After hatching larvae measure 1.2-1.4 mm in length, and are translucent white in colour with a dark brown head and prothoracic plate. Final instars reach 12-15 mm and are purple dorsally and green ventrally with a dark brown head and prothoracic plate.
Ovoid, ca. 0.5 x 0.4 mm in size. Pearly white when newly laid, becoming yellow and finally brown with age. Laid singly or in small groups on the ground or directly onto tubers
Damage is done to plants outside and potatoes in storage. Larvae bore into potato tubers to feed within galleries. Galleries become filled with frass and exuviae. The tubers shown no sign of infestation until the larvae bores out of the tuber to pupate. Exit holes are circular, 23 mm in diameter.
