ID

3104-1560

Authors as Published

Eric Day and Alexandra Spring, Department of Entomology, Virginia Tech

Figure 1 Potato tuberworm
Life stages of the Potato Tuberworm (USDA)

Description

Pinkish white, brown head, up to 1/2 inch long.

Common Host Plant(s)

Potato. Also found on eggplant, tomatoes and pepper.

Damage

Tunnels in stems, leaves, and tubers. Shoots wilt and die.

 

 

Distribution

Some southern states and California; infestations localized.

Lifecycle

Larvae or pupae overwinter in tubers or in the soil. Moths appear in spring and may be seen at dawn or dusk when they are normally active or when plants are disturbed. Females lay 60-200 eggs, singly, on plants in as little as four days. Usually eggs are deposited in the tuber eyes or on the underside of potato foliage. Larvae emerge in 3-6 days. Larvae often enter potato tubers through the eyes, leaving frass around the eye. Larvae may feed near the tuber surface or tunnel deeply into the tuber, leaving a trail of excrement along their path. During the summer larvae mature in 7-10 days and pupate in soil or plant debris around potato plants. Second generation moths emerge in approximately a week. Multiple generations occur annually in Virginia.

Cultural Control

Protective measures for controlling the potato tuberworm include the following: 
1) plant only seed pieces that are not infested, 
2) cultivate so as to hill the soil against the plants - keeping at least 2 inches of soil over the developing tubers, 
3) harvest as soon as the crop is mature. During harvest, do not leave the dug potatoes in the field overnight, and do not cover piles of potatoes with potato tops, 
4) destroy all culled or infected potatoes as soon as possible, 
5) store tubers at temperatures below 52 degrees F is possible and practical. Use either new or thoroughly cleaned bags or baskets when storing. The storage area should be screened or enclosed in such a way that moth cannot get in. Without such an enclosed storage area, moths can still fly in and still become a problem even though the storage area was clean and potatoes insect-free when stored.

Organic/Biological Control

Natural enemies of the potato tuberworm include two braconid wasps (Orgilus lepidus Muesebeck and Bracon gelechiae Ashmead), which parasitize the larvae.

Chemical Control

There is no known chemical control for this insect in stored potatoes.


Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.

Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.

Publication Date

April 25, 2011

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