Bioassay, Bispyribac-sodium + metamifop, Indicator plant, Maize, Residue

Bioassay studies were carried out to assess the residual effect of herbicide mixture, bipyribac-sodium + metamifop 14% SE in soil with indicator plant.  A screening trial with three test crops, viz. cucumber, sunflower and maize indicated that maize was the best indicator plant, because it recorded the highest regression co-efficient for the parameters tested such as fresh and dry weight of shoot, shoot length and root length. The shoot dry weight of maize was identified as the best parameter to detect the phytotoxic residue in soil. The bioassay conducted with maize as an indicator plant in the post experiment soil revealed that there was no significant difference among the treatments (bispyribac-sodium + metamifop at 60, 70, 80, 90 g/ha, bispyribac applied alone at 25 g/ha, hand weeding twice and weedy check) during both the seasons in germination percentage, shoot length, root length, fresh weight and dry weight of maize plant. Thus it can be inferred that the herbicide mixture, bispyribac-sodium + metamifop did not leave any phytotoxic residues in soil.