Don the same problem came with the Golden Triangle in Thailand and Burma - the mountain farmers were growing it because it is the best paying cash crop. Unfortunately they are cutting down the trees on the mountainsides to do it and this is causing flood/drought in the lowlands.
Here is a news excerpt
Opium production drops in Golden Triangle 26/06/2003 03:16:10
Illicit drug production is dropping in Burma and Laos, but flourishing in Afghanistan.
A report by United Nations drug experts say Afghan poppy farmers are supplying a growing heroin market in Central Asia, Russia and Eastern Europe.
The opium crop leapt in 2002 due to the ousting of the Taliban in Afghanistan.
The Taliban regime had mounted an effective eradication program.
The report, is based on surveys, satellite images and field verification.
It says opium profuction in the "Golden Triangle", comprising Burma, Laos and Thailand has dropped by 40 percent.
This suggests efforts to promote alternative income sources for poor farmers are working.
ABC Asia Pacifc / Radio Australia
Here is a link to the crime commission for those who do not trust the media