| Drosophila suzukii(Matsumura),is a destructive pest and native to the Asian countries that damages soft-skinned fruits.In recent years,it caused huge economic losses in Europe and United States Country.However,D.suzukii is not observed on large-scale in China owing to the restricted by natural enemies.Therefore,it is dire need to find and studied the most affective parasitic wasps or other natural enemies that can effectively control this pest.The main findings of the present study are as following:1.Two larvae parasitoids and two pupal parasitoids were identified.The two larvae parasitoids are Leptopilina japonica Novkovic and Kimura(Figitidae)and Asobara sp.(Braconidae);two pupal parasitoids are Trichopria drosophilae Perkins(Diapriidae)and Pachycrepoideus sp.(Pteromalidae).2.The fecundity and longevity of Trichopria drosophilae with high parasitism rate were studied.The results were revealed that the parasitic period of mated and unmated female parasitoids(36.90 ± 4.27 d,47.70 ±5.48 d)was longer than their oviposition period(26.6 ± 1.45 d,22.90 ±2.18 d),respectively;The parasitic rate of mated female parasitoids during the first 25 days was 59.24%,and 134.30 ± 7.14 off springs were produced in their lifetime.The parasitic rate of unmated femaleparasitoids in the first 21 days was 64.68%,and 114.80 ± 6.23 male off springs were produced in their whole life(parthenogenesis can only breed male off springs);The lifespan of mated and unmated female parasitoids providing hosts,as well as mated female parasitoids un providing hosts were 37.90 ±4.45 d,52.00 ±2.23 d and 71.60 ±4.39 d,respectively.The population parameters in the laboratory were obtained from the collected data.The reproductive rate(Ro)was 35.90,while the intrinsic growth rate(r)was 0.39,the weekly growth rate(?)was 1.47,and the generation time(T)was 9.29 d,and the doubling time(DT)was 1.80 d.3.The number of off springs in parasitoids when Trichopria drosophilae separately parasitic on three hosts of each 30 Drosophila suzukii,Drosophila immigrans and Drosophila melanogaster were 17.1,16.8,and 10.4,respectively.The number of off springs in parasitoids when Trichopria drosophilae selectively parasitic was 14.0,11.4,and 5.0,respectively.The results showed that Trichopria drosophilae was preferably parasitic on Drosophila suzukii,followed by Drosophila immigrans,and finally Drosophila melanogaster.4.The rapid and large-scale reproduction method of the Trichopria drosophilae was studied with Drosophila melanogaster as the host.The results showed that in the case of 25 pairs of Drosophila melanogaster breeding,50 female parasitoids were introduced,the average emergence of the parasitoids progeny in each insect tank was 1319.33,and theproportion of female was 53.44%,and this method is better.5.Parasitoids at different developmental stages after parasitization were refrigerated for 5 d,11 d,19 d,30 d,60 d,90 d at 7~9 °C.The results showed that the emergence rate decreased with the increase of refrigerating time in each developmental period.During the period of5~30 days of refrigeration,the emergence rate of parasitoids was the highest in the developmental period of 11 d after parasitization.In the refrigeration period of 60~90 days,parasitoids with developmental period of 4 days after parasitization can be survived,and parasitic wasps in other developmental stages can hardly be survived.Therefore,it is possible to select different development times for refrigerated preservation according to the requirements of the refrigerating time. |
PDF Full Text Request