Western corn rootworm beetles likely to emerge soon Jun 4, 2012 8:00 am by jmu@illinois.eduNatural History Survey Share on Facebook Tweet Email Images INHS Insect Behaviorist Joe Spencer has observed corn rootwork larvae in their second instar, which indicates the adults can be expected to emerge in about 2 weeks. This is earlier than previous years, but not unexpected given the warm spring. Share on Facebook Tweet Email