Differential sensitivity of field muskmelon (Cucumis melo L. var. agrestis Naud.) populations to nicosulfuron, imazapic, fomesafen and bentazon

Cucumis melo L. var. agrestis Naud. (field muskmelon), a troublesome weed affecting corn, soybean and peanut fields, is difficult to control and drastically reduces crop yields. Farmers have reported that nicosulfuron, imazapic, fomesafen, and bentazon, which are common herbicides used in corn, soybean and peanut fields, do not control field muskmelon effectively. This lack of control might be due to the evolution of resistance to these herbicides in field muskmelon. Thus, this study was designed to determine the sensitivity of field muskmelon to nicosulfuron, imazapic, fomesafen and bentazon. Eleven putative resistant populations and 1 sensitive population were used to evaluate the sensitivity of field muskmelon to these herbicides. Further, we analyzed the cross resistance and multiple resistance in field muskmelon plants. Among the 11 putative resistant populations, 10 populations evolved resistance to nicosulfuron, 6 populations were resistant to imazapic, and 4 populations evolved resistance to fomesafen, whereas none of the populations were resistant to bentazon. Moreover, field muskmelon has evolved resistance to the ALS-inhibiting herbicides nicosulfuron and imazapic, and to the PPO-inhibiting herbicide fomesafen. Fortunately, most of the resistance levels were low. The findings indicate that effective measures are needed to control resistant field muskmelon and avoid the further development of resistance in this plant.