• International Journal of Industrial Entomology and Biomaterials
• /
• 제16권2호
• /
• pp.49-56
• /
• 2008

A preliminary survey on the incidence and intensity of root disease complex (association of Meloidogyne incognita and root rot pathogens) was carried out in the sericultural areas of Karnataka. A total of 280 mulberry gardens were surveyed in 14 districts of Karnataka belonging to different types of soil (red sandy, red loamy and black cotton), farming systems (irrigated and rainfed), varieties (V-1, K-2, Local and S-13) and age of the plants (0-5, 5-10 and 10-15 years). It was observed that the association of M. incognita with Botryodiplodia theobromae and Fusarium solani causes the root disease complex in mulberry. Of the 280 gardens visited, 94 were infested with the disease complex and incidence was recorded as 33.6%. The higher intensity of root disease complex was observed when the root system had more than 100 galls/plant with infection of mixed population of B. theobromae and F. solani in sandy soil under irrigated farming. The 5-10 years old mulberry plantation with V-I variety was found to be most susceptible to root disease complex. Districts like Mysore, Kolar, Mandya, Tumkur, Chitradurga and Bangalore were observed as sensitive areas. Further, the wounds caused by M. incognita in mulberry roots favour the easy entry of root rot pathogens, which increased the severity of the disease very fast.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제15권2호
• /
• pp.101-106
• /
• 2007

During mulberry cultivation, root disease complex caused by the association of root knot nematode (Meloidogyne incognita) with root rot pathogens like Fusarium solani and Botryodiplodia theobromae poses serious loss in leaf production. Therefore, an attempt was made to assess the efficacy of eight pesticides (Metayalaxyl+Mancozeb, Thiophanate methyl, Mancozeb, Bitertanol, Phenomiphos, Phorate, Thionazin & Carbofuran) and two growth hormones (Salicylic acid and Indole 3 acetic acid) at 0.1 and 0.2% concentrations under in vitro conditions against nematode (hatching of eggs and mortality of larvae) and root rot pathogens (poisoned food technique) for short listing the treatments to develop an IDM strategy. Results revealed that among the pesticides and growth hormones, Carbofuran followed by Salicylic acid were found to be effective at 0.2% concentration against both nematode and pathogenic fungi. Both the chemicals inhibited the hatching of nematode eggs by 83.5-78.9% and 80-76% larval mortality over the control and reduced the mycelial growth of both the pathogenic fungi to an extent of 75.5-77.8%. Though Mancozeb inhibited both the pathogenic fungi strongly (77-80%), it did not show any effectiveness against nematode. The rest of the chemicals were found either moderately or poorly effective in reducing the growth of pathogenic fungi, hatching of nematode eggs and enhancing the mortality of larvae. The two effective chemicals viz., Carbofuran and Salicylic acid, which rated as strong inhibitors against both nematode and pathogenic fungi, can be exploited in developing an IDM package as one of the component for better management of root disease complex in mulberry.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제14권1호
• /
• pp.57-61
• /
• 2007

For developing an integrated eco-friendly package against root knot disease complex of mulberry caused by the association of Meloidogyne incognita with Fusarium solani and F. oxysporum causing serious loss in terms of leaf yield and quality during cultivation, twenty botanical extracts at 5, 10 & 20% concentrations were screened under in vitro conditions. Among the extracts, Allium sativum followed by Lasownia inermis were found to be effective at 20% concentration against both the virulent fungi and nematode. Both the extracts reduced the mycelial growth of virulent fungi to an extent of 76-100%, inhibited the hatching of nematode eggs by 80-90% and 76-85% larval mortality over the control. The other extracts were found either moderately or poorly effective in reducing the growth of fungi, hatching of nematode eggs and enhancing the mortality of larvae. The two effective botanical extracts, which rated as strong inhibitors against both nematode and virulent fungi, can be utilized in developing an integrated ecofriendly technology for better management of root knot disease complex in mulberry.

• Journal of Ginseng Research
• /
• 제44권3호
• /
• pp.506-518
• /
• 2020

Background: Red-skin root of Asian ginseng (Panax ginseng) significantly reduces the quality and limits the production of ginseng in China. The disease has long been thought to be a noninfectious physiological disease, except one report that proved it was an infectious disease. However, the causal agents have not been successfully determined. In the present study, we were to reveal the pathogens that cause red-skin disease. Methods: Ginseng roots with red-skin root symptoms were collected from commercial fields in Northeast China. Fungi were isolated from the lesion and identified based on morphological characters along with multilocus sequence analyses on internal transcription spacer, β-tubulin (tub2), histone H3 (his3), and translation elongation factor 1α (tef-1α). Pathogens were confirmed by inoculating the isolates in ginseng roots. Results: A total of 230 isolates were obtained from 209 disease samples. These isolates were classified into 12 species, including Dactylonectria sp., D. hordeicola, Fusarium acuminatum, F. avenaceum, F. solani, F. torulosum, Ilyonectria mors-panacis, I. robusta, Rhexocercosporidium panacis, and three novel species I. changbaiensis, I. communis, and I. qitaiheensis. Among them, I. communis, I. robusta, and F. solani had the highest isolation frequencies, being 36.1%, 20.9%, and 23.9%, respectively. All these species isolated were pathogenic to ginseng roots and caused red-skin root disease under appropriate condition. Conclusion: Fungal complex is the causal agent of red-skin root in P. ginseng.

• Journal of Ginseng Research
• /
• 제42권1호
• /
• pp.9-15
• /
• 2018

Cylindrocarpon destructans/Ilyonectria radicicola is thought to cause both rusty symptom and root-rot disease of American and Korean ginseng. Root-rot disease poses a more serious threat to ginseng roots than rusty symptoms, which we argue result from the plant defense response to pathogen attack. Therefore, strains causing rotten root are characterized as more aggressive than strains causing rusty symptoms. In this review, we state 1- the molecular evidence indicating that the root-rot causing strains are genetically distinct considering them as a separate species of Ilyonectria, namely I. mors-panacis and 2- the physiological and biochemical differences between the weakly and highly aggressive species as well as those between rusty and rotten ginseng plants. Eventually, we postulated that rusty symptom occurs on ginseng roots due to incompatible interactions with the weakly aggressive species of Ilyonectria, by the established iron-phenolic compound complexes while root-rot is developed by I. morspanacis infection due to the production of high quantities of hydrolytic and oxidative fungal enzymes which destroy the plant defensive barriers, in parallel with the pathogen growth stimulation by utilizing the available iron. Furthermore, we highlight future areas for study that will help elucidate the complete mechanism of root-rot disease development.

• The Plant Pathology Journal
• /
• 제28권3호
• /
• pp.311-316
• /
• 2012

Fusarium root disease can be a serious problem in forest and conservation nurseries in the western United States. Fusarium inoculum is commonly found in most container and bareroot nurseries on healthy and diseased seedlings, in nursery soils, and on conifer seeds. Fusarium spp. within the F. oxysporum species complex have been recognized as pathogens for more than a century, but attempts to distinguish virulence by correlating morphological characteristics with results of pathogenicity tests were unsuccessful. Recent molecular characterization and pathogenicity tests, however, revealed that selected isolates of F. oxysporum are benign on Douglas-fir (Pseudotsuga menziesii) seedlings. Other morphologically indistinguishable isolates, which can be virulent, were identified as F. commune, a recently described species. In a replicated greenhouse study, inoculating Douglas-fir seedlings with one isolate of F. oxysporum prevented expression of disease caused by a virulent isolate of F. commune. Moreover, seedling survival and growth was unaffected by the presence of the F. oxysporum isolate, and this isolate yielded better biological control than a commercial formulation of Bacillus subtilis. These results demonstrate that an isolate of nonpathogenic F. oxysporum can effectively reduce Fusarium root disease of Douglas-fir caused by F. commune under nursery settings, and this biological control approach has potential for further development.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제7권2호
• /
• pp.93-106
• /
• 2003

Soilborne diseases pose a serious problem for mulberry cultivation during nursery plantation and established gardens, which cause severe loss in revenue generation of mulberry growers as compared to foliar diseases. Various soilborne diseases affect mulberry. Among them, root knot and root rot affect the established plantation resulting in severe loss in leaf yield apart from deterioration in leaf quality, which is a pre-requisite in successful sericulture to get the good quality of cocoons. Besides, stem-canker, cutting rot, collar rot and die-back, affect the initial establishment and survivability of mulberry plantation in nursery. The problem is difficult to handle, due to the complex nature of the diseases and also involvement of various biotic and abiotic factors. This is compounded by the occurrence of disease complex (especially nematode ＋ soilborne pathogenic microbes) in established mulberry gardens, which facilitates quick spread of the disease and enhance the plant mortality, resulting substantial loss in leaf yield. Therefore, prevention and timely control measures need to be taken up to protect the mulberry plants from different soilborne plant pathogens. In this review article, symptomatology, epidemiology, disease cycle and control measures of soilborne diseases of mulberry are discussed.

• Journal of Applied Biological Chemistry
• /
• 제48권2호
• /
• pp.79-83
• /
• 2005

While screening for nematicidal activity of bacterial origins, various pseudomonads strains were inhabited in tomato rhizosphere. One isolate designated as $PE_{10}$ was selected for studies on nematicidal properties and plant growth-promoting (PGP) activity and was identified as Pseudomonas aeruginosa based on morphological features, biochemical and physiological tests, and carbohydrate utilization. To investigate nematicidal activity, Meloidogyne incognita juvenile mortality was determined using $PE_{10}$ culture filtrate. Inhibition of strain $PE_{10}$ against Fusarium oxysporum was observed using dual culture technique. Strain $PE_{10}$ showed good siderophore activity, HCN and IAA production abilities, and growth and development enhancement of tomato.

• 한국균학회지
• /
• 제45권2호
• /
• pp.132-138
• /
• 2017

작약에서 분리된 Cylindrocarpon destructans KACC44663 균주의 인삼에 대한 병원성 여부를 밝혀내고자 병원성 검정을 실시하였고 새로운 분류체계에 따른 균의 재분류를 위해 계통학적 유연관계를 분석하였다. 작약으로부터 분리된 KACC44663 균주가 인삼에 병을 일으키는 것을 확인하였고, 새로운 분류체계에 의해 I. radicicola species complex 내 위치하는 Ilyonectria robusta로 동정하였다. 이는 국내에서 타 기주로부터 분리된 병원균이 인삼에 뿌리썩음병을 일으키는 것을 증명한 첫 사례이다.

• 식물병연구
• /
• 제19권1호
• /
• pp.25-30
• /
• 2013

국내에서 시판되고 있는 토마토 36품종을 이용하여 국내 시설재배지에서 가장 많이 분포하고 있는 두 종의 뿌리혹선충, Meloidogyne arenaria와 M. incognita에 대한 저항성을 검정하였다. 방울토마토 중에서는 '텐텐', '캐딜락', '큐티', '스위트', '뽀또', '리코핀-9' 등 6품종, 완숙토마토 중에서 '러브리240', '도테랑다이아', '큐피랑', '도테랑마스터', '슈퍼도태랑', '도태랑시즌', '마이로꾸', '호용' 등 8품종, 대목은 '스페셜', '파이팅', '마그네트' 등 3품종이 두 종류의 뿌리혹선충에 모두 강한 저항성이었다.