August 2010. A caterpillar in northern Laos on Boehmeria spp., is killing the trees/shrubs. Can it be identified and what is the best control?

The caterpillars match the immature stages of the sub-family Acraeinae (Lepidoptera: Nymphalidae). The species displayed is probably the Yellow coster (Acraea issoria) a slow-flying butterfly which is known to have spread into new areas within Asia. The entire genus is predominantly African.