Injury of sugar cane roots by the white grub, Dasylepida sp. (Coleoptera: Scarabaeidae), in the Miyako Islands [Japan]

We clarified that two white grub species, Dasylepida sp. (Coleoptera: Scarabaeidae) and Anomala albopilosa sakishimana (Coleoptera: Scarabaeidae) infested the roots of sugar cane severely and caused the blighted stalks in Miyako Islands through the field survey from Nov. 1997 to Jan. 1998. This is the first record that the larvae of Dasylepida sp. injure sugar cane. Third instar larvae of Dasylepida sp. are smaller in head width and have a whiter body color than those of third instar larvae of A. albopilosa sakishimana. When these two species of larvae were exposed to the ground surface, A. albopilosa sakishimana larvae immediately burrowed into the ground but Dasylepida sp. larvae were extremely sluggish and unable to dig into the ground. The mean number of larvae of Dasylepida sp. on damaged stools was significantly greater than that of A. albopilosa sakishimana. In Miyako Island, larvae of A. albopilosa sakishimana were found extensively from the interior to the coastal areas, whereas occurrence of larvae of Dasylepida sp. was restricted to the interior areas where damaged fields are frequently found.