Soil residual activity and plantback periods for the herbicides saflufenacil and topramezone

Abstract

To quantify soil residual activity and plantback periods for two maize herbicides saflufenacil and topramezone different rates were applied to a cultivated soil and samples (05 cm) collected at regular intervals for glasshouse bioassays Phytotoxic residues of saflufenacil applied at 17 g ai/ha the rate used for conservation tillage and pasture renovation persisted in the soil for lt; 2 weeks for the susceptible species viz white clover onion carrot and radish Residual activity from 102 g ai/ha the rate recommended for maize dissipated within 4 weeks for all species Wheat ryegrass carrot squash onions and tomato were not affected by topramezone residues from rates up to 202 g ai/ha in soil collected 2 weeks after treatment (WAT) However peas white clover and radish all suffered damage in samples collected 2 WAT By 4 WAT only white clover and peas exhibited minor phytotoxicity