Effect of New Pre-and Post-Emergence Herbicide Molecules in Maize on a Sandy Loam Soil of Telangana in India

Aim: To evaluate the efficacy of new pre and post-emergence herbicides on crop growth, yield attributes and yield in kharif maize. Study Design: Randomized Block Design. Place and Duration of Study: Agriculture Research Station, Karimnagar, during kharif, 2023. Methodology: The experiment involved ten different treatments arranged in a randomized block design, with three replications for each treatment. 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). Results: It was notable that at 30, 60, 90 days after sowing (DAS) and harvest, the weed-free treatment (HW at 20 and 40 DAS) recorded the maximum weed control efficiency, plant population, plant height, leaf area, dry matter production, cob length, cob girth, number of kernel rows cob-1, number of kernels cob-1, grain yield, stover yield and harvest index at both initial and final stages. Among the herbicidal treatments, significantly higher weed control efficiency, plant height, leaf area, dry matter production, cob length, cob girth, number of kernel rows cob-1, and number of kernels cob-1 were recorded by the application of pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb tembotrione @ 0.12 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS which was found on par with pyroxasulfone @0.1275 kg a.i ha-1 as PE fb topramezone @ 0.252 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS, mesotrione + atrazine (RM) @ 0.875 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS, topramezone + atrazine (RM) 0.775 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS and pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb halosulfuron methyl @ 0.0675 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS. However, significantly lower plant height, leaf area, dry matter production, cob length, cob girth, number of kernel rows cob-1, number of kernels cob-1, grain yield and stover yield were observed under weedy check treatment. Application of pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb tembotrione @ 0.12 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS (6875 and 7792 kg ha-1) recorded the significantly maximum grain yield and stover yield which was on par with pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb topramezone @ 0.252 kg a.i ha-1 as POE at 20 DAS fb HW at 40 DAS (6406 and 7195 kg ha-1), mesotrione + atrazine (RM) @ 0.875 kg a.i ha-1 as POE at 20 DAS fb HW at 40 DAS (6250 and 6944 kg ha-1), topramezone + atrazine (RM) 0.775 kg a.i ha-1 as POE at 20 DAS fb HW at 40 DAS (6039 and 6583 kg ha-1) and pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb halosulfuron methyl @ 0.0675 kg a.i ha-1 as POE at 20 DAS fb HW at 40 DAS (5917 and 6806 kg ha-1). Conclusion: Based on the results of this investigation in maize, it can be concluded that among various weed control tactics, application of pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb tembotrione @ 0.12 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS, pyroxasulfone @ 0.1275 kg a.i ha-1 as PE fb topramezone @ 0.252 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS and mesotrione + atrazine (RM) @ 0.875 kg a.i ha-1 as PoE at 20 DAS fb HW at 40 DAS proved to be the most effective herbicides in controlling weeds. This regimen showed superior performance in growth, yield attributes, and overall yield due to the high weed control efficiency of these herbicides.