Observations on a crane fly,Tipula dorsimacula Walker, that damages potato tubers in Idaho

Summary

Damage to potato tubers in Idaho by the larvae of the crane fly,Tipula dorsimacula Walker, consists of round punctures varying in depth from shallow pits to one inch. The winter is spent in the larval stage. Adults emerge and deposit eggs during May or early June. There is a single generation annually. Observed damage has occurred in fields planted to potatoes following spring plowing of alfalfa. Early season development of the larvae is presumably on the alfalfa refuse. Then the larvae transfer to and feed on potato tubers commencing about mid-August when the organic refuse in the soil becomes low. In a few instances damage to small fields or parts of fields, has been sufficiently extensive to reduce the grade of potatoes or make them unsalable.