For an analysis of the situation in 2004 see
Myanmar's Wa: Likely losers in the opium war http://www.atimes.com/atimes/Southeast_Asia/FA24Ae06.htmlNote that the main growers of opium are not the Burmans, but the Wa and Shan. The Burmans are the main ethnic group, but there are several others. The main opposition has been the Karens, who were Christianized and favored by the British admistrators. Myanmar is basically another post WW II British colonial disaster. Another multi-ethnic mosaic like Iraq or Afghanistan that was cobbled together in London.
From
"Opium production surges in Myanmar, UN says"http://news.oneindia.in/2007/10/10/opium-production-surges-in-myanmar-un-says-1192037575.htmlThe ''Golden Triangle'', a notoriously lawless region spanning parts of Myanmar, Thailand and Laos, has ceased to be a big supplier of opium, from which heroin is made, thanks to a concerted campaign over the past decades. ''The significant downward trend in Southeast Asia risks being undercut by an alarming upsurge in opium cultivation in Myanmar,'' said the office. Laos has cut output by 94 per cent in a decade, Thailand has had no significant production for almost 20 years, and Myanmar's share of the world market shrivelled from 63 per cent to 6 per cent between 1998 and 2006, the UNODC study said. But opium cultivation in Myanmar, formerly Burma, increased by 29 per cent to 27,700 hectares (66,480 acres) in 2007, while output rose by 46 per cent due to improved yields, it added.But note that despite the headline, the Myanmar production was still down a lot and a lot less than Afghanistan's.
UN reports more opium coming from Myanmarhttp://www.nytimes.com/2009/02/02/world/asia/02iht-drug.1.19860783.htmlThis ia a more recent article that again notes a small increase in Myanmar, but the body of the article indicates that both the Chinese and the Burmese governments are working to control opium production in the ethnic rebel areas in the hill country.
As for western involvement --
Multiple realities at the Golden Trianglehttps://www.uni-hohenheim.de/entwicklungs-soz/publications/SOAS%20Opium.pdfThis discusses the role of opium among Tai and Tibeto-Burmans in the highlands of Southeast Asia.
One excerpt is -
In the context of the cold war, opium was a crucial link between the CIA and the 8th army of the Kuomintang. The 8th army was active in southern China and could not move to Taiwan. They escaped to Burma to continue their fight against the Peoples Republic from there and found a ready ally in the CIA. Opium was the main source of revenue for the army, and the CIA contemplated to use the army for the roll back in China. Later, besides the Kuomintang, opium linked the CIA to Hmong groups in the Plain de Jarre in Laos to fight against the Northern Vietnamese and the communist Pathet Lao. While the Kuomintang established themselves as dominant power within eastern Burma and northern Thailand, the Hmong soldiers in eastern Laos never were able to gain an upper hand, and were resettled in Montana, southern France and Thailand at the end of the “Vietnam war” in the mid seventies.(McCoy 1997)More paragraphs follow. And you can google up plenty of references to the relationship between Golden Triangle opium and Cold War actors.