Study On Introduction, Protection, And Bioecology Of Tiphia Vernalis Rohwer, Tiphia Popilliavora Rohwer

For the purpose of protecting the source of Tiphiidae wasps to control white grubs in China and also to help introducing the wasps into the United States to control Japanese beetle, entomologists from both countries worked together and conducted this cooperative research.Investigation conducted in Shandong and surrounding area demonstrated that the occurrence of Tiphiidae wasp species in Shandong were miscellaneous. Tiphia communis and Campsoneris annulata were dominating speciese locally. Study laterly showed that four species of Tiphiidae wasps could be considered to be used as for Japanese beetle biocontrol agents; they are T. vernalis, T. popilliavora, S.japonica, Campsomeris annulata. Among them T. vernalis, and T. popilliavora native host is Popillia quadriguttata that looks very similar to Popillia japonica in the morphologic characters. These two species were introduced into the United States in 20-30's last Century, and being regarded as the main target parasitoids.Study on developing techniques of mass rearing Tiphia vernalis Rohwer with the host of Japanese beetle revealed that the age of host white grub, nutrition status of female wasp and population density were the key factors to influence the reproduction rate. Ratio of cocooning of Tiphia larvae that parasited on the third instars white grubs was 2.87 times higher than on the second instars white grubs. 80% offspring wasps emerged from the second instars white grubs was male compare with that of 60% was female emerged from the third instars white grubs. The parasitic efficiency become lower when the density of the female wasps getting higher. The highest coefficient of mutual interference appeared during the ovipositing peak. The average number of eggs and cocoons collected from each female wasp increased when collecting frequency became high.Study results indicated that T. vernalis could occur in the tested environment frequently and not move too far especially Liriodendron tulipifera L. existed.Searching ability of two Tiphia species to host grub was significant different, T. vernalis stronger than T. popilliavora and American geographical strain of T. vernalis stronger than Chinese Shandong strain.Plant preference also is the edaphic parasitoids main behavior. Study conducted in corn-peanut and sweet potato-peanut fields showed that the first flying was a escape style, the second fly preferred landing on corn field and the third time landing preferred landing on peanuts field. Diapause is the mechanism of adjusting such living span match. Sampling continually during a year indicated that T. vernalis lasted diapause period about 120d per year, but T. popilliavora could last for 240d. The distribution of the diapause period in different seasons between the two Tiphia was different.Diapause period of T. vernalis started from summer July till early winter December, T. popilliavora started from October to July next year. Diapause of T. vernalis were not affected by host diapause status, but T. popilliavora apparently greatly influenced by its host diapause status. The hemolymph of non-diapaused host played a role of stopping T. popilliavora enter diapause, and the function became stronger if increased dosage.Three zones for Protecting Tiphiid wasps surviving and reproducing were established in the areas of Laiyang, Haiyang and Rizhao Shandong Province. Investigation showed that the resource of Tiphiid wasps had been well protected by prohibiting applying insecticide, planting nectariferous plants, protecting wasp cocoons over winter etc.The main points concluded from this research were that introduction of natural enemies from non-original countries to control invasive pest insects could achieve success too; Bioecology can be used to evaluate if the international introduced natural enemies can establish stable population; Edaphic dwelling parasitoids showed significant preference to plant environment; The impact capacity of introduced parasitoids to non-originated target host can greatly increase with the process of adapting new environment; The key fact...