By Lovey
Tyne And Wear,
United Kingdom 
anyone know if tiny silver whiteish worm like things about 5-10mm.long in the horse manure i have spread on my allotment will be harmful to any plants / seedlings i plant if so any advice on what to use to get rid of them ? thankful for any coments, they are about the thickness of thread
14 Nov, 2012
Answers
mm thats better. perfectly normal in well rotten manure and any composting material.
14 Nov, 2012
If it is well rotted manure then these 'things' will be wee beasties that break down dead organic matter and cause no harm to growing plants.
If they are parasites from the horses intestines they will not harm your plants but, as they only live in fresh horse manure, I would be more concerned that it is the manure itself that will cause the damage. Horse manure should be allowed to sit and rot for at least a couple of years before it is applied to the allotment or it will burn the plants.
14 Nov, 2012
Already answered in your previous question on same topic...
14 Nov, 2012