The yellow spotless ladybug (YSL), Illeis koebelei is a kind of aboriginal ladybug in Korea. YSL feed on the fungi and extraordinary prefer to powdery mildew (PM). This study was conducted to investigate the developmental characteristic and the biological control effect on the cucumber PM by the YSL from 2010 to 2012. YSL were detected on the 12 species of host plants infected with PM. and occurrence was observed from the early of July to the early of November in Gyeonggi area. The feeding amount of YSL on the cucumber PM was in order of 4th larva, adult, 3rd larva, 2nd larva and 1st larva. The optimum developmental temperature and photoperiod for YSL was 20∼25℃ and 16L:8D respectively. Three species of fungi were selected as the short term substitution feed for YSL. Control effect on cucumber PM under 2.5% of occurrence rate was linearly increased in proportion to increased numbers of 3rd larva were applied. Combination treatment of the fungal agent with YSL enhanced suppression of cucumber PM more than either agent used alone. The safety agricultural chemicals were selected harmless to the survival of larva and adult of YSL. The survival rate of pupae and adult was over 80% after storage at 10∼12℃ for 30 days. Five species of banker plant were selected for maintenance of YSL during growing season in greenhouse.

Biological Characteristic of Obolodiplosis robiniae and insecticidal activity of some insecticides against larvae of O. robiniae were investigated. Egg was in oval shape, and its color was light orange and became red when close to hatch. Length of the major axis and the minor axis of egg was 0.4 ㎜ and 0.1 ㎜, respectively. Larval color was milky and size was 2.6 ㎜. Pupa was deep brown and its size was about 3.2 ㎜. Wing and abdomen of adult was black and reddish, respectively. Size of female adult was about 3.3 ㎜, and larger than male adult. Number of eggs in the ovary was 192.3±50.7. First emergence was from late April to late May, and second from late May to late June. Third emergence was from late June to late July. Newly emerged adult escaped from soil, and second and third emerged adult escaped directly from gall of Robinia pseudoacacia leaf. Egg parasitoid was identified as Platygaster robiniae and parasite rate was 51.6%. Among test insecticides, imidacloprid 10% WP and thiacoprid 10% FL showed very strong insecticidal activity against larvae of O. robiniae at 48h later after treatment.