The corn earworm, Heliothis zea (Boddie), is seldom a pest of economic importance in tomatoes in southern Ontario. However, in 1953 the harvest of tomatoes for processing was prematurely terminated because of the presence of this pest in the ripe fruits. In that year almost all the fields in Kent and Essex counties, involving approximately 12,000 acres, were infested, the infestations being as high as 11 per cent in individual fields. The situation was aggravated because excellent-appearing fruits with no visible larval entry holes often contained earworms. This condition occurred when the newly hatched larvae had burrowed immediately into the fruits and there completed their larval development. The entry holes soon healed, leaving small scars that were almost impossible to detect, particularly on a busy production line.