Impact of Herbicides on Physiological Growth and Yield and Enhancement of Weed Control Efficiency in Hybrid Maize

Weeds are the most important biotic constraints to maize production. Yield losses in maize due to weeds depend on several factors such as weed emergence time, weed density and type of weeds. If the weeds left uncontrolled, it results in 100% yield loss. Since, labour availability to manual weeding and higher wages, it is necessary to have the strategy of chemical control of weeds in appropriate time to attain target yield and economic benefit. In this view, field experiments were conducted at Maize Research Station, Vagarai, Tamil Nadu (India) during the season kharif of the years 2015, 2016 and 2017 under irrigated ecosystem in maize hybrid (TNMH-Co 6) to develop weed management options with new herbicide molecules. The experiments were laid out in RBD and replicated thrice. The weed management options viz., pre and post emergence herbicide applications in different doses and time with conventional hand weeding. The trials were also compared with Weedy check (control) and Weed free check. The result of the experiment revealed that the weed control efficiency was higher under pre-emergence application of [email protected]./ha fb atrazine @ 750 g a.i./ha + 2, 4 D amine salt. Higher grain yield (9768 kg/ha) was registered under atrazine (1500 g a.i./ha) pre-emergence fb halosulfuron (60 g/ha) at 25 DAS as PoE at 50 DAS, which was on par with weed free check, application of pendimethalin @ 1000 ml a.i./ha as PE fb atrazine @ 750 g a.i./ha + 2, 4 Damine (75%) at 25 DAS as PoE, application of atrazine @ 250 g a.i./ha + One hand weeding at 30-35 DAS and application of tembotrione @ 120ga.i./ha as PoE at 25 DAS.