Opium-poppy eradication has been hailed as a success in much of Afghanistan’s north and east by the Karzi government and U.S. sources, allowing counternarcotics officials to declare 18 provinces there as “poppy-free” despite record opium cultivation in the south and southwest. Great news right…not… UN officials say that many former opium farmers in those poppy-free areas have switched to another lucrative and illegal drug crop: marijuana.

Afghanistan is now the world’s largest producer of two illegal drugs — heroin from opium poppies and cannabis.

The latest assessment on the Afghan narcotics trade says cultivation of opium poppies in Afghanistan is likely to fall this year compared to the record crops of previous years.

It says the 18 provinces labeled “opium-free” in 2008 will probably remain so in 2009. It also says seven other Afghan provinces are likely to reduce opium-poppy cultivation this year — including the biggest opium-producing province, Helmand, in the volatile south.

That means opium cultivation in Afghanistan is now overwhelmingly concentrated within the seven most unstable provinces in the south and southwest.

But officials in neighboring countries say the size and frequency of drug seizures from smugglers near the Afghan border continues to increase — highlighting the fact that many Afghan farmers who have stopped growing opium poppies are now growing marijuana crops instead.