[Rob the rake]

Having been out of the loop for several years after a lengthy and disabling bout of sciatica it seems some things have passed me by, the dangers of aminopyralid being the most disturbing.
 
From reading blog posts on this forum it would seem that contaminated manures are the major culprits, but I've experienced similar symptoms to those described from using commercial composts, both cheap and not so cheap. Part of last year's potato crop, grown in soil augmented with "5 bags for a tenner" compost, fared very poorly. I'd put this down to the seed (saved for 15 straight years) finally breaking down with disease, but now I'm not so sure.

In a recent post it was implied that there's a test for aminopyralid. Is this so?

[Blewit]

Apart from laboratory testing some gardeners sow a couple of beans in a pot of suspect compost/manure to see if they develop symptoms of contamination. Unfortunately it's unlikely every bit of compost in a bag will be affected so you could get a clean result only to find later small pieces contain herbicide.