Abstract

Combined application of foliar herbicides with adjuvants can provide a reliable parthenium weed management option for tomato growers. A two-year field study was conducted to evaluate the effects of alkyl ether sulfate (AES) adjuvant and Achyranthes aspera plant extract (AAE) on efficacy of herbicide against parthenium weed in tomato. The treatments were post-emergence foliar spray of halosulfuron at its full (49.4 g active ingredient ha-1) and 25% reduced doses alone and in mixture with AES adjuvant and AAE. Results indicated that AES adjuvant performed better than AAE, as herbicidal treatments having AES adjuvant gave a more satisfactory weed control and higher tomato fruit yield than given by those having AAE. As compared to sole application of both the full and reduced herbicide doses, their tank-mixed applications along with AES caused significantly lower parthenium dry biomass (up to 27% and 28%) and nitrogen (up to 27% and 34%), phosphorus (up to 10% and 35%) and potash (up to 26% and 34%) uptakes resulting in significant increase in tomato plant height (up to 13% and 6%), leaves plant-1 (up to 9% and 11%), fruits plant-1 (up to 24% and 46%), single fruit weight (up to 9% and 6%), and fruit yield (up to 13% and 44%) during the years 2018 and 2019, respectively. Halosulfuron reduced dose in combination with AES adjuvant gave weed control efficacy (62% and 63%), herbicide efficacy index (1.97 and 2.19) and fruit yield (10.5 t ha-1 and 10.8 t ha-1) during the years 2018 and 2019, respectively that were statistically similar to those observed with its full dose alone. It can be concluded that halosulfuron efficacy could be enhanced and its dose could be reduced up to 25% by its tank-mixed application with AES adjuvant without compromising tomato yield and quality.