The potato tuberworm: a literature review of its biology, ecology, and control.
The potato tuberworm, Phthorimaea operculella (Zeller), is a worldwide pest of solanaceous crops especially devastating to potatoes. Adults mate and lay eggs in foliage or tubers throughout the growing season, preferring foliage over tubers. When foliage has naturally or artificially senesced and/or tubers are accessible, they deposit eggs in or near the eye buds. The larvae mine leaves, stems, and petioles causing irregular galleries, and excavate tunnels through tubers. Foliar damage to the potato crop usually does not result in significant yield losses but infested tubers may have reduced marketability and losses in storage may be up to 100% especially in non-refrigerated systems. The greatest risk of tuber damage occurs immediately before harvest while the crop is left in the field prior to digging; additional damage may occur in storage, if conditions are not maintained properly. Potatoes that are left in the field for any length of time can become infested. The pest is difficult to control and growers rely extensively on the use of insecticides and a variety of cultural practices. After harvest, the insect may continue to develop on tubers or volunteer plants remaining in the field as well as on other solanaceous plants. Incorporation of host plant resistance together with insecticides and appropriate biological and cultural practices may provide the best management options. This review addresses P. operculella bionomics, including origins, distribution, host range, life cycle and life stage behavior; seasonal dynamics; abiotic factors; cultural, biological, and chemical control methods; and host plant resistance.