Abstract: In order to explore the optimal biological control technology of tea aphid （Toxoptera aurantii Boyer）, the field control and colonization of Coccinella septempunctata and Harmonia axyridis to the tea aphid were studied by releasing egg pieces of these two predatory ladybirds. The results showed that the Toxoptera aurantia control effect reached the best 15 days after releasing the ladybug egg mass, and the control effect of Coccinella septempunctata and Harmonia axyridis were 73.48% and 74.35%, respectively. Then it gradually decreased, but remained above 60%. There was no significant difference in the control effect between the two ladybugs in the Toxoptera aurantii. The field hatching rate of Coccinella septempunctata egg mass was 54.13% in the field, and that of Harmonia axyridis egg mass was 58.87% in the field. The released ladybugs can be detected within 30 days of the release of the egg card, and the number of Harmonia axyridis was slightly more than that of Coccinella septempunctata. However, there was no significant difference in the number of all the other forms except that the number of Harmonia axyridis pupae was significantly higher than that of Coccinella septempunctata pupae.

Key words: Coccinella septempunctata, Harmonia axyridis, Toxoptera aurantii, biological control