Afghanistan\'s rural communities have once again increased the country\'s overall area under opium poppies, thus undermining government efforts to destroy such fields. But production has taken a blow. Afghans increased the total size of their poppy fields by 18 percent this year, a fresh survey by the Ministry of Counter-Narcotics in Kabul and the Vienna-based United Nations Office on Drugs and Crime (UNODC) showed on Tuesday. Opium poppy cultivation in the country now covers 154,000 hectares (380,542 acres), up from 131,000 hectares in 2011. But the study also revealed that despite larger areas at the disposal of local farmers, opium production fell by 36 percent to 3,700 tons due to plant diseases and long spells of bad weather. Alternatives few and far between UNOCD warned that the steep rise in cultivation came despite the Afghan government\'s latest increase in efforts to destroy poppy fields and help farmers find alternative sources of income. The report said farm-gate prices for opium remained at a relatively high level throughout 2012 at $196 (153 euro) being paid per kilogram. This kept providing a strong incentive for farmers to expand their poppy cultivation, all the more so since wheat prices had fallen sharply. In 2011, the gross income from opium was 11 times higher than that from wheat, the biggest difference since 2003. Around 90 percent of the world\'s opium comes from Afghanistan, with export earnings estimated to be worth about $2.5 billion, equivalent to 15 percent of the country\'s gross domestic product (GDP).