Using weaver ants(Oecophylla smaragdina, Hymenoptera) as biocontrol agents in fruit orchards in South Vietnam

Weaver ants (Oecophylla smaragdina, Hymenoptera) have been used for >2000 years for the suppression of insect pests in Asian mango and citrus orchards, thus constituting the oldest known example of biological control in agriculture. In Southern Vietnam, this traditional practice is rapidly disappearing as young fruit growers are intensifying their production systems, simplifying their fruit orchards and embracing pesticide-based tactics. Yet, in the Mekong Delta, pockets of smallholder farmers are still conserving weaver ant populations and relying upon these beneficial insects to keep pests at bay. Though O. smaragdina biology and ecology has been studied and (video-based) educational materials have been developed, grower uptake of these technologies is lagging. During 2019, an international collaboration program will examine (i) interactions between ants, their prey items - e.g., Tephritid fruit flies, their symbionts (as mealybugs), natural enemies, fruit trees and other non-crop plants within local orchard settings; (ii) chemical ecology mechanisms that govern those interactions; (iii) cost-effective approaches to conserve or enhance weaver ant colonies; (iv) possibilities of using O. smaragdina ants in other commercial fruit crops. Research will be coupled with farmer training and information-sharing, and thus provide a unique opportunity to rescue a time-tested, environmentally-sound and highly-effective alternative to synthetic pesticides.