Fruit and Leaf Damage by Conogethes punctiferalis (Lepidoptera: Crambidae) and Acrocercops transecta (Lepidoptera: Gracillariidae) in Walnut Orchards

Walnuts are one of the most economically important fruit trees in forestry. In walnut orchards, however, studies examining damage by insect pests are limited. This study was conducted to investigate the rate of damage caused by Conogethes punctiferalis to walnut fruits and by Acrocercops transecta to walnut leaves. In 2017, the change of damage rate (caused by C. punctiferalis) to fruits were investigated in Buyeo. In addition, we counted fruits and leaves damaged by two lepidopteran species in Gimcheon, Buyeo, Yeongdong, and Hwaseong. Damaged fruits steadily increased in abundance with fruit growth in Buyeo, and the highest number of damaged fruits was documented in late summer. The rates of damage caused by C. punctiferalis to fruits in Buyeo, Gimcheon, and Hwaseong were 22.1%, 20.5%, and 11.7%, respectively. Additionally, the rates of damage caused by A. transecta to leaves in seedlings (58.5% on average) were significantly higher than to those in older trees (11.2% on average), irrespective of the study location. In conclusion, this study showed that C. punctiferalis and A. transecta were serious pests affecting walnut fruits and leaves, respectively. Therefore, management methods for these insect pests need to be developed.