Search Legislation

Council Directive 93/85/EECShow full title

Council Directive 93/85/EEC of 4 October 1993 on the control of potato ring rot

 Help about what version

What Version

More Resources

Close

This is a legislation item that originated from the EU

After exit day there will be three versions of this legislation to consult for different purposes. The legislation.gov.uk version is the version that applies in the UK. The EU Version currently on EUR-lex is the version that currently applies in the EU i.e you may need this if you operate a business in the EU.

The web archive version is the official version of this legislation item as it stood on exit day before being published to legislation.gov.uk and any subsequent UK changes and effects applied. The web archive also captured associated case law and other language formats from EUR-Lex.

Status:

This is the original version (as it was originally adopted).

7. Isolation of C. sepedonicum

Diagnosis can only be confirmed if C. sepedonicum is isolated and so identified (8). Although C. sepedonicum is a fastidious organism, it can be isolated from symptomatic tissue. However, it may be outgrown by rapidly growing saprophytic bacteria and, therefore, isolations directly from the tuber tissue pellet (3.3) are not recommended. Eggplants provide an excellent selective enrichment medium for the growth of C. sepedonicum and also provide an excellent confirmatory host test.

Isolations should be made from all symptomatic potato tubers and eggplants (4, 6). Maceration of eggplant stems when necessary should be carried out as in 3. and 6.9.

7.1.Streak suspensions on to one of the following media: (formulae are given in Appendix 6):

nutrient dextrose agar (for subculture only),

yeast peptone glucose agar,

nutrient yeast dextrose agar,

yeast extract mineral salts agar.

Incubate at 21 oC for up to 20 days.

C. sepedonicum is slow-growing, usually producing pin-point, cream, domed colonies within 10 days.

Re-streak to establish purity.

Growth rates are improved with subculture. Typical colonies are creamy-white or ivory, rounded, smooth, raised, convex-domed, mucoid-fluidal, with entire edges and usually 1 to 3 mm in diameter.

Identification

Many Gram positive coryneform bacteria, with colonial characters similar to those of C. sepedonicum, may be isolated from healthy or diseased potatoes and eggplants. In this context C. sepedonicum must be identified by the following tests:

IF test (5.1),

eggplant test,

nutrition and physiological tests (Appendix 7),

  • oxidation/fermentation test (O/F),

  • oxidase test,

  • growth at 37oC,

  • urease production,

  • aesculin hydrolysis,

  • starch hydrolysis,

  • tolerance of 7 % sodium chloride solution,

  • indole test,

  • catalase test,

  • H28 production,

  • citrate utilization,

  • gelatin hydrolysis

  • acid from: glycerol, lactose, rhamnose and salicin,

  • Gram stain.

All tests should include a known C. sepedonicum control. Nutritional and physiological tests should be made using inocula from nutrient agar subcultures. Morphological comparisons should be made from nutrient dextrose agar cultures.

For the IF test, cell populations should be adjusted to 106 cells/ml. The IF titre should be similar to that of the known C. sepedonicum culture.

For the eggplant test cell populations should be adjusted to c 107 cells/ml. Eggplant tests should be made using 10 plants for each of the test organisms, again using known C. sepedonicum culture and sterile water controls; with pure cultures typical wilting should be obtained within 20 days but plants not showing symptons after this time should be incubated for a total of 30 days at temperatures conducive to eggplant growth but not exceeding 30oC (Appendix 5). If after 30 days symptoms are not present, the culture cannot be confirmed as being a pathogenic form of Corynebacterium sepedonicum.

Test C. sepedonicum
O/FInert or weakly oxidative
Oxidase-
Catalase+
Nitrate reduction-
Urease activity-
H2S production-
Indole production-
Citrate utilization-
Starch hydrolysis- or weak
Growth at 37o-
Growth in 7 % NaCl-
Gelatin hydrolysis-
Aesculin hydrolysis+
Acid from:
— Glycerol-
— Lactose- or weak
— Rhamnose-
— Salicin

Back to top

Options/Help

Print Options

You have chosen to open the Whole Directive

The Whole Directive you have selected contains over 200 provisions and might take some time to download. You may also experience some issues with your browser, such as an alert box that a script is taking a long time to run.

Would you like to continue?

You have chosen to open Schedules only

The Schedules you have selected contains over 200 provisions and might take some time to download. You may also experience some issues with your browser, such as an alert box that a script is taking a long time to run.

Would you like to continue?

Close

Legislation is available in different versions:

Latest Available (revised):The latest available updated version of the legislation incorporating changes made by subsequent legislation and applied by our editorial team. Changes we have not yet applied to the text, can be found in the ‘Changes to Legislation’ area.

Original (As adopted by EU): The original version of the legislation as it stood when it was first adopted in the EU. No changes have been applied to the text.

Close

Opening Options

Different options to open legislation in order to view more content on screen at once

Close

More Resources

Access essential accompanying documents and information for this legislation item from this tab. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as adopted version that was used for the EU Official Journal
  • lists of changes made by and/or affecting this legislation item
  • all formats of all associated documents
  • correction slips
  • links to related legislation and further information resources
Close

More Resources

Use this menu to access essential accompanying documents and information for this legislation item. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as adopted version that was used for the print copy
  • correction slips

Click 'View More' or select 'More Resources' tab for additional information including:

  • lists of changes made by and/or affecting this legislation item
  • confers power and blanket amendment details
  • all formats of all associated documents
  • links to related legislation and further information resources