Tuber Flea Beetles

Are your potatoes going bald?
 
Bare patches on potatoes may indicate tuber flea beetles.

Tuber flea beetle damage (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0

Tuber flea beetles are native to North America, but you will probably never see one. These dull reddish-black insects are only 7/100 of an inch long (2mm), but the damage they cause is much larger. And their range is expanding into South and Central America. Other plants vulnerable to tuber flea beetle feeding include eggplant, groundcherries, and tomatoes.
 
Tuber flea beetles (Epitrix tuberis) are ranked as the Number One potato pest among their cousins:

• E. similaris (no common name)
• potato flea beetle (E. cucumeris)
• tobacco flea beetle (E. hirtipennis)
• western potato flea beetle) E. subcrinita)

 
Tuber flea beetles and their cousins are difficult to tell apart, so we will lump them together for the sake of discussion. Collectively, they are members of a group known as leaf beetles (Chrysomelidae).

Epitrix, leaf beetle (xpda) CC BY-SA 4.0

Like other flea beetles, tuber flea beetles damage fruit, leaves, roots, and tubers. Adults crawl, fly, and jump from plant to plant to eat the leaves and burrow into the soil to lay eggs. Larvae feed on roots and tubers before pupating into adults. Adult feeding causes tiny holes in leaves, creating a shothole appearance, bare patches on tubers, and leathery areas on fruit.

Tuber flea beetle larvae feeding damage to potato skin (Whitney Cranshaw, CSU/Bugwood.org CC BY 3.0 US

A three-year crop rotation goes a long way toward managing tuber flea beetles, but buying certified disease- and pest-free seed potatoes is critical. Also, it helps to keep weeds in the nightshade family away from your potato plants. You can also reduce tuber flea beetle damage by intercropping dill, marigolds, and spring onions with vulnerable crops.
 
I hope your potatoes never get fleas!