• Mycobiology
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• v.42 no.1
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• pp.66-72
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• 2014

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

• Mycobiology
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• v.41 no.1
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• pp.47-55
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• 2013

Rhizoctonia solani, Fusarium solani, F. oxysporum, and Macrophomina phaseolina were found to be associated with root rott and wilt symptoms of faba bean plants collected from different fieldes in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenicity tests. Biocontrol agents (Trichoderma viride and Bacillus megaterium) and chemical inducers (salicylic acid [SA] and hydrogen peroxide) individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promoting of faba bean plants in vitro and in vivo. Both antagonistic biocontrol agents and chemical inducers either individually or in combination inhibited growth of the tested pathogenic fungi. Biocontrol agents combined with chemical inducers recorded the highest inhibited growth especially in case SA + T. viride and SA + B. megaterium. Under green house and field conditions, all treatments significantly reduced damping-off and root rot/wilt severity and increased of survival plants. Also, these treatments increased fresh and weights of the survival plants in pots compared with control. The combination between biocontrol agents and chemical inducers were more effective than used of them individually and SA + T. viride was the best treatment in this respect. Also, under field conditions, all these treatments significantly increased growth parameters (plant height and number of branches per plant) and yield components (number of pods per plant and number of seeds per plant, weight of 100 seeds and total yield per feddan) and protein content in both seasons (2010~2011 and 2011~2012). Faba bean seeds soaked in SA + T. viride and SA + B. megaterium were recorded the highest growth parameters and yield components. Generally, the combination between biocontrol agents and chemical inducers recorded the best results for controlling damping-off and root rot/wilt diseases in greenhouse and field with addition improved plant growth and increased yield components in field.

• Mycobiology
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• v.42 no.4
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• pp.376-384
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• 2014

Roselle (Hibiscus sabdariffa L.) is one of the most important medicinal crops in many parts of the world. In this study, the effects of microelements, antioxidants, and bioagents on Fusarium oxysporum, F. solani, and Macrophomina phaseolina, the causal pathogens of root rot and wilt diseases in roselle, were examined under field conditions. Preliminary studies were carried out in vitro in order to select the most effective members to be used in field control trials. Our results showed that microelements (copper and manganese), antioxidants (salicylic acid, ascorbic acid, and EDTA), a fungicide (Dithane M45) and biological control agents (Trichoderma harzianum and Bacillus subtilis) were significantly reduced the linear growth of the causal pathogens. Additionally, application of the previous microelements, antioxidants, a fungicide and biological control agents significantly reduced disease incidence of root rot and wilt diseases under field conditions. Copper, salicylic acid, and T. harzianum showed the best results in this respect. In conclusion, microelements, antioxidants, and biocontrol agents could be used as alternative strategies to fungicides for controlling root rot and wilt diseases in roselle.

• Korean Journal Plant Pathology
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• v.14 no.2
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• pp.103-108
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• 1998

A Pythium species was isolated from roots of lisianthus (Eustoma grandiflorum) showing wilt symptoms and reduced growth in a greenhouse at Ichon, Kyonggi-do in 1997. The Pythium species was identified as Pythium spinosum Sawada based on various mycological characteristics. The isolate was strongly pathogenic when inoculated to root of lisianthus plants in pots. The diseased plants showed typical symptoms of root and crown rot, resulting in reduced growth of roots and shoots, and consequently wilting of the above ground part of plants.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.676-681
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• 1998

Disease incidence of Codonopsis lanceolata was surveyed at the major cultivating fields in Chonbuk province in 1996 to 1997. The main diseases of Codonopsis lanceolata were ovserved as leaf spot caused by Septoria codonopsis, anthracnose by Glomerella cingulata, brown leaf spot by Cercospora sp., rust by Coleosporium koreanum, powdery mildew by Erysiphe sp., Fusarium wilt caused by Fusarium oxyporum, and white root rot by Sclerotium rolfsii. Anthracnose, leaf spot and brown leaf spot occurred severely on leaves from early July to late August. They were caused early fallen leaves. Fusarium wilt and white root rot occurred severely on stem and below the soil line in late August. They resulted in withering to death or chlorosis and fallen of leaves. Disease incidence of Codonopsis lanceolata was also substantially different in occurrence with a method of cultivation in late growth stage. Fusarium wilt and white root rot were more severe with a method of no support cultivation than those with a method of support cultivation with a stick. Fusarium wilt occurred 48.8% in a method of no support cultivation but 3.1% in a method of support cultivation with a stick. And white root rot occurred 18.9% in a method of no support cultivation but 0.3% in a method of no support cultivation with a stick. Thus, it proved that soil-borne diseases could be controlled support cultivation with a stick.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.58-60
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• 1999

Cultivation of a native wild vegetable, Ligularia fischeri, is hampered by Phytophthora sp. Infected plants showed wilt and eventual death due to rots on the root and basal portion. Eight isolates collected were all identified as P. drechsleri based on their mycological characteristics. The fungi showed relatively strong pathogenicity to L. Fischeri, mild to Aster scaber and Codonoposis lanceolata, and none to Circium setidens and Pimpinella brachycarpa. This is the first report of Phytophthora root rot on wild vegetables in Korea.

• The Korean Journal of Mycology
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• v.29 no.2
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• pp.127-130
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• 2001

A Pythium species was isolated from roots of Codonopsis pilosula showing wilt symptoms in a field at Yonchon, Kyonggido of Korea from late June to early August in 2000. The Pythium species was identified as Pythium myriotylum Drechsler based on various mycological characteristics. The isolate was strongly pathogenic when inoculated to root of C. pilosula plants in pot. The inoculated plants showed typical symptoms of root rot, resulting in reduced growth of root and consequently wilting of above ground part of plants. Pythium root rot of C. pilosula caused by P. myriotylum has not been reported previously in Korea.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.363.2-363
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• 2001

• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.33-41
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• 2005

Above 130 accessions of pepper consisting of 50 introductions from Mexico and Nepal, and resistant and susceptible controls were tested for resistance to bacterial wilt and to Phytophthora root rot at seedling stage by artificial inoculation. Aa the results, KC897, KC939, KC936 were newly found resistant to bacterial wilt in addition to already known resistance sources such as KC126, KC350, KC351, KC353. No new sources of resistance to Phytophthora root rot were found among the introductions from Mexico and Nepal.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.151-158
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• 1997

Tomato (lycopersicon esculentum Mill.‘Sunroad’) seedlings grafted onto the four different rootstocks, ‘Anchor-T’, ‘Kagemushia’, ‘Joint’ and ‘Vulcan’, and fed with different amount of nitrogen were investigated for their susceptibility to the root rot Fusarium wilt (Fusarium oxysporum Schl. f. sp. lycopersici Snyder et Hansen, race J$_3$) disease, plant growth, and fruit quality. The flowering of the first flower cluster was promoted in grafted plants (GP) as compared to non-grafted (NG) ones. The plant height was increased by the grafting, and the growth and stem diameter were enhanced with increased nitrogen levels. Grafted plants were little affected by the Fusarium wilt disease except ‘Anchor-T’rootstock (64.7％ infection). The rate of malformed, underdeveloped, and gray-mold infected fruits were reduced in the grafted plants regardless of the rootstocks. Soluble solid content, sugars, ascorbic acids and organic acids did not show any difference between grafted and non grafted plants, but ascorbic acid tends to be reduced in the high nitrogen treatment. Content of N, Ca and Mg in leaves were greatly increased in the GP grown with high nitrogen level (30kg.㏊$^{-1}$ ).