The effect of the ionization energy on the common house mosquito, Culex pipiens, pupa was investigated as the hatching rate, longevity and detoxification enzyme activity. The longevity of adult emerging in the pupa decreased depending on the exposure dose of Gray (Gy) in Cx. pipiens. The hatching rate of the F1 generation egg derived from Cx. pipiens pupa treated up to 70 Gy did not show any difference with the control, but the eggs did not hatch 100% at 120 Gy exposure. These results showed that Cx. pipiens was sterilized at 120 Gy. Several detoxifying enzyme (GST, non-specific esterase and MFO) activity of Cx. pipiens adult emerged from pupa irradiated with 120 Gy was investigated. The difference in activity was observed in female than in male irradiated with electron beam. As a result, electron beam irradiation seems to affect enzyme activity as well as induce infertility of Cx. pipiens.

The present study evaluated the susceptibility of field populations of Plutella xylostella and Spodoptera exigua larvae to four diamide insecticides—chlorantraniliprole, cyantraniliprole, cyclaniliprole, and flubendiamide. All the four diamide insecticides induced 100% mortality in the populations from Seongju (SJ) and Geochang (GC) when treated at a concentration recommended for P. xylostella. However, a very low insecticidal activity was observed in the population from Pyeongchang (PC) with 42.3% 3 d after treatment with chlorantraniliprole. Further, the populations of S. exigua from Cheongju (CJ), Jindo (JD), and Yeonggwang (YG) were not completely controlled by the 4 diamide insecticides. A comparison of susceptibility of S. exigua larvae to chlorantraniliprole between 2014 and 2017 showed that chlorantraniliprole induced 100% mortality in all populations in 2014, whereas a very low insecticidal activity was observed among the populations in 2017. This study can serve as a basis to control pests effectively using diamide insecticides.

The susceptibility of the Frankliniella occidentalis and Frankliniella intonsa was evaluated using 46 commercial insecticides. There were 10 kinds of insecticides as benfuracarb, chlorfenapyr, spinetoram, spinosad, abamectin + chlorfenapyr, abamectin + emamectin benzoate, chlorfenapyr + clothianidin, chlorfenapyr + imidacloprid, clothianidin + spinetoram and dinotefuran + spinetoram, which showed more than 90% mortality against both thrips, F. occidentalis and F. intonsa. Since the F. intonsa is more susceptible than F. occidentalis, it is considered that both thrips can be controlled by insecticides that show insecticidal activity on the F. occidentalis. The effect by the elapsed time after treatment of 10 kinds of insecticides was analyzed as LT50 and LT95 values. Benfuracarb was the fastest in 4.3 h (LT50) and 14 h (LT95), and spinetoram showed the most late time at 13.5 h (LT50) and 62.3 h (LT95), respectively.