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Slimy Fungus on gravel



  • WELL .... we have had 4 bright sunny days since we sprayed the stuff  so I checked this morning - and there is none!  Daren't breathe yet as rain is forecast imminently.  We are armed with a large amount of washing soda to spray again in one week so will wait and see.  But for now, Margaret, you are a shining star!!!!

  • I'm in Delvin - county Westmeath.  Noticed the infestation about three/four years back on gravelled areas of yard.  Assumed it was a slime mould - now I know!  Worst affected areas are the lower, dampest areas.

    [I'd wondered about RU as a herbicide on the gravelled areas - which is where the infection originated.  Will have to get a replacement. I'll try Nat Ag Distributors for alternative herbicides]

    Concentrated sulphuric acid wipes it out - but that's a bit dramatic. I shall experiment with dilute solutions and see what happens.

    I am currently trying sodium hydroxide (caustic soda dry powder) on the worst affected areas.  No firm results yet (only 7 days). 

    What I need to do is to set up some glass containers, add some damp sand to each, then innoculate the surface with some Nostoc.  I'll then have to experiment with a selection of acid and alkali treatments to see what effect each will have. 

    Sodium bi-carbonate is a MILD alkali and when dissolved in water produces a pH of  8 - 9*

    Sodium carbonate is a STRONG alkali and when dissolved in water produces a pH of 13.  Hazardous; toxic; corrosive.

    Bleach is solution of sodium hypochlorite - NaOCl - used in various formulations as a cleansing, disinfecting (mild oxidizing agent).  Hazardous; toxic; corrosive.

    Ehanoic (acetic) acid is a strong organic acid and rapidly penetrates and destroys living tissue.  Hazardous; toxic; corrosive and flammable.  Vapour is a strong irritant.

    Sodium hydroxide is a strong alkali and reacts like acetic acid.  Hazardous; toxic; corrosive.

    Ammonia solutions (NH4OH - ammonium hydroxide) are often suggested for cleaning.  Strong alkali.  Hazardous; toxic; corrosive. Vapour is a strong irritant.

    * Note; pH is an inverse logarithmic scale to measure the amount of hydrogen ion (acid) present in a solution. : 0 (zero) is very strong acid; 7 is Neutral; 14 is very strong alkali (absence of acid).  Purified water should have a pH value of 6.8 or so.

  • Update on Nostoc commune

    This is quite a resistant organism.  It is tolerant of freezing + thawing and is heat resistant when dessicated (dry).  It can remain in a dormant state for months.  In its hydrated form it is likely to be least resistant to chemical attack.  The exterior surface of the organism consists of a protective layer of polysaccharide (polymerized monosaccharide sugar-like molecules).  Disruption or destruction of this layer will cause the organism to die-off.

    Polysaccharides are attacked by inorganic acids (sulphuric; hydrochloric) which disrupt the chemical bonds that link the individual sugars together in the long chain.  However, some polysaccharides may be tolerant of alkaline solutions. Wood is a complex polymer of glucose, so anything that can 'dissolve' wood is likely to also damage Nostoc.  Experimentation is advised.  Repeat treatment of affected areas appears to be essential to keep the organism away.

    Damp conditions appear best suited to the growth (or regeneration) of the organism and it has been suggested that organic phosphate run-off from agricultural fertilizer may be a factor - so the correlation between spraying with RoundUP [(N-(phosphonomethyl)glycine] - and the appearance of Nostoc, may be suggestive that RU is acting as a proxy growth promoter.  Monsanto describes RU as being 'degraded' by soil micro-organisms - but degraded to what?  They do not say.  However, if its into soluble forms of phosphate and nitrogen - that would be like blood to a vampire!

    For detailed info: type nostoc into your search engine.

  • Thank for this information, anything new that is working please let us all know

  • Hi everyone,we were plagued with this. 

    Local pest control guy said to use washing powder on it and leave it on it.

    gone and hasn't returned and it has rained loads.

    fingers crossed 

  • thank you for the info. Do you dissolve the washing powder? Appreciate your answer.

  • I first noticed this green slime some time last year and as seen in previous posts (yes - I read them all) it appears to ‘die’ during dry spells. Well we’ve had a fair bit of rain again allowing the stuff to flourish. Having read all posts it seems that Margaret Ibbs is the hero. The weather forecasters are predicting a dry day tomorrow so I’ll be out with the watering can and washing soda  - a simpler, safer and cheaper option than some of the others I’ve read. 


  • By the way - Margaret Ibbs’ original post appears on page4 of this forum, March 2016

  • We have this foul stuff in Tasmania, too. The worst of it began in an area of the turning circle which is covered in road surfacing (though not asphalt). It’s in the shade of tall trees inside the turning circle. All characteristics are as described above in this thread. It’s on a slope, though, and has spread downhill to an area in front of the shed, where there is room to park and where I clean down the deck and blades of the ride-on mower. 

    I tested boiling water on a patch, and that works like a charm. However, it would be both tedious and expensive to boil enough water to treat it all.

    Thanks for all the info. I’m going to give the Margaret Ibbs method a go!

  • thank you for this idea, will give it a try

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