The damaged branches of Agrilus mali were collected from Yining city, Ili Kazakh autonomous prefecture, Xinjiang provience, China on June 26, 2015. The larvae and pupae were striped out from the damaged branches at Laboratory of Forest Pest Biological Control. Larvae, pupae and some new eclosion adults without food were collected and stored in centrifuge tube, followed gut dissecting immediately. The remaining new eclosion adults were reared with fresh leaves of different apple tree, Malus halliana Koehne and Malus pumila Miller, in a artificial climate chamber at 25±1°C, 70±5% relative humidity and a photoperiod cycle of 16/8 (L/D). The experimental feeding period was, about 20 days to ensure the formation of intestinal microflora from July 4, 2015 to July 24, 2015. Twenty individuals of each sample were manually selected and gut dissection was performed within 4 h.