Influence of cold-storage of Corcyra cephalonica eggs on the offspring quality of Trichogramma japonicum and Trichogramma ostriniae
Author of the article:ZHOU Shu-Xiang1** LU Xin1 *** LI Li-Juan1 ZHANG Guo-Hong1 MAO Gang2SUN Kang-Na2 DING Yan1 CHAN
Author's Workplace:1. Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, China; 2. Subsidiary Company of Biological Control, Jinong Hi-Tech Co., Ltd. Gongzhuling 136100,China
Key Words: Corcyra cephalonica eggs; cold storage; Trichogramma; offspring quality
Abstract:
[Objectives] To investigate the effects of
cold-storage of Corcyra cephalonica eggs on the offspring quality of Trichogramma
japonicum and T. ostriniae. [Methods] C. cephalonica eggs were stored at 0,3,6 and 10 ℃ for
0, 3, 5, 7, 10, 15, 20, 25, 30
and 40 days, and the effects of feeding eggs subject to these treatments on the
parasitic capacity of Trichogramma sp.
offspring, adult emergence rate and the proportion of females in the second
generation were recorded and compared.The product of the number of parasitized eggs, emergence rate and
proportion of females was used to evaluate the quality of Trichogramma offspring. [Results]
Refrigerating C. cephalonica eggs had
significant effects on the parasitizing capacity of T. japonicum and T.
ostriniae offspring. The effect was least apparent when eggs were
refrigerated at 4 ℃ and eggs
refrigerated at this temperature had the least effect on the oviposition rate.
Eggs that had been refrigerated for 20 days had no clear effect on the
oviposition rate. Oviposition of wasps raised on eggs refrigerated at 1 ℃ decreased the fastest, eggs
refrigerated for 3 days for T. japonicum and 5 days for T.ostriniae significantly
reduced oviposition rates of both species. Clear differences were also observed
in the emergence rate and proportion of females in the second generation,
however, the emergence rate of wasps produced by eggs refrigerated for 30 days
was still above 70%, and the proportion
of females was still above 75%. [Conclusion] Refrigerating C. cephalonica eggs at a
suitable temperature for a certain period of time had no significant
effect on the quality of offspring produced by T. japonicum and T. ostriniae.
The optimum temperature for refrigerating eggs was 4 ℃ and the quality of Trichogramma sp. offspring was decreased
by less than 50% by 30 days of refrigeration.