The effectiveness of releasing different Trichogramma species to control the Asian corn borer
Author of the article:WANG Lian-Xia1** LI Dun-Song2 LUO Bao-Jun1 ZHAO Xiu-Mei1 ZHENG Xu1 YUAN Ming1 JIANG Xiao-Jun1 HE Kang-Lai3***
Author's Workplace:(1. Qiqihar Sub-academy of Heilongjiang Academy of Agricultural Sciences, Qiqihar 161006, China;
Key Words:Trichogramma; Ostrinia furnacalis; mass release; control efficacy
Abstract:
[Objectives] To identify locally adapted Trichogramma species and determine the optimal date to release these to control the Asian corn borer (ACB), Ostrinia furnacalis (Guenée) in the Second Accumulated Temperature Zone of Heilongjiang Province. [Methods] Multiple releases of Trichogramma ostriniae, T. dendrolimi, and T. chilonis, were carried out to control of ACB in corn fields in Qiqihar in 2016 and 2017. The release regime included a first release of 15 000 wasps per hectare on the 30th of June and a second release of 30 000 wasps per hectare on the 5th of August. [Results] There were significant differences in the rate of parasitism on ACB egg masses among the three Trichogramma species released. The highest average parasitism rate (95.7%), 49.0% higher than that in control fields, was achieved by releasing T. ostriniae. The second highest average parasitism rate (74.1%) was achieved by releasing T. dendrolimi. The lowest average parasitism rate (69.7%) was recorded following the release of T. chilonis. There were significant differences among the different Trichogramma species released in terms of percentage of damaged plants, number of larvae, and tunnels per hundred stalks at harvest. The overall reductions in ACB abundance achieved by releasing T. ostriniae, T. dendrolimi, and T. chilonis were 78.1%, 66.2% and 60.2%, respectively. [Conclusion] T. ostriniae should be the first candidate for release to control ACB in this region. The optimal time for the first Trichgramma release should be the 30th of June.