The primary visible symptoms of ambrosia beetle damage are small 1-2 mm diameter holes, usually near the base of the trunk with small sawdust plugs protruding from the trunk holes (Figs. 1 and 2). These tiny galleries extend inside in random directions for up to 30cm or so. Ambrosia beetles are often found in palms with rotting trunks, but the beetles themselves are not believed to be responsible for palm deaths.
Some species of bagworms have small perpendicular larval structures that are superficially similar to the frass plugs of ambrosia beetles. The frass plugs are rather crumbly, whereas bagworm "bags" are rather tough.
Ambrosia beetles (Xyleborus spp. and Platypus parallelus) burrow into the trunks of presumably stressed palms where they feed on the ambrosia fungi that they cultivate.
Ambrosia beetles are cosmopolitan in distribution.