Abstract: The leafhopper Empoasca onukii Matsuda is a difficult pest to control. As a result, high dosages of insecticide are often used in tea plantations. To search for an effective alternative, applying microwave to reduce the population was investigated. The mortality rate of E. onukii adults by exposing the insects to microwave power at 0,100,200,400,500,600, or 800 W for 1 min was determined in the laboratory. Meanwhile, the pests were also irradiated at microwave of 0,100,200,300,400,500, and 600 W for 5, 7, 9, 11, 13, 15, and 17 min for an instant kill. Under the 1 min treatments, no significant differences were found on the insect mortalities in 16 d. The cumulated mortality was 64.4% on day 7 when 600 W microwave was applied. On the other hand, the same microwave power produced significant more instant deaths on E. onukii treated for 7-17 min than any other power levels. It killed the pests at the rates of 61.1%, 83.3%, and 87.8% in 13, 15, and 17min, respectively. Thus, an application of 600 W microwave for 13 min might be practical after further optimization on the treatment for a pest control measure on E. onukii.