They are struggling because there is insufficient water to grow them due to Afghanistan's continuing drought.
Wheat requires substantially more irrigation than do poppies.
That means that the farmers in Afghanistan's most fertile provinces will be hard hit economically this year by the Taliban's order in July not to plant opium poppies. Many farmers had become economically dependent upon growing opium over the past years. They were, let's say, dissatisfied with the effects on their lives. One reason for the ban's severe economic impact is that in Afghanistan's war-torn economy, the only source for rural credit until now has been opium merchants. The merchants provided farmers with loans at the beginning of the planting season that assured them enough money for expenses until the next harvest.