Tolerance of mung beans (Vigna radiata) to bentazone

Abstract

An experiment done in 1977 indicated that mung bean yield was reduced after spraying with bentazone. A more detailed study in 1978 with spraying times at 3, 6 and 9 weeks after sowing showed that in both Berken (green gram) and Regur (black gram) phytotoxicity was most severe when spraying was near the commencement of flowering, i.e. the 6 weeks spraying time. Visual leaf burning ratings after each spraying time indicated that Regur was more sensitive to bentazone than Berken. This was also shown by the grain yield being reduced more with Regur than Berken for bentazone applications at 3 or 9 weeks after sowing. Where two applications of bentazone were made a large reduction in yield occurred if one of the applications was at 6 weeks after sowing. Again, applications at 3 + 9 weeks affected Regur more than Berken. Bentazone influenced yield most by reducing the number of pods per plant, but there was also a significant reduction in the number of seeds per pod. Grain size was smaller with increased and repeated rates of bentazone with Regur, but larger with Berken.