Submitted to: Spud Topics
Publication Type: Trade Journal
Publication Acceptance Date: January 1, 2001
Publication Date: February 1, 2001
Citation: SEYMOUR, M.D., BOYDSTON, R.A. VOLUNTEER POTATO FORECAST 2001. SPUD TOPICS. 46(12):3. 2001. Interpretive Summary: Volunteer potatoes are a serious weed problem in potato rotations. Mild winter soil temperatures result in an excessive number of surviving potato tubers resulting yield loss in rotation crop and costly control measures for potato. Researchers at the USDA-ARS at Prosser have more clearly defined the critical temperatures for tuber injury and death, and field trials monitor soil temperatures and tuber winter kill under field conditions. Therefore, researchers are able forecast the potential for volunteer potatoes early in the crop year based on field soil temperature data and on limited field sampling. Volunteer potatoes are likely to be plentiful in the lower Columbia Basing in 2001. Control measures will be necessary to minimize competition with rotational crops and formation of new daughter tubers that can carryover into subsequent crops. Fumigation prior to planting will eliminate approximately 67 percent tof surviving tubers. Herbicide, cultivation, and rotation crop options are discussed.
Technical Abstract: Results of soil temperature monitoring and sampling of potato tubers left in the field after the 2000 harvest are presented and discussed in relation to the potential volunteer potato problem expected in 2001. Temperatures this winter at Othello and Paterson have been colder than last year, but not sufficiently cold to freeze tubers beyond 4 inches in depth. Soil temperatures of 24.5 degrees F at 2 inches deep near Othello during the second week of December likely killed tubers within 2 inches of the soil surface, representing about 49% of the total number present. Temperatures of 28.1 degrees F at 4 inches deep probably killed a further 10% of total tubers present. Below 4 inches deep, tubers likely survived minimum temperatures of 31 degrees F during the same period. At Othello about 60% of tubers present in grower fields have been killed or injured. Minimum air temperatures at Paterson during the second week of December were 17 degree F during the second week of December and probably killed al tubers on the surface, and soil temperatures of 28.8 degrees F at 2 inches deep killed of injured another 10% of total tubers present. Temperatures below that depth were insufficient to kill tubers, and as a result we estimate that at Paterson only about 40% of tubers present in grower fields fields have been killed or injured to date. Recommendations for volunteer potato control in rotation crops are discussed.