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In the hope of obtaining insect resistant clones in Hibiscus syriacus L. flying aphid infestation and plant growth were investigated. Only one species, Aphis gossypii, was intensified in H. syriacus plant, and it was confirmed that H. syriacus plant was the winter host plant of Aphis gossypii. Two occurrance peaks, one of them is in May and the other is in October, were observed. The former occurred concurrently with the new shoot growth stage showing severe, and the latter showed weak responses. One-time insecticide spray in May showed no effect as compared to control. But 3-time sprays with 1 week interval before sprouting made the aphid population below 1 grade. One hundred and fifteen clones were selected as aphid free clones in severely contaminating season.
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