Ant damage to banana fruits in Hawaii

Scot C. Nelson snelson@hawaii.edu (Associate Specialist, Plant Pathology, University of Hawaii at Manoa, College of Tropical Agriculture and Human Resourced)

Some ant species associated with banana bunches in Hawaii can cause significant damage to young fruits, especially when colonies of the ants on bunches are disturbed or agitated by bunch spraying or by bumping into plants and causing vibration disturbance to the ants. The disturbed ants eject formic acid from their abdomens as a defense reaction. The formic acid, with a pH of 2-3, burns the tender skins of the young fingers, leaving irregularly shaped, blackened areas on the fruits that expand as the fruits expand. In East Hawaii, the ant most commonly associated with this damage is the long-legged ant, Anoplolepsis longipes.