Advantages of diapause in Trichogramma dendrolimi mass production on eggs of the Chinese silkworm, Antheraea pernyi

BACKGROUNDTrichogramma dendrolimi Matsumura is widely used as a biological control agent for control of lepidopteran agricultural pests in China and can be successfully reared using the large eggs of the Chinese silkworm, Antheraea pernyi. In this study, biological parameters of diapaused, non-diapaused, and cold-stored T. dendrolimi were investigated for two generations on host eggs of A. pernyi under laboratory conditions. RESULTSThe cold-stored T. dendrolimi performed more poorly than diapaused and non-diapaused T. dendrolimi based on biological parameters. In the F1 generation, the non-diapaused T. dendrolimi had a higher emergence rate, longer longevity, and a lower proportion of deformed individuals than diapaused T. dendrolimi. In the F2 generation, the diapaused T. dendrolimi had a lower proportion of unemerged parasitoids than non-diapaused T. dendrolimi. However, the diapaused T. dendrolimi had a higher number of parasitized hosts than non-diapaused T. dendrolimi in both generations. In the F1 generation, the index of population trend (I) was found to be similar for diapaused (140.792) and non-diapaused (141.542) T. dendrolimi and was approximately 3.4 times that of cold-stored T. dendrolimi (41.698). In the F2 generation, the diapaused T. dendrolimi showed the largest I (146.791), followed by non-diapaused (136.859) and cold-stored T. dendrolimi (59.607). CONCLUSIONIn a 3-year augmentative field release from 2014 to 2016, diapaused T. dendrolimi showed effective parasitism on eggs of the Asian corn borer, Ostrinia furnacalis. These results indicated that diapaused T. dendrolimi can be an efficient alternative method for mass rearing of T. dendrolimi for long-term cold storage. (c) 2017 Society of Chemical Industry