Agriculture & Food, Volume 10, 2022

Abstract: The influence of a non-ionic surfactant and Renol on the performance and rainfastness of rimsulfuron was evaluated on two noxious broad-leaved weeds: redroot pigweed (Amarantus retroflexus) and lambsquarter (Chenopodium album). In first experiment, seven doses of rimsulfuron alone or in mixture with two adjuvants were applied to each weed species and subsequently subjected to 5mm of rain at 1, 2 and 4h after treatment (HAT) by using a rain simulator. In second experiment, the plants were sprayed with similar dosages and rain treatments of first semifield experiment, but with application of three non-iconic surfactant levels (0.04, 0.2 and 1L/ha). The results showed that the adjuvants did not improve the efficacy of rimsulfuron on Amaranthus retroflexus whereas it was completely efficient for Chenopodium album but the adjuvants enhanced both, the performance and the rainfastness, of rimsulfuron. Non-ionic surfactant was more efficient to improve herbicidal activity and rainfastness on both weed species. Increasing non-ionic surfactant concentration increased rimsulfuron activity around 10-fold for Amaranthus retroflexus compared to around 3-fold for Chenopodium album. Also reduced the rainfastness of rimsulfuron on Amaranthus retroflexus while improved the rainfastness of rimsulfuron on Chenopodium album.