This may come as a surprise to you but when the Taliban ruled Afghanistan opium crops had al but been eliminated. 1999 was the first year in decades that no Opium was grown in Afghanistan. Why? Because the Taliban regarded Opium as un-Islamic and wanted to ban it in their drive to make Afghanistan an fundamentalist Islamic state.
It was only when the “Coalition of the willing” invaded Afghanistan that opium became Afghanistans main crops again.
In the mean time you might want to watch this little video: