Weed control efficiency and selectivity of pre-emergent herbicides for garlic crop

Abstract

This study aimed to evaluate the efficiency and selectivity of pyroxasulfone and pyroxasulfone + flumioxazin at garlic cv. Ito pre-emergence. The experiment was conducted in two commercial areas in Curitibanos/SC during 2021 and 2022, using a randomized block design with four replications. The treatments consisted of the pre-emergence application of: pyroxasulfone at rates of 75, 100, and 125 g ha^-1; pyroxasulfone + flumioxazin at rates of 60 + 40, 90 + 60, and 120 + 80 g ha^-1; oxyfluorfen + flumioxazin (180 + 25 g ha^-1); pendimethalin + flumioxazin (1820 or 1600 + 25 g ha^-1); and pendimethalin alone (1820 or 1600 g ha^-1). In addition, we included an untreated and a weed-free control. This study evaluated weed density, dry mass, phytotoxicity, and bulb yields. In 2021, no weeds were reported in the cultivation area, thus only herbicide selectivity for garlic was evaluated, with all the treatments being selective without reducing the yield of garlic. In 2022, ryegrass and wild radish were predominant weeds in the crop, but the treatments caused a greater reduction in the number of ryegrass plants compared to wild radish. The plots with a higher number of wild radish plants showed a greater accumulation of dry mass due to their rapid development and large size. The most effective herbicides against these species were pyroxasulfone + flumioxazin at doses 60 + 40 and 120 + 80 g ha^-1, and oxyfluorfen + flumioxazin, while also giving a high total and commercial yield. Therefore, pyroxasulfone and pyroxasulfone + flumioxazin are selective treatments at garlic cv. Ito pre-emergence.