Effects of yellow peach moth Conogethes punctiferalis egg age on parasitism and oviposition behaviour of four indigenous Trichogramma strains in China

Abstract

ABSTRACT The yellow peach moth, Conogethes punctiferalis (Guenée) has become a major insect pest in Huang-Huai-Hai summer corn region of China in recent years. Larvae directly threatens the yield and quality of corn by boring into corn ear and feeding. Currently, there are few studies to use the parasitoids, Trichogramma, to control the pest C. punctiferalis, so this study firstly evaluated the parasitism, suitability and oviposition behaviour of Trichogramma on C. punctiferalis eggs at different ages in laboratory. We found that C. punctiferalis eggs at different ages could be parasitised by four Trichogramma strains, but the number of parasitised eggs gradually decreased with egg age. Among them, the Xd strain of T. dendrolimi exhibited a better acceptance to old age eggs, which parasitised 12.8 host eggs within 24\u2005h. The percentage of female progeny of Xd strain was the highest among the four strains when young eggs were provided. Parasitoids took more drilling time on old eggs than that on young ones, however, the Xd strain took 37.07s, 36.60s and 44.27s on young, middle and old eggs, respectively, and with no significant difference. The current study has shown that the Xd strain of T. dendrolimi performed better on the parasitism, the acceptance to old age eggs, the host handing time and the suitability of progeny than other strains, indicating that this strain may be a potential biocontrol agent for C. punctiferalis.