Insecticide Resistance and Resistance Management Monitoring the Resistance of the Beet Armyworm (Lepidoptera: Noctuidae) to Four Insecticides in Southern China from 2014 to 2018 Pan Wang,1 Fan Yang,1 Yong Wang,1 Li-Lin Zhou,1 Hai-Bo Luo,1 Shuai Zhang,2 and Sheng-Yun Si1,3