Submitted to: Potato Progress
Publication Type: Popular Publication
Publication Acceptance Date: February 1, 2004
Publication Date: April 1, 2004
Citation: Boydston, R.A., Seymour, M.D., Spellman, D.E. 2004. Volunteer potato forecast for the columbia basin 2004. Potato Progress. Washington State Potato Commission. 4(2):1-3. Technical Abstract: Volunteer potatoes are a serious weed problem for growers in the Columbia Basin due to mild winter temperatures in the Columbia Basin that fail to kill tubers. In winter of 2003-04, air temperatures dropped well below temperatures required to kill potatoes in early November, late December, and early January, but significant snow cover during the latter two events prevented killing temperatures to develop even in the top 2 inches of the soil profile. Based on data from buried thermocouples in the northern and southern Columbia Basin cold temperatures in early November probably caused the most damage to potato tubers, as temperatures reached below 28° F in the top 2-3 inches of soil in the northern Columbia Basin. Deeper buried potatoes were probably not harmed. In the lower Columbia Basin it appears soil temperatures at 2 in. depth never reached killing temperatures the entire 2003-04 winter season. Examination of potato fields near Prosser, WA on January 29, 2004 revealed that potato tubers left after harvest were killed only at the 1-2 inch depth of the upper soil profile and no injury to tubers has occurred at deeper soil depths. Unless additional low temperatures cause deeper freezing of the soil profile, we estimate that tuber mortality in the lower Columbia Basin will be minimal and we predict major volunteer potato populations in 2004. Recommendations for volunteer potato in rotation crops are summarized.