A correction of my earlier post on Burma:
If a March 7, 2006 Reuters report - War on opium gives Golden Triangle a different hue - is accurate, that war on opium has been largely successful.
The Burma Backstory, via Kos
The Reuters article gives a reason why the crop substitution success may not translate to Afghanistan - it's a matter of the crop yield being so high in Afghanistan. Still, there was a time when Afghanis grew other crops ...