Effectiveness of Herbicides on Major Aquatic Weed Species of Dalpatsagar Reservoir, Jagdalpur

Abstract

Dalpatsagar reservoir is the biggest and oldest water bodies in Jagdalpur city of Chhattisgarh state. The water body was severely infested with different species of aquatic weeds throughout the year since last decade and it modified the structure of habitat and influenced the aquatic ecosystem. The physico-chemical properties of Dalpatsagar reservoir was also changed with season year after year that influenced the water quality and species richness in aquatic ecosystem. In order to reduce the economic, environmental, and social impacts of aquatic weed plants, different management measures was used but most of the cases use of chemical herbicide is necessary to suppress the aggressive nuisance of vegetation. Present study aims to evaluate the effectiveness of Glyphosate, 2,4-D, and Paraquat to control the different species of aquatic macrophytes. An experiment was installed at Dalpatsagar reservoir Jagdalpur, in 31 st December 2019 and effectiveness of control was evaluated at 5,10,15,20,25 and 30 days after spray. The experiment was conducted in Randomized Complete Block Design (RCBD) with three replications comprising seven treatments viz. Glyphosate (41 SL), Paraquat (24 SL) and 2,4-D (amine salt 58% SL) at 2.00 and 1.00 litre/ha with each herbicides including Absolute control. The herbicides were mixed with sticker (Latron AG-98) and sprayed in three replications by power spray machine (1HP HTP MAK ASPEE) mounted on the boat. At higher dose of Glyhosate @ 2.00 litre/ha had lesser day to yellowing, necrosis and dying than other dose of herbicide treatments, similarly 2,4-D @ 2.00 litre/ha showed the minimum day to appearing phyto-toxicity symptom in all weed species. The reduction of weed density (Plant/m 2 ) and weed dry weight (g/ m 2 ) at 20 DAS was maximum with Glyphosate @ 2.00 litre/ha followed by 2,4-D @ 2.00 litre/ha. Weed control efficiency was significantly higher in Pistia stratiotes (81.27%) and Nelumba nucifera (81.