EFFECT OF NEW PRE AND POST EMERGENCE HERBICIDE MOLECULES IN KHARIF MAIZE

The field experiment was conducted at Agriculture Research Station (ARS), Karimnagar, during kharif, 2023.This experiment was plotted in a randomized block design, with ten treatments with three replications.Treatments were T1 -Atrazine 50% WP 0.5 kg a.i ha - 1 as PE fb HW at 40 DAS, T2 -Pyroxasulfone 85% w/w WG 0.1275 kg a.i ha -1 as PE fb HW at 40 DAS, T3 -Halosulfuron methyl 5% + atrazine 48% WG (RM) 0.05625 + 0.540 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T4 -Topramezone 10 g l -1 + atrazine 300 g l - 1 SC (RM) 0.775 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T5 -Mesotrione 2.27% w/w + atrazine 22.7% w/w SC (RM) 0.875 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T6 -Pyroxasulfone 85% w/w WG 0.1275 kg a.i ha -1 as PE fb halosulfuron methyl 75% WG 0.0675 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T7 -Pyroxasulfone 85% w/w WG 0.1275 kg a.i ha -1 as PE fb tembotrione 34.4% SC 0.12 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T8 -Pyroxasulfone 85% w/w WG 0.1275 kg a.i ha -1 as PE fb topramezone 336 g l -1 w/v SC 0.252 kg a.i ha -1 as POE at 20 DAS fb HW at 40 DAS, T9 -Weedy check, T10 -Weed free (HW at 20 and 40 DAS).The experimental field soil was Sandy loam soils with a pH of 7.6 and EC of 0.23 dS m -1 .The experimental soil contains 0.28% organic carbon.The available nitrogen was low with 180 kg N ha -1 and the available phosphorus and potassium were high with 53 kg P2O5 ha -1 and 315 kg K2O ha -1 , respectively.It was observed that various weed management practices significantly influenced the grain yield, stover yield and economic returns in maize.The weed-free treatment (hand weeding at 20 and 40 DAS) led to notably higher grain (7083 kg ha -1 ) and stover yields (8042 kg ha -1 ) over other treatments.Among herbicides, the application of pyroxasulfone at 0.1275 kg a.i ha -1 as a pre-emergence (PE) treatment fb tembotrione at 0.12 kg a.i ha -1 as a post-emergence (PoE) treatment at 20 DAS fb hand weeding at 40 DAS, resulted in the highest grain yield (6875 kg ha -1 ) and stover yield (7792 kg ha -1 ).This was statistically on par with the treatment of pyroxasulfone at 0.1275 kg a.i ha -1 as PE, followed by topramezone at 0.252 kg a.i ha -1 as PoE at 20 DAS fb hand weeding at 40 DAS (6406 and 7195 kg ha -1 for grain and stover, respectively), as well as the mesotrione + atrazine (RM) combination at 0.875 kg a.i ha -1 as PoE at 20 DAS fb hand weeding at 40 DAS (6250 and 6944 kg ha -1 ).The higher benefit cost ratio was recorded in weed free treatment (2.49) and with the application of pyroxasulfone at 0.1275 kg a.i ha -1 as a pre-emergence (PE) fb tembotrione at 0.12 kg a.i ha -1 as a post-emergence (PoE) at 20 DAS fb hand weeding at 40 DAS (2.48).This was followed closely by pyroxasulfone at 0.1275 kg a.i ha -1 as PE, followed by topramezone at 0.252 kg a.i ha -1 as PoE at 20 DAS fb hand weeding at 40 DAS (2.28), as well as mesotrione + atrazine (RM) at 0.875 kg a.i ha as PoE at 20 DAS with hand weeding at 40 DAS (2.27).