Bio efficacy testing of sequential application of pendimethalin followed by florpyrauxifen-benzyl in aerobic rice

Abstract

A field study was conducted on sandy clay loam soils at agricultural research station Ragolu, A.P. India during Kharif, 2016.The trial was conducted in Randomized Block Design with seven treatments Viz., T1-Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Florpyrauxifen-benzyl 2.5%EC @ 31.25 g a.i/ha at 4-7 leaf stage of weeds; T2-Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Florpyrauxifen-benzyl 2.5%EC @ 37.5 g a.i/ha at 3-4 leaf stage of weeds; T3-Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Bispyribac sodium 10 SC @20 g a.i/ha at 3-4 leaf stage of weeds; T4-Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Metsulfuronmethyl + chlorimuronehtyl – 20 %WP @ 4 g a.i/ha at 3-4 leaf stage of weeds; T5-Weed free Condition; T6-Hand weeding twice at 15 and 35 DAS and T7-Weedy Check replications four times. Results revealed that in aerobic rice, reduction in grain and straw yield due to weeds was 54.64% and 24.68 % respectively. Sequential application of Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Florpyrauxifen-benzyl 2.5%EC @ 37.5 g a.i/ha at 3-4 leaf stage of weeds was effective controlling weeds with 6.19 weed index, 92.3 % weed control efficiency resulted into at par yield to that of weed free condition. Among chemical weed management treatments, number of panicles m-2, number of filled grains per panicle,1000 grain weight, grain and straw yield of rice was the highest with application of Pendimethalin 30% @ 750 g a.i/ha on the next day of sowing followed by Florpyrauxifen-benzyl 2.5%EC @ 37.5 g a.i/ha at 3-4 leaf stage of weeds.