Resistance detection of field populations of Echinochloa spp. to penoxsulam

Penoxsulam is a new acetolactate synthase inhibitor (ALS) herbicide developed by Dow AgroSciences. In order to explore the sensitivity of Echinochloa spp. to penoxsulam on rice field, whole-plant bioassay experiments were conducted to evaluate the resistance level of 70 field populations of Echinochloa spp. from main rice production in seven provinces of China. The results showed that 50.0% of the 70 populations had evolved high resistance, 47.1% of the populations was moderate resistance, and only 2.9% of the populations exhibited low resistance. None populations were sensitive to penoxsulam. More than 60% of the populations had evolved high resistance from Hubei, Anhui, Ningxia and Heilongjiang Province. The populations of high level resistance was more than 25% in other three province. More than 60% of the population with moderate level resistance were from Hunan, Jiangxi and Jiangsu Province, and the populations of 20.0%-40.0% were also with moderate level resistance in others 4 provinces. The 10.0% and 12.5% of population were with low level resistance in Hubei and Heilongjiang Province, while other 5 provinces had no low level resistant populations. This work investigated the evaluation and monitoring of the field resistance of populations of Echinochloa spp. to penoxsulam, which provided a theoretical basis for the scientific application of penoxsulam to control Echinochloa spp. in the main rice cultivation area.