IPMP3.0, Oregon State University, Copyright 2000

Mint Stem Borer



Life Cycle


Registered Insecticides


[Insect Management]


Link to large image (136K) of mint stem borer larva

Link to large image (85K) of mint stem borer adult

Mint stem borer is a pest on mint in Idaho and eastern Oregon. Adults are black, about 1/8 inch long.  Larvae are pale green to cream colored. Adults overwinter inside hollow stems or in soil debris in mint fields. Adults become active in mid-May and early June. Mated females chew a hole in a mint stem near the soil line and deposit a single egg in the wound. Larvae hatch in late June and begin feeding on the tissues in the center of the stems and usually borrow into the rhizomes. Larvae feed for 3 to 4 weeks until late July, then pupate. Generally, adults emerge about 2 weeks later. However, some larvae have been found in mint stems as late as October.  There is one generation each year.
Mint Stem Borer Larva and Adult  

This section contains information on identification of mint stem borer in peppermint.  See Baird et al. (1990) for specific information on identifcation and biology of this pest.  Mint stem borer damage is confined to production areas in Idaho and Malheur County in Eastern Oregon.