[Relationship between occurrence of Dryocosmus kuriphilus and development of cecidum]

Dryocosmus kuriphilus is one of the most important pests on chestnut in China, and cecidum is the jeopardized result of Dryocosmus kuriphilus. Under natural condition, the growth status of different cecidum of Dryocosmus kuriphilus was differed, and the weight of individual cecidum was submitted to normal distribution. The zooecium number was positively related to cecidum quality and volume. For three different varieties of chestnut, their resistance to Dryocosmus kuriphilus were different, and the order was Chushuhong > Mifengqiu > Ershuizao. Torymus sinensis Kamijo was the dominant natural enemy. The cecidum-parasitized ratio was 72.7%, and the zooecium-parasitized ratio was 24.06%.