im  not a very good green finger, this is just me having a go

 

These spring onions were growing very well,  in less than a week some sort of disease has basically wiped the whole crop out! 

 

Can anyone tell me what it is and how to combat this as it's spreading real quick in this veggie patch.  

 

Not sure weather it's the horse or sheep manure I used about a month ago.

 

 

What do the roots look like?Could be Army Worm.  They eats the roots only and you cant see them.

So they aren't the type that eats, roots, shoots and leaves?

It's raining  down where I am: Point Cook

 

i got told to chop it all down which I have but here's some ripped out of the ground. 

My apologies 

 

Try this,  pulled out of ground and then washed.

You're right about not having a green finger  

Nah, generally the roots are gone.

It looks like you have introduced something into the soil. I'd take some of the onions to your local gardening place mate.

Could well be a soil fungus that was introduced by the Manure.