Since first reported in damaging numbers in Oregon in 2002, the potato tuberworm (PTW) Phthorimaea operculella, spread across the Columbia Basin, the major potato production region of Oregon and Washington, currently threatening about 160,000 acres of potatoes valued at more than $500 million. In 2005 trials, cultural and chemical control methods proved to be effective at reducing PTW populations. The objectives of these studies were (1) to determine the minimum pre-harvest interval between initial application of insecticides and vine kill for effective control; (2) to study the effects of green foliage and increased moisture on PTW damage; (3) to determine the effectiveness of rolling or covering hills to remove tuber access via soil cracks. In general cultural practices appear to reduce PTW tuber damage. Little to no damage occurred in tubers until the percent green foliage decreased to 10%. Pre-harvest application of insecticides (Esfenvalerate, methamidophos, and methomyl) prior to vine kill significantly reduced tuber damage as compared to the control, but there was no apparent advantage to beginning control efforts earlier in the season than later. Daily irrigation following vine kill reduced tuber damage, and chemical vine kill reduce tuber damage as compared to natural senescence. Rolling of potato hills in sandy soils may expose tubers and is not recommended in this Columbia Basin area. Covering hills with soil provides good protection but must be done at vine-kill.