Efficiency of chemical and organic pesticides for Conogethes punctiferalis (Lepidoptera: Crambidae) in commercial chestnut and walnut fields

Abstract

Efficiency of pesticides for Conogethes punctiferalis in chestnut fields. • Current pesticides of C. punctiferalis could not kill its larvae inside of fruits. • Aerial spraying the pesticides for C. punctiferalis should be applied at optimal timing. • Chlorfluazuron 5 % was the best as an aerial application pesticide among pesticides in this study. Chestnuts and walnuts are ones of most important forest products in Korea. However, Conogethes punctiferalis has been increasingly causing economic damages to chestnuts and walnuts. Currently, its management is mainly relayed on aerial application of pesticides. To select pesticides of C. punctiferalis for aerial application, damage rate of chestnut and walnut fruits and death rate of C. punctiferalis were analyzed according to selected pesticides. Experiments were conducted during two years by randomly applying chemical pesticide (i.e., Chlorfluazuron 5 % in 2018 and Thiacloprid 10 % in 2019), organic pesticide (i.e., paraffin oil 8 % + plant extracts (90 %) from Styphnolobium japonicum , Melia azedarach , and Dysphania ambrosioides ), and no treatment (i.e., control) into an area which were divided into three from a whole commercial field. All pesticides used in this study could suppress damages of walnuts and chestnuts by C. punctiferalis . However, these pesticides could not kill their larvae inside of fruits. Thus, aerial spraying these pesticides for C. punctiferalis should be applied at optimal timing or slightly earlier than optimal timing. By considering honeybee toxicity, cost, and management efficiency, Chlorfluazuron 5 % was the best as an aerial application pesticide among these three pesticide in this study.