| Mythimna separata(Walker),of which eggs could be used for the reproduction of Trichogramma,has the advantage of its no geographic restrictions,short reproductive cycle,large production and low cost.How to achieve factory massively producing Trichogramma japonicum,the dominant parasitic wasp of rice aphids to control rice aphids,one of the main pests in rice producing areas has been one of directions of biological control research in China.In this paper,to develop the key technology of reproduction of T.japonicumas the main object of study with the factitious host eggs of M.separata(Walker)in order to provide theoretical bases for massively producing indigenous T.japonicum with M.separata(Walker)eggs.Main research results were as follows:1.Parasitism and development of T.japonicum on M.separata(Walker)with different UV irradition time.Through the analysis of compare among numbers of parasitism and emergency of T.japonicum on M.separata(Walker)with different UV irradition time,hatching numbers of M.separata(Walker)decrease evidently with longer UV irradition time.When UV irradition time were 20 min,30min,40 min,50min and 60 min,hatching numbers could be could be 0.36,0.16,0.17,0 and 0,but with no significant difference which could be less than the hatching numbers with 0min and 10 min.And then the highest parasitism number was 28.97 with 30 min UV irradition time,which was not no significantly different from one with 40 min but higher than the ones with the other treatment.The lowest parasitism number was 16.36 with 60 min UV irradition time which was significantly different from the other treatments.In conclusion,the optimal time of M.separata(Walker)wtih UV irradition should be 30min-40 min.2.Parasitism potential of T.japonicum on M.separata(Walker)based on the evaluation of life table.The life table of the experimental population for T.japonicum on M.separata(Walker)eggs under different temperatures was formed.The life table of experimental populations of T.japonicum on different eggs at different temperatures was prepared.R0,T,rm and ? of T.japonicum at 20?,25?,30?,33? were 22.5068,15.9999,0.1946 and 1.2148;31.9186,10,0.3463 and 1.4138;220.4936,8,0.3775 and 1.4587;7.662,6,0.3394 and 1.4141,respectively.At each temperature,the emergence of reached the highest level at the day.At different temperatures,the parasitic numbers of single female T.japonicum,the average longevity of female T.japonicum,and the emergence rate were significantly different.The parasitic numbers at 25? of single female of T.japonicum was significantly higher than the ones at other three temperatures,which was 32.88.The emergence rate decreased with increasing temperature,and there was no significant difference between emergence rates at 20? and 25?,which were reaching 95.11% and 94.34%,respectively.On the whole,when it was at 25?,the reproductive property parameters of T.japonicum on the eggs of the armyworm were higher than at the other three temperatures.It is recommended to use the M.separata(Walker)eggs to propagate of T.japonicum at the temperature 25? in massive production way.3.Effects of cold storage at different temperatures on the emergence rate of T.japonicumIn this paper,four refrigerating temperatures(2,5,8,10?)and eight time gradients(0,3,9,15,20,25,35,40d)were set and the emergence rate was used as an indicator to evaluate effects of the cold storage.The results showed that the emergence rate of T.japonicum decreased with the increase of refrigerating time,and the decrease range was also different when the temperature was different.The emergence rates of being refrigerated for 3d,9d,15 d and 20 d at 10? reached 94.01%,95.75%,96.17% and 90.47%,respectively,which were no significant difference between the treatments without being refrigerated,however were significantly higher than the rates at other refrigerated time.Under the same time of refrigeration(9d,15 d,20d,25 d,30d,40d)the emergence rates of different temperatures(8? and 10?)were significantly different,which were significantly higher than the ones of 2? and 5?.In summary,the emergence rate of T.japonicum which was being refrigerated at 20? or 10? for 20 d was not affected.It is recommended that the refrigerating temperature should be 8-10?and the refrigerating time should be 20 d in massive production way.4.Effects of refrigerating M.separata(Walker)eggs at different Temperatures on rates of T.japonicumIn this paper,four refrigerating temperatures(2,5,8,10?)and eight time gradients(0,3,9,15,20,25,35,40d)were set and the parasitic numbers and emergence rate was used as indicators to evaluate effects of refrigerating M.separata(Walker)eggs.The results showed that the parasitic numbers of T.japonicum on the eggs of M.separata(Walker)eggs were significantly decreased with the refrigerating time at each refrigerating temperature.When the eggs were refrigerated at 10? for 10 d and 9 d,the parasitic amount reached 29.21 and 30.90,respectively,which was not significantly different from that of non-refrigerated,but was significantly higher than that under the other refrigerating time treatments.When the M.separata(Walker)eggs were refrigerated within 9 days,there were no effects on the parasitization of T.japonicum.Under different cold storage conditions,the emergence rates of T.japonicum were significantly reduced with the prolongation of refrigerating time.When the eggs were refrigerated at 5?,8?,10? for 15 days,the emergence rates of T.japonicum was not significantly different from the blank control group.In summary of the parasitic amount and emergence rate indicators,it is recommended that the refrigerating time for the production of M.separata(Walker)eggs should not exceed 9d in massive production way. |
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