Vol. 10, Issue 1 (2021)

Author(s):
Y Lavanya, K Srinivasan, CR Chinnamuthu, P Murali Arthanari, S Shanmugasundaram and CN Chandrasekhar

Abstract:
Field trials were conducted at Agricultural College and Research Institute, TNAU, Coimbatore, Tamilnadu, India, during two consecutive kharif (rainy) seasons of 2018 and 2019. The experiment was laid in a randomized block design different weed control methods viz., pre emergence (PE) atrazine at 0.5 kg a.i. ha^-1 fb hand weeding (HW) at 20 DAS, PE atrazine at 0.5 kg a.i. ha^-1 fb power weeder (PW) at 20 DAS, PE atrazine at 0.5 kg a.i. ha^-1 + pendimethalin at 1 kg a.i. ha^-1 (Tank mix), PE atrazine at 0.5 kg a.i. ha^-1 + pendimethalin at 1 kg a.i. ha^-1 fb HW at 20 DAS, early post emergence (EPOE) topramezone at 25.2 g a.i. ha^-1, PE atrazine at 0.5 kg a.i. ha^-1 fb EPOE topramezone at 25.2 g a.i. ha^-1, EPOE tembotrione at 122 g a.i. ha^-1, PE atrazine 0.5 kg a.i. ha^-1 fb EPOE tembotrione 122 g a.i. ha^-1, hand weeding twice at 20 and 40 DAS and control (weedy check) with 3 replications for each treatment. The results revealed that the experimental field was infested with all categories of weeds including grasses, broad-leaved weeds and sedges. Among them the most predominant weeds were Cynodon dactylon, Dactyloctenium aegyptium, Echinochloa colona, Amaranthus viridis, Digera arvensis and Trianthema portulacastrum. Among the chemical weed control methods PE atrazine at 0.5 kg a.i. ha^-1 fb EPOE topramezone at 25.2 g a.i. ha^-1 and PE atrazine 0.5 kg a.i. ha^-1 fb EPOE tembotrione 122 g a.i. ha^-1 recorded significantly lower weed density as well as weed dry weight of BLW, grasses, sedges and total weed at 90 DAS during 2018 and 2019, respectively. As a consequence of effective weed control, the above treatments recorded significantly higher weed control efficiency (WCE) and lower weed index (WI) during 2018 and 2019, at 90 DAS. These treatments were statistically comparable with hand weeding twice at 20 and 45 DAS. Uncontrolled weed growth in control (weedy check) recorded higher weed density and weed dry matter in maize crop during both the years of experimentation.