| Agrilus planipennis Fairmaire (EAB) is an important destroyed wood-boring beetle attacking ash trees, and natural distributed northeast Asia. In recent years, it spread American and Canada. At present, this pest outbreak domestic and abroad, therefore, lead to enormous economic and ecology damage.In order to use natural enemies control EAB, the biological of enemies were studied. The super-cooling point and freezing point, in overwintering, of Spathius agrili Yang and Tetrastichus planipennisi Yang were determined. Scleroderma pupariae Yang et Yao was a new species and its biological, behavior and rearing techniques were researched. The mainly work and results of this paper are as follow:Results indicated that the super-cooling point and freezing point of EAB were ranged from -26.38 to -23.04℃and from -21.72 to -11.64℃respectively. The super-cooling point and freezing point of S. agrili were -26.28℃and -22.50℃, and T. planipennisi were 24.48℃and -21.87℃respectively. According to local climate that we predicted low temperature in winter is a little influence to their overwintering population.S. pupariae, ectoparasitoid of emerald ash borer (EAB) pupa, is a new effective natural enemy to EAB. It has 5 generations a year, and the generations overlaps heavily. Natural parasitod rate was 13.9%. The female adults average longevous were about 27.38±0.43 days without any nutrition supplementation and male adult were about 12.43±0.35 days. The sex ratio(♀:♂) was about 18.9~49.5:1. The female alate rate was different in every generation, and the rate in first generation was higher than in any other generation, it could reach 56.6%. Wasps parthenogenesis was observed without amphimixis, and their generations were all males.The development threshold temperature and effective accumulated temperature of S. pupariae were examined in room temperature. Results showed that the development threshold temperature of egg, larval, pupal stages and the whole generation were 16.89±0.79, 17.03±1.42, 16.90±1.68 and 15.31±0.47℃, respectively. The effective accumulated temperatures for these stages were 33.82±4.13, 49.11±7.93, 128.88±27.87 and 277.00±14.15 degree-day, respectively. According to local climate we predicted that this wasp may produce 4.75 generations one year, which was consistent with the practice. Host range of S. pupariae were determined in laboratory. The results showed that the wasp had a wide host range, including larva of EAB, Agrilus viduus, Agrilus mali, Agrilus zanthoxylumi, Agrilus lewisiellus, Falderman gebleri, Tenebrio molitor, Anoplophphora glabripennis, Chilo luteellus, Oatrinia orientalis, stenhomalus complicates, and another long-horned beetle. Pupa of EAB, Agrilus mali, Tenebrio molito and Chilo luteellus. The behaviour of S. pupariae was very complicated. The storage techniques and searching mechanism of S. pupariae were studied. Results indecated that wasps had stronger ability to search and attack the hosts, and its search mechanism possibly by identifying the hosts frass smell and had no relations with the smell that host larva sent out. The emergence rate was no more than 10 percent of the cocoon after stored 74 days in 8±2℃. After stored in 8±2℃for 78 days, male adults were all dead, and the death rate of female adults was 5.0~41.7 percent by using the water to keep humid, but without such condition, the death rate of female adults was 0. Low temperature storage had no significant difference in contrast to storage under room condition on their generations between oviposition and emergence number.The artificial rearing techniques were also researched. The results showed that female adults oviposited 3~5 times in their lifetime, and average emergence wasps were 32.9±1.2, in using pupa of EAB as host. The rearing method which inoculated one wasp or two to the pupa in the tube was studied, and the results indicated that the amount of propagation with the former method was more than the amount with the latter one. The amount of oviposition and emergence with the treatment to host by alcohol had no difference with the control group. |
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