How to Manage Pests

Pests in Gardens and Landscapes

Potato tuberworm—Phthorimaea operculella

Potato tuberworm larvae are dull white to pinkish and do not grow longer than 0.5 inch. They have dark heads. They are found tunneling in tubers, stems, fruit, or leaves.

Identification of species | Life cycle


In tomatoes, tuberworms burrow into fruit and into terminal stems, causing them to die. In potatoes, they tunnel into tubers, stalks, and leaves. Tuber eyes turn pink with excrement and silk.


Damage to tomatoes, eggplant, or peppers can be avoided by not planting these crops near infested potato crops or following a potato crop in a garden. In potatoes, keep plants deeply hilled with soil when planting. Don't allow soil to crack. Sprinkler irrigation will help keep soil surface sealed. Harvest potatoes promptly. Destroy infested tubers or store them at temperatures below 52° F to prevent tuberworm development.

Potato tuberworm larva
Potato tuberworm larva

Tuber damage in potatoesTuber damage in potatoes

Statewide IPM Program, Agriculture and Natural Resources, University of California
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