Flutriafol 6.94% + Tebuconazole 20.8% (Topgaurd® 30% SC) were tested at four different concentrations of; 20, 100, 300 and 500 mg l, using the poisoned food technique. Among the tested fungicides, the highest in vitro inhibition (%) of mycelial growth of the pathogen was recorded on using Flutriafol 6.94% + Tebuconazole 20.8% causing complete inhibition (100 %) at 100, 300 and 500 mg l, followed by Penconazole causing 100 % inhibition at 300 and 500 mg l; moreover, it caused strong inhibition of 90.17 % at 100 mg l. Both fungicides proved to be the most effective expressing strong inhibition potency of 93.75 % even at the lowest concentration of 20 mg l after 5 days of fungal incubation, although the inhibitory efficacy decreased slightly over time after 10 days of incubation. Mancozeb was the third effective fungicide causing strong mycelial inhibition of (41.91, 75.24 and 84.21 %) at 100, 300 and 500 mg l, respectively. The least mycelial growth inhibition was observed with Copper oxychloride (8.77 %) followed by Carbendazim (21.05 %) at maximum concentration of 500 mg l. For the best of our knowledge, this is the first report of A. alternata as the fungal causal agent of potato brown spot in Afghanistan.

https://nrmj.journals.ekb.eg/article_149383_6de7497ffb6fb2afed4b9b24197d414b.pdf

Evaluation of in vitro antifungal potential of several fungicides against Alternaria alternata (Fr.) Keissler, the causal agent of potato brown spot in Afghanistan

The antagonistic activity of Aspergillus piperis against Fusarium oxysporum f. sp. fabae (FOF) and Sclerotinia sclerotiorum were examined and showed multiple signs of hyphal interactions. Microscopic examination of contact regions among A. piperis and each pathogen revealed distinct enzymatic lysis of pathogenic hyphal cell walls. Therefore, it is important to estimate the lytic enzyme activity of A. piperis. Extracellular lytic enzymes are important offensive forces for A. piperis as a biological control agent. Chitinase, phospholipase, and protease recorded relatively high activity from a culture age of 10 days (82.3, 42.4, and 6.2 U/ml, respectively). Enzymatic persistence was measured at room temperature, recording relatively long periods, saving 54%, 46%, and 21% of their activity, respectively. The cytotoxicity of the crude culture filtrate of A. piperis was examined in MCF7 and WI38 human cell lines. The cell viability (IC50) value of the fungal filtrate was estimated after 24 h and 48 h. The results revealed that IC50 values against the MCF7 cell line were inoperative after 24 h and were recorded 80 μg/ml after 48 h. In contrast, IC50 values against the WI38 cell line were 85.69 and 69.8 μg/ml after 24 and 48 h, respectively.

Lytic Enzymes of Aspergillus piperis as a Tool for Attacking Some Phytopathogenic Fungi In vitro with Special Reference to its Cytotoxicity

Field pea (Pisum sativum L.) is an important pulse crop grown throughout the world including India. The crop plays an important role in human diet providing higher amount of proteins, minerals and essential amino acids particularly lysine (Nawab, et al., 2008) and improving soil health in terms of fertility and sustainability of the cropping patterns. India is one of the largest field pea producers in the world, stands at the fifth place next to France (Javed, et al., 2002) and contributing of area (0.76 m ha), production (0.84 m t) with productivity (1.1 t/ha), respectively (Gowda 2015). The pea cultivation is ravaged by several fungal diseases including ascochyta blight (Ascochyta pisi), powdery mildew (Eryisphe pisi), downy mildew (Peronospora viciae f. sp. pisi), septoria blight (Septoria pisi), and white mold (Sclerotinia sclerotiorum), common seed rot (Rhizoctonia solani), seedling damping-off diseases (Pythium spp.) and Common root rots include Fusarium root rot (Fusarium solani f. sp. pisi), Aphanomyces root rot (Aphanomyces euteiches), and Fusarium wilt (Fusarium oxysporum f. sp. pisi) (Kraft and Pfleger, 2001; McGee, 2012). Among all fungal pathogen, Sclerotinia sclerotiorum, causing white mould of pea known to be most devastating, cosmopolitan and necrotrophic International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 7 (2017) pp. 2150-2154 Journal homepage: http://www.ijcmas.com

Screening of Pea Accessions for Resistance against White Rot of Pea Caused by Sclerotinia sclerotiorum (Lib.) de Bary

The present experiment was conducted to test the efficacy of fungicides, bio-control agents and plant extracts in vitro against Alternaria solani causing early blight of tomato. Seven fungicides viz., four systemic (Propiconazole, Azoxystrobin, Thiophanate methyl and Carbendazim) and three non-systemic (Mancozeb, Captan and Zineb) at four concentrations i.e. 50, 100, 150 and 200 ppm and seven plant extracts viz., Datura strumarium (Jimson weed), Allium sativum (Garlic), Azadirachta indica ( Neem ), Zingiber officinale (Ginger), Ocimum sanctum ( Tulsi ), Calotropis gigantea (Aak) and Eucalyptus chamadulonsis (Eucalyptus) also at four concentrations i.e. 5, 10, 15 and 20 per cent were evaluated through poison food technique. Seven bio-control agents viz., Trichoderma harzianum, T. viride, T. koningii, T. hamatum, T. atroviride, Aspergillus niger and A. flavus were also evaluated in this study through dual culture technique. Among the systemic fungicides, Propiconazole was proved to be highly effective and recorded cent per cent inhibition at their all concentrations while among the non-systemic, Mancozeb was proved to be effective at their all concentrations but recorded 100 per cent inhibition only at their higher concentration i.e. 400 ppm. Among different plant extracts used, Azadirachta indica ( Neem ) was significantly inhibit the mycelial growth of pathogen at all concentrations followed by Datura strumarium (Jimson weed) and Calotropis gigantea (Aak). Of all bio-control agents, highest inhibition of radial growth of test fungus was recorded in Trichoderma harzianum (80.37%) followed by T. viride (71.48%) and T. koningii (77.41 %). However, T. hamatum (27.41%) was least effective in this study.

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In vitro evaluation of fungicides, bio-control agents and plant extracts against early blight of tomato caused by Alternaria solani (Ellis and Martin) Jones and Grout

Genetic diversity and future prospects in Withania somnifera (L.) Dunal: an assessment based on quantitative traits in different accessions of Ashwagandha

The symbiotic plant–microbe interaction is a remarkable phenomenon observed in the rhizosphere that determines the sustainability of the ecosystem by improving plant health and soil properties. In this beneficial relationship, the host plant provides necessary and other basic life supporting materials to the fungi, whereas fungi in-return helps to available essential minerals and life supporting nutrients especially P2O5 to the host plant. Instead of providing major nutrients, Mycorrhiza also acts as bio protectants against pathogens and toxic stresses during biological interaction. But nowadays, due to the changing environment and indiscriminate use of pesticides, pose a great menace to the existence of mycorrhizal species. Therefore, it is required to spread awareness in relation to save mycorrhizal fungi from extinction.

Mycorrhizal Association: A Mutualistic Relationship for Growth Enhancement and Disease Suppression in Crop Plants

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Vaibhav Pratap Singh

Papers

Screening of Pea Accessions for Resistance against White Rot of Pea Caused by Sclerotinia sclerotiorum (Lib.) de Bary

In vitro evaluation of fungicides, bio-control agents and plant extracts against early blight of tomato caused by Alternaria solani (Ellis and Martin) Jones and Grout

Genetic diversity and future prospects in Withania somnifera (L.) Dunal: an assessment based on quantitative traits in different accessions of Ashwagandha

Mycorrhizal Association: A Mutualistic Relationship for Growth Enhancement and Disease Suppression in Crop Plants

Cultural and morphological variations among the isolates of Sclerotinia sclerotiorum (Lib.) de Bary causing Sclerotinia stem rot