(A. S. CHANNABASAVANNANAGARAJ2023-12-292023-12-292023-12-29https://krishikosh.egranth.ac.in/handle/1/5810204964A field experiment was conducted during Kharif and rabi seasons of 2019-20 at Agricultural Research Station, Malnoor to study the efficacy of dinitroaniline (ethalfluralin 36 % EC) herbicide on weed control efficiency, growth, yield and economics of Bt cotton. The experiment consists of 13 treatments which were laid out in randomized complete block design with three replications. The treatments consist of PPI or PE application of ethalfluralin 36 % EC in nano or non nano form followed by cultural methods or PoE application of pyrithiobac sodium 10 %. These were compared with PE application of pendimethalin 38.7 CS fb IC followed by cultural methods, weed free check, hand weeding and weedy check. Among these treatments, ethalfluralin 36 % EC @ 810 g a.i. ha-1 as PE fb IC at 25, 50 and 75 DAS and the application of ethalfluralin 36% @ 810 g a.i. ha-1 as PE fb pyrithiobac sodium 10 % EC @ 62.5 g a.i. ha-1 were on par with each other and recorded significantly higher seed cotton yield, net returns and benefit cost ratio over rest of the treatments. This may be attributed to the superior yield attributes (good opened bolls, boll weight and sympodial branches plant-1) and growth attributes (plant height, number of leaves, total dry matter production) recorded in these treatments. These treatments also showed higher weed control efficiency, lower total weed count and lower weed index. The differences between nano and non nano form of ethalfluralin 36 % were non significantEnglishThesis