Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2000
Publication Date: February 1, 2001
Citation: BOYDSTON, R.A., ALVA, A.K. VOLUNTEER POTATO CONTROL WITH HERBICIDES AND CULTIVATION IN ONIONS. WEED SCIENCE SOCIETY OF AMERICA ABSTRACTS, 41:10 #22. 2001. Technical Abstract: Potato tubers left in the ground after harvest often fail to freeze during mild winters and subsequent plants become serious weeds in rotation crops. Studies were conducted on a Warden sandy loam soil near Prosser, WA in 1996 and 2000 to evaluate herbicide treatments combined with cultivation for control of volunteer potatoes. Whole seed potatoes were planted to simulate volunteer potatoes prior to seeding onions. Herbicide treatments included ethofumesate applied preemergence and postemergence, and bromoxynil, oxyfluorfen, bromoxynil plus oxyfluorfen, clopyralid plus bromoxynil, and fluroxypyr plus bromoxynil applied postemergence at various rates and times of application. Postemergence treatments were applied when onions were in the 2, 3, and 4-5 leaf stage. Plots were cultivated at 7 to 10 days after each postemergence herbicide application. Potato tubers were dug, counted, and weighed after onion harvest each year. Ethofumesate applied preemergence slightly injured potatoes but did not reduce potato tuber weight as much as oxyfluorfen, fluroxypyr plus bromoxynil, or clopyralid plus bromoxynil. Three applications of oxyfluorfen or oxyflurofen plus bromoxynil, two applications of either clopyralid or fluroxypyr plus bromoxynil, or three applications of ethofumesate plus bromoxynil combined with cultivation, controlled volunteer potatoes the entire season and reduced potato tuber weight and number the most. However, only sequential applications of oxyfluorfen or oxyfluorfen plus bromoxynil combined with cultivation controlled potatoes adequately without injuring onions or reducing onion yield.