Field studies were conducted from 2000 to 2003 to determine the effectiveness of potato desiccants for late-season hairy nightshade control and also their effect on hairy nightshade seed germination. Commercial sulfuric acid at 280 L/ha controlled 94 to 99% of the hairy nightshade 1 wk after treatment (WAT) in all years. Diquat at 560 g/ha and glufosinate-ammonium at 420 g/ha provided at least 93% control 1 WAT in all years except 2003 when control did not exceed 72%. By 3 WAT, hairy nightshade control ranged from 93 to 100% for all treatments, including carfentrazone-ethyl at 56 g/ha, diquat at 420 g/ha, paraquat at 530 g/ha, and sulfuric acid (proprietary process) at 280 L/ha. Treatment of plants with desiccants did not affect germination of hairy nightshade seed, with the exception of a 7% reduction in germination by the higher rate of diquat in 2001 and 2002.
Nomenclature: Carfentrazone-ethyl; diquat; glufosinate-ammonium; paraquat; sulfuric acid; Solanum sarrachoides Sendter #3 SOLSA; potato, Solanum tuberosum L.
Additional index words: Desiccation; potato vine-kill; weed seed germination.
Abbreviations: AMS, ammonium sulfate; MSO, methylated seed oil; NIS, nonionic surfactant; WAH, weeks after harvest.