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Thread: Projek Cinta: Bacteria Wilt of Ginger

   
   
       
  1. #1
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    Projek Cinta: Bacteria Wilt of Ginger

    Bacteria Wilt of Edible Ginger:


    Management:

    Integrated Management Practices for Bacterial Wilt of Edible Ginger

    Some of these practices require sufficient planning and may have significant costs in money, supplies, time and labor.


    • Site selection. The site should be well-drained and having no previous history of ginger cultivation. Do not plant downslope from another ginger field, as the runoff rainwater water can carry the pathogen. Test the soil at a field site for the pathogen before planting by PCR or a bioassay. Select a site with consistent rainfall throughout the growing season, and with a drier period at the end of the growing season (before and during harvest). If a site has excessive rainfall, the waterlogged soil may foster soil-borne diseases such as root rot and bacterial wilt. Choose a site with gently sloping land to improve soil drainage during the rainy months.


    • Planting. Avoid planting during very wet weather, as this promotes dispersal of the pathogen within fields in draining water and on muddy boots and tools.


    • Site preparation. Hill the planting rows to promote aeration of roots and adequate soil drainage. Use clean, pathogen-free equipment. Prepare soil plowing and harrowing so that the site and soils drain well after rainfall.






    • Limit site traffic. Strictly limit external traffic and unnecessary visitors into ginger fields, as the pathogen can be attached to soil adhering to truck tires or boots. Do not bring tools to the farm that have any soil attached, as soil can harbor R. solanacearum.


    • Composting. Specify types of compost, time interval


    • Organic soil amendments. Mulches and composts promote microbial activity that may suppress R. solanacearum by competition and/or antibiosis.


    • Crop rotation. Rotate ginger with crops that are not hosts of the bacterial wilt pathogen, R. solanacearum. Such root/tuber crops include sweetpotato and taro. Insert more comprehensive list here.


    • Soil drainage. Ensure adequate soil drainage and diversion ditches to prevent the runoff of infected water sources into fields that are down slope from an infected field.


    • Intercropping. Intercrop ginger with crops that are not hosts of the bacterial wilt pathogen, R. solanacearum. Such root/tuber crops include sweetpotato and taro. Insert more comprehensive list here.


    • Hot water treatment consisting of exposing seeds to a constant 50°C temperature for 10 minutes is effective in controlling nematodes. However, hot water treatments are not effective for disease organisms such as R. solanacearum that are already present inside the rhizome.


    • Biofumigation is the use of essential oils to kill or suppress the pathogen. Such oils are a natural component of certain green manures crops such as mint, palmarosa, and lemongrass. When these plants are turned or plowed into soils several months before planting, they decompose and release the essential oils which are toxic to the pathogenic bacteria. Plant essential oils have potential to control bacterial wilt by eliminating the disease-causing bacteria in field soil. The results of a study by Paret (2010, see References at bottom of this page) show that palmarosa and lemongrass oils were effective in significantly reducing the bacterial wilt pathogen in both laboratory and greenhouse studies. In addition, "none of the essential oil treatments reduced the growth or yield of the edible ginger test plants. Palmarosa (Cymbopogon martini), lemongrass (C. citratus) and eucalyptus (Eucalyptus globulus) oils were investigated for their effects on Ralstonia solanacearum race 4, and their potential use as bio-fumigants for treating pathogen- infested edible ginger (Zingiber officinale R.) fields. Three concentrations of the oils (0.04, 0.07 and 0.14 % v/v) were evaluated by culture amendment assay, epifluorescence microscopy, and pot studies. Culture amendment assay indicated complete inhibition of growth of the bacterium on the medium with palmarosa and lemongrass oils at 0.07 % and above. At 0.04 %, both oils significantly reduced the growth of the bacterium compared to the control. Eucalyptus oil at all concentrations did not reduce the growth of the bacterium. Epifluorescence microscopic observations showed 95-100 % cell death when treated with palmarosa and lemongrass oils at all concentrations and eucalyptus oil at 0.14 % in a direct contact assay indicating its bactericidal effect. Eucalyptus oil treatments at 0.04 and 0.07 % had bacteriostatic effects on cells. The pathogen was not detected in R. solanacearum- infested potting medium after treatment with palmarosa and lemongrass oils at 0.07 % and above in any of the experiments. None of the treatments reduced the growth or yield of edible ginger."


    • Biological control. Biological control of bacterial wilt of edible ginger currently is not a viable management practice. More research and development in this area are needed.


    • Control other pests that create injuries in ginger plants, such as the lesser corn stalk borer (Elasmopalpus lignosellus). The injuries are infection courts for R. solanaearum.


    • Perform on-time harvest, which minimizes crop exposure to the pathogen.




    Videos:





    Videos about disease symptoms and management
    py

  2. #2
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    Symptoms:

    Read our new publication: "Bacterial Wilt of Edible Ginger in Hawaii" (Oct 2013)

    Symptoms of bacterial wilt of ginger include:


    1. "Green wilt" is the diagnostic symptom for the disease. This symptom occurs early in the disease cycle and precedes leaf yellowing. Green ginger leaves roll and curl due to the water stress caused by the bacteria that block the vascular systems of the ginger stems.
    2. Leaf yellowing and necrosis. Leaves of infected plants invariably turn yellow and then brown. The yellowing should not be confused with another disease of ginger causing similar symptoms, Fusarium yellows. Note: Plants infected by the fungus, Fusarium oxysporum f. sp. zingiberi, do not wilt rapidly, as in bacterial wilt. Instead, infected ginger plants are stunted and yellowed. The lower leaves dry out over an extended period of time. Compare the symptoms of bacterial wilt and Fusarium yellows in this publication: C2-62.pdf.
    3. Plant stunting. Diseased plants grow poorly and may be stunted.
    4. Plant decline and death. Diseased plants can decline rapidly and die before harvest.
    5. Rotten rhizomes, often discolored.
    6. Water-soaked appearance of infected rhizomes and stem vasculature.
    7. Discoloration of vascular tissues
    8. Soft rots, caused by Erwinia spp.



    E. E. Trujillo (1964, http://cms.ctahr.hawaii.edu/Portals/43/C2-62.pdf) accurately described the disease symptoms progress of bacterial wilt of ginger:

    "The first symptoms of wilt are a slight yellowing and wilting of the lower leaves. The wilt progresses upward, affecting the younger leaves, followed by a complete yellowing and browning of the entire shoot. Under conditions favorable for disease development, the entire shoot becomes flaccid and wilts with little or no visible yellowing. However, the plant dries very rapidly and the foliage becomes yellow-brown in 3 to 4 days. Young succulent shoots frequently become soft and completely rotted and these diseased shoots break off easily from the underground rhizome at the soil line. The underground parts are also completely infected. Grayish-brown discoloration of the rhizomes may be localized if the disease is at an early stage of infection, or discoloration may be general if the disease is in an advanced stage. A water-soaked appearance of the central part of the rhizome is common. In advanced infections, the entire rhizome becomes soft and rots. Bacterial wilt of ginger can be distinguished from other rhizome rots of ginger by the condition of the rhizome and the foliage. A better diagnostic feature is the extensive bacterial ooze that shows as slimy, creamy exudate on the surface of a cut made in the rhizome or on the above-ground stem of an infected plant."




    Slideshow (above), with captions


    Do you want photos of bacterial wilt of edible ginger? Here is a gallery of copyright-free photographs of bacterial wilt disease symptoms for free viewing and download: http://flic.kr/s/aHsjDNuVZN


    Signs of bacterial wilt include:

    1. bacterial streaming and
    2. bacterial ooze from infected tissues, especially from infected rhizomes.



    Signs of bacterial wilt of edible ginger
    Left:
    Bacterial streaming from an infected ginger rhizome suspended in water. The streaming begins only a few minutes after placing the cut rhizome in water. This is a reliable assay for bacterial wilt. Right: Milky, bacterial ooze forming the cut surface of a discolored, infected ginger rhizome. The bacterial colonies may take one or two days to form, and form more rapidly in a humid environment.

    One may use either of these two signs of the pathogen to diagnose bacterial wilt of ginger caused by
    Ralstonia solanacearum
    .
    py

  3. #3
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    Pathogen
    The ginger bacterial wilt pathogen is the soil- and water-borne bacterium, Ralstonia solanacearum race 4.


    Ralstonia solanacearum race 4 in culture.
    Photograph: Donald Gardner (1999) from www.hear.org (http://www.hear.org/pph/images/26_036.htm)

    Synonyms and nomenclature: Pseudomonas solanacearum (Smith, 1896) Smith 1914; Burkholderia solanacearum (Smith, 1896) Yabuuchi et al. 1992; and many others. For more information about the taxonomy of the pathogen, visit this page: link.

    Dispersal:
    Ralstonia solancearum spreads by infested soil adhering to hands, boots, tools, vehicle tires and field equipment, water from irrigation or rainfall, and infected ginger rhizomes (Janse 1996).

    Infection:
    Ralstonia solanacearum infects ginger roots and rhizomes through openings where lateral roots emerge or wounds caused by handling, parasitic insects or root-knot nematodes (Swanson et al. 2005).

    Survival:
    The pathogen survives in soils within infected plant debris in soils and as free bacteria.

    Geographic distribution:
    The pathogen is widely distributed in many locations where ginger has been grown previously in Hawaii.

    Crop losses:
    Crop loss can be complete in heavily infested soils.

    Use as a biological control agent for kahili ginger?
    No. Although the Wikipedia site (http://en.wikipedia.org/wiki/Ralstonia_solanacearum) indicates thatR. solanacearum race 4 could be used as a biological control agent for kahili ginger, this is not true. Even if the pathogen could cause significant disease on kahili ginger, applying it upslope of ginger fileds in Hawaii would pose significant risk to the ginger crops.

    Host range: Ralstonia solanacearum race 4 is restricted to edible ginger (Zingiber officinale)
    py

  4. #4
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    Diagnosis

    Diagnosis. Here is an outline presented as an overview of wilt diagnosis for ginger. More information is included on the linked pages below.

    1. Signs

    • bacterial ooze from infected tissues
    • bacterial streaming from infected tissues

    2. Symptoms

    3. Serological tests


    4. DNA tests


    5. Bioassay

    6. Testing services


    Comparison of various testing methods for diagnosis of bacterial wilt of edible ginger:
    Diagnostic
    method
    Time
    required
    Reliability Cost
    Signs Minutes High Low
    Symptoms Minutes Low Low
    Serological tests Minutes High Moderate
    DNA tests Hours High High (equipment, skill)
    Bioassay Days Moderate Moderate (pots, medium,
    Testing services Days High Moderate



    Pathogen detection. The bacterial wilt pathogen can be detected using a number of different laboratory methods and from several different sources:

    1. Soil
    2. Water
    3. Infected plant tissue




    Video: Detection of Ralstonia solanacearum race 4 using PCR (Polymerase Chain Reaction)




    py

  5. #5
    Join Date
    Oct 2008
    Posts
    13,399
    Diagnosis. Here is an outline presented as an overview of wilt diagnosis for ginger. More information is included on the linked pages below.

    1. Signs

    • bacterial ooze from infected tissues
    • bacterial streaming from infected tissues

    2. Symptoms

    3. Serological tests


    4. DNA tests


    5. Bioassay

    6. Testing services


    Comparison of various testing methods for diagnosis of bacterial wilt of edible ginger:
    Diagnostic
    method
    Time
    required
    Reliability Cost
    Signs Minutes High Low
    Symptoms Minutes Low Low
    Serological tests Minutes High Moderate
    DNA tests Hours High High (equipment, skill)
    Bioassay Days Moderate Moderate (pots, medium,
    Testing services Days High Moderate



    Pathogen detection. The bacterial wilt pathogen can be detected using a number of different laboratory methods and from several different sources:

    1. Soil
    2. Water
    3. Infected plant tissue



    py

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