Perhaps they need to try spraying the crops with RoundUp

State Department:

...

Afghanistan is the world’s leading producer of illicit opiates, accounting for nearly 90 percent of the global supply according to U.S. Government figures. Almost 8.7 percent of the Afghan population was involved in opium cultivation in 2005. Additionally, the export value of Afghan opiates in 2005 is estimated at $2.7 billion. However, 80 percent of this money goes to drug trafficking networks and does not support the local rural Afghan communities.

The cultivation, production, and trafficking of opiates is a destabilizing influence in any country, but such trafficking is particularly dangerous to an emerging democracy such as Afghanistan. Promotion of economic development, rule of law, democratic elections, and a functioning civil society must be coupled with vigorous efforts to stem the tide of illicit narcotics and combat the accompanying corruption and instability. The continued support of counternarcotics efforts must remain an important part of overall U.S. policy in Afghanistan.

According to U.S. Government figures, there was a 48 percent decrease in poppy cultivation in 2005, down from record figures in 2004. However, due to favorable climate conditions, yield per hectare was up--resulting in only a 10 percent decrease in opium production. While we welcomed this decrease in 2005, early indications show that planting has significantly increased in 2006. According to the United Nations Office on Drugs and Crime’s (UNODC’s) Rapid Assessment Survey released in February 2006, poppy planting for the current growing season increased in 13 provinces, remained stable in 15, and decreased in only three.

...

RoundUp works pretty good for me. It even took care of the Fig Ivy my wife planted too close to the house. There must be some reason they have not tried it, but what ever it is, it is not obvious to me.