What Do Sweet Potato Weevil Larvae Look Like?

What Do Sweet Potato Weevil Larvae Look Like?

Sweet potato weevil larvae are easy to identify. Here are their physical characteristics and habits:

Physical Characteristics

• Entirely milky white and plump, stubbier than grain weevils
• No distinct thoracic or abdominal legs. They move by wriggling
• Pale brown head with a pair of short chewing mouthparts for feeding on tuber flesh
• About 5-6 mm long, slightly larger than a grain of rice

Habits

• The larva spends its entire life cycle inside the tuber
• It never leaves the tuber from hatching to pupation
• You won't see them on the floor or in wall cracks — only by cutting open an infested sweet potato can you see the white larvae inside the tunnels

Damage Symptoms

• Tuber flesh fed on by larvae turns blackish-brown
• It gives off a bitter, foul odor caused by chemical changes in the tuber triggered by larval excrement
• The tuber flesh produces toxic substances. Blackened flesh should not be eaten
• It's best to discard the entire tuber

What Finding Them Means

If you cut open a sweet potato and find white larvae and black tunnels inside, it means the tuber was already infested with eggs before storage, or that adults have been continuously breeding and laying eggs in the storage environment.