Early mortality syndrome of the type more accurately known as Acute Hepatopancreatic Necrosis Disease is causing major losses in marine shrimp in a number of Asian countries. The disease is associated with infection by a strain of the bacteria Vibrio parahaemolyticus. Here we describe a project to reduce the incidence of disease and improve crop outcomes for small-scale farmers in Thailand via an adaptive learning approach, implemented in association with farmer societies and collectives.