The VietGap-met longan was grown in nearly 20 hectares in Ham Tu commune in Khoai Chau district and Hong Nam commune in Hung Yen city, of northern Hung Yen province.
Hong Nam commune grows longan trees on over 170 hectares, producing an annual average of 2,000 tonnes of fruit.
Hung Yen has 3,000 hectares of longan trees, yielding 35,000-40,000 tonnes per year, mostly in Khoai Chau, Hung Yen city, and Kim Dong district.
As many as 175 households, owning 20 hectares of longan trees have been granted the codes to export their products to the US.
They are required to strictly follow Vietnamese Good Agriculture Practice (VietGap) standards like using only permitted bio-pesticides.
The US Department of Agriculture approved the import of fresh lychee and longan from Vietnam in 2013.
The fruits will be subject to a system that includes treatment and inspection requirements and restrictions on distribution.
As a pre-condition for entry, the fruits must be grown in orchards registered with and monitored by the National Plant Protection Organisation of Vietnam to ensure they are disease-free.
Vietnam hopes to export 600 tonnes of lychee and 1,200 tonnes of longan to the US every year.