Potato Stalk Borer – Trichobaris trinotata

Potato Stalk Borer (Trichobaris trinotata)

Latin Name: Trichobaris trinotata

Common Name: Potato Stalk Borer


  • The adult weevil is a small species, measuring about 4.4 mm (0.17 in) in length and 1.7 mm in breadth (0.07 in).
  • At the base, the rostrum, or beak, bends steeply downwards.
  • The insect is small and discreet; it is black but seems grey because most of its surface is coated in small grey scales; scales are absent from the head and three patches at the base of the elytra, one in front and one on either side, which appear dark.

Host plants: Horse-nettle and eggplant are common weed hosts.

Territory: It is found in North America

Damage caused by Potato Stalk Borer: 

The larvae burrow through the stem from the hatching place on the leaf’s petiole, causing the most harm. The larvae develop in size as it penetrates, inflicting additional harm and even digging into the roots. Before producing eggs, the adults eat in the spring, leaving uneven holes in the leaves. Adults produce the least amount of harm.

Life history and Habits:

Adults emerge from reproductive diapauses in the spring, and females produce eggs in the summer. These are placed singly in holes formed by the insect’s rostrum in stems and leaf stalks or the axils of terminal leaves. The whitish, legless larvae munch their way through the stem tissues, building tunnels up to 30 cm (12 in) in length when the eggs hatch in approximately a week. The larvae pupate in the stem after passing through five or six instars over up to 106 days, with the adults emerging around twelve days later. Each year, there is just one generation.