Mint-Mint stem borer

Pseudobaris nigrina

Pest description and crop damage A small white grub, 0.08 to 0.16 inch long, with a brown head and no legs. Damage is to the main root, causing injury or death to the central stalk, which usually breaks off. It is found in eastern Oregon and Idaho. . It can infest mint rootstock for export.

Management-chemical control

No insecticides are registered. However, aphid or looper sprays applied in mid- to late May generally reduce stem borer populations.