EFFECT OF SAN-582 ON SETHOXYDIM EFFICACY IN JOHNSONGRASS (SORGHUM-HALEPENSE) AND SOYBEAN (GLYCINE-MAX)

Laboratory studies were conducted to determine the effect of SAN 582 o n the absorption, translocation, and metabolism of sethoxydim in johns ongrass and soybean. (14) C-sethoxydim adsorption in johnsongrass and soybean was enhanced 4 h after application when tank mixed with SAN 58 2. Absorption in johnsongrass increased from 18% with C-14-sethoxydim applied alone to 65% when applied with SAN 582. Absorption in soybean increased from 30% with C-14-sethoxydim applied alone to 83% when appl ied with SAN 582. The addition of crop oil concentrate also enhanced f oliar absorption of C-14-sethoxydim. Eight hours after application, fo liar absorption in johnsongrass increased from 22% with C-14-sethoxydi m applied alone to 61% when C-14-sethoxydim was applied with crop oil concentrate. Foliar absorption in soybean increased from 38% with C-14 -sethoxydim applied alone to 59% when C-14-sethoxydim was applied with crop oil concentrate. When C-14-sethoxydim was applied in combination with crop oil concentrate and SAN 582, foliar absorption was 84% or m ore in both johnsongrass and soybean 4h after application and did not increase over time. Minor differences in translocation were observed, but these differences were not sufficient to account for the increase in foliar activity observed when SAN 582 is tank mixed with sethoxydim . SAN 582 did not affect metabolism of sethoxydim in either species. B ased on these data, it appears that SAN 582 increases the efficacy of sethoxydim by enhancing foliar absorption.