Such roadside exchanges, repeated regularly during peak harvest season, long provided a ready market for smallholder avocado growers in a country that's sometimes ranked as the world's poorest. But the transactions now promise real earnings thanks in part to the intervention of the national government and farmers' cooperatives that worked to set terms for foreign avocado dealers.

Just a year ago, farmers selling their avocados to the transporters earned 10 cents per kilogram (2.2 pounds), far less than the price for a small bottle of water. These days, they get roughly 70 cents for the same quantity, a meaningful increase for people who mainly farm to feed their families.

A major change in the trade is that payments in U.S. currency now go into the bank accounts of cooperatives that pay their members directly almost as soon as the avocado haulers leave. Acting as intermediaries, groups such as Green Gold Burundi, which has its headquarters in the northern province of Kayanza and represents 200,000 farmers nationwide, say they are better positioned than individual growers to stem exploitation.