INTEGRATED WEED MANAGEMENT IN FCV TOBACCO ( NICOTIANA TABACUM ) GROWN UNDER IRRIGATED ALFISOLS

Abstract

Tobacco yield loss due to weed competition is the most important factor that causes yield and quality reduction. Due to the scarcity of human labour, manual weeding is becoming difficult in tobacco. In situations where manual weeding and intercultural operations are not done on time due to adverse soil and weather conditions use of herbicides is the obvious choice in FCV tobacco weed management. Hence, this study was proposed by inclusion of herbicides in weed management in FCV tobacco under irrigated Alfisols. The field experiment was conducted in RBD with 10 treatments viz.1. Pre-plant soil incorporation (PPI) of Pendimethalin 3 days before planting + Quizalofop-ethyl 30 DAP 2. PPI of Pendimethalin 3 days before planting + Quizalofop-ethyl 75 days after planting(DAP) 3. Post emergence application (PEA) of Quizalofop-ethyl at 15 DAP 4. PEA of Quizalofop-ethyl at 60 DAP 5. PEA of Quizalofopethyl at 75 DAP 6. PEA of Quizalofop-ethyl at 15 + 75 DAP 7. PEA of Quizalofop-ethyl at 60 + 90 DAP 8. PEA of Quizalofop-ethyl at 75 + 125 DAP 9. Weed free check 10. Un weeded check integrated with inercultural operations and replicated thrice. Statistically lower weed dry matter production was recorded wherever herbicide application was done at 30, 60, 90 days of planting and at harvest in tobacco. Spraying of Quizalofop-ethyl at 15+75 days after planting effectively controlled the grassy weeds and also gave higher yields when compared to weed free check. Leaf reducing sugars, nicotine and chlorides were well within the desirable limits. Integrated weed management practices could not influenced the soil chemical properties significantly. Two post emergence sprays of Quizalofop-ethyl @ 60 g a.i./ha at 15 and 75 DAP can be used in integrated weed management along with intercultures to control monocot weeds which are dominant in the irrigated Alfisol