Outbreak of erythrina gall wasp (Hymenoptera: Eulophidae) on Erythrina spp. (Fabaceae) in Taiwan

The erythrina gall wasp was first recorded damaging coral trees, Erythrina spp. (Fabaceae), in southern Taiwan in 2003; since then it has rapidly spread over the island on various species of Erythrina. Galls are formed on the leaves, petioles, young shoots, and stems. Obvious swellings could be seen in infected tissue parts, and severe infestations caused curling of young shoots, defoliation, and death of the tree. At present, six species of coral trees were recorded as suitable. The gall inducer is Quadrastichus erythrinae Kim (Eulophidae), newly reported in Singapore, Mauritius, and Réunion, which also caused severe damage in those areas. In this research, we report the symptoms, the distribution map of infested coral trees in Taiwan, identification characters of the galler, and pest control suggestions.