Submitted to: Weed Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/1/2002
Publication Date: 8/1/2002
Citation: BOYDSTON, R.A., SEYMOUR, M.D. VOLUNTEER POTATO (SOLANUM TUBEROSUM) CONTROL WITH HERBICIDES AND CULTIVATION IN ONION (ALLIUM CEPA). WEED TECHNOLOGY, 16:620-626. 2002. Interpretive Summary: Numerous potato tubers are left in the field following a commercial potato harvest. These tubers can survive and sprout in rotation crops and are difficult to control. Volunteer potatoes harbor harmful diseases, nematodes, and insects that harm potato crops, diminishing the positive effects of crop rotation. Volunteer potato control in onions requires numerous cultivations, herbicide applications, and hand weeding during the season to prevent onion yield loss and potatoes from forming new tubers. Herbicide treatments combined with cultivation were evaluated for volunteer potato control and their effect on onion yield. Most treatments tested were not effective in controlling volunteer potatoes or injured onions excessively. One effective treatment identified was three applications of oxyfluorfen followed by cultivation, which reduced the number of potato tubers 62 to 68% and tuber weight about 90% and maintained onion yields equal to hand-weeded checks. Another promissing treatment was ethofumesate applied at 0.6 kg/ha followed by ethofumesate applied postemergence and cultivation. Controlling volunteer potatoes requires an integrated approach that includes timely application of herbicides and cultivation.
Technical Abstract: Volunteer potatoes are difficult to control in onions and can greatly reduce onion growth and yield. Herbicides and cultivation were evaluated for control of simulated volunteer potatoes in onions in 1996 and 2000. Three inter-row cultivations did not control potatoes in the onion row and remaining plants reduced onion yield 73 and 50%, compared to hand-weeded checks in 1996 and 2000, respectively. Three applications of oxyfluorfen (0.2 + 0.17 + 0.17 kg ai/ha) or bromoxynil plus oxyfluorfen at 0.2 + 0.17 kg ai/ha, respectively, at the 2-, 3-, and 4 to 5-leaf stage of onions followed by a cultivation after each application reduced potato tuber weight 69 to 96% and tuber number 32 to 86% compared to cultivation alone and prevented onion yield loss associated with potatoes in both 1996 and 2000. Ethofumesate applied PRE at 0.6 kg/ha followed by POST ethofumesate plus bromoxynil and cultivation reduced potato tuber weight 90% and tuber number 68% compared to cultivation alone and onions yielded equal to hand-weeded checks. Two applications of fluroxypyr (0.3 kg ai/ha) plus bromoxynil (0.2 kg ai/ha) at the 2- and 3-leaf stage of onions followed by a cultivation after each application reduced potato tuber weight by greater than 90% in both 1996 and 2000, but onion yields were reduced 38 to 66%.