The opium poppy isn't particularly picky. It's been successfully cultivated in North America, South America, Europe, Asia and Australasia.
It's merely dependent on the political landscape. Any failed state or civil war will prove a likely area for prodction.
Right now the Shan State is fighting a civil war with the government (dictatorship) of Myanmar,
But don't place too much trust in Afghanistan no longer being a producer. That's a government who have just realized that the economy relied on heroin production. No infrastructure so only crops with shelf-life measured in years is a practical crop for most farmers.