Abstract: Desiccants are used in potato production to remove vines before harvest to make harvest easier. We evaluated the new herbicide glufosinate-ammonium for potential as a vine desiccant, for its effect on seed tuber sprouting, and plant growth the following season. Glufosinate-ammonium was applied at 0, 0.3, 0.45, 0.6, and 0.75 kg ai/ha and compared with diquat at 0.84 kg ai/ha when applied as desiccants in mid-September in 1997 and 1998. Potato leaf and vine desiccation were rated 3, 7, and 14 d after treatment (DAT). Yields were obtained at maturity and tubers retained and stored over winter at 3 C and 95% relative humidity for determination of stem end discoloration (SED), tuber sprouting in March, and plant growth of daughter tubers planted the following year. Application of glufosinate-ammonium resulted in slower leaf and stem desiccation at 3 and 7 DAT than did diquat. By 14 DAT leaf desiccation was the same but stem desiccation was slightly less than with diquat. Tuber SED and marketable tuber yield were no different with either desiccant. At higher rates of application, glufosinate-ammonium reduced daughter tuber sprout weight but had no effect on number of sprouts in growth room sprouting tests when compared with untreated controls. Daughter tubers from glufosinate-ammonium-treated plants planted the next growing season had markedly slower emergence and established full emergence 7 to 14 d later than diquat-desiccated tubers.
Nomenclature: Diquat; glufosinate-ammonium; potato, Solanum tuberosum, #3 SOLTU.
Additional index words: Tuber sprouting test, daughter tuber replant test, Russet Burbank, Shepody, Kennebec.
Abbreviations: DAE, days after emergence; DAP, days after planting; DAT, days after treatment; RH, relative humidity; SED, stem end discoloration.