The Biological Characteristics And Artificial Rearing Of Diachasmimorpha Anshunensis(Ao & Zheng)

Zeugodacus tau(Walker)is a key quarantine object of fruit and vegetable pests worldwide.In recent years,the pest has causing great economic losses and become more and more serious at home and abroad.Therefore,it is more urgent to study and control the pest.Ao Guofu et al.discovered a new larva dominant parasitoid of Z.tau and named it as Diachasmimorpha anshunensis(Ao & Zheng).In this paper,the biological characteristics and artificial rearing technology of D.anshunensis were studied,which filled the gap of the study of the native larval parasitoid of Z.tau.D.anshunensis took 7 days to complete emergence,of which the third day was the peak period of emergence,and the daily from 8:00 to10:00 was the peak period of emergence during a day.During the oviposition period,the oviposition activities occurred from 8:00 to 22:00every day,and the peak period of oviposition occurred from 14:00 to18:00.In the temperature range of 16 ℃ ～28 ℃,the development period of D.anshunensis was shortened with the increase of temperature.The development period of egg-larva was about 7～14 days,and that of pupa was about 6～17 days.Males usually emerged 2 days earlier than females.D.anshunensis could spawning within 1～12 days after emergence.and the peak period of oviposition was days 2 to 7 after emergence,on the 3rd day,the peak spawning volume reached to 18.71 per female.The average spawning volume was 116.1 per female during its lifetime.The proportion of female eggs is higher,when D.anshunensis lays eggs at 3to 6 days of emergence,especially on the 4th day after emergence,the proportion of female eggs of D.anshunensis is the highest,at 70.38%.D.anshunensis could parasitize the larvae of Z.tau,Bactrocera cucurbitae(Coquillett)and Bactrocera dorsalis(Hendel).In nonselective trials,when D.anshunensis parasitized Z.tau,the parasitism rate and emergence number were significantly higher than those of parasitism B.cucurbitae and B.dorsalis.Although it was almost impossible to successfully parasitize B.dorsalis,the lethality rate was significantly higher than that of Z.tau and B.cucurbitae.In the selective trials the selection coefficient for Z.tau larvae was 0.7893 and indicating a significant preference.D.anshunensis could parasitize the larvae of Z.tau at any day-age.In the non-selective experiment,when D.anshunensis parasitized 3 and4-day-old larvae of Z.tau,the parasitism rate,emergence number,progeny female ratio,lethality rate and generation period of progeny were better than those of 1 and 2-day-old larvae.Therefore,the 3 and 4-dayold larvae of Z.tau were more suitable for the growth and development of D.anshunensis.Selective experiments indicated that D.anshunensis preferred to parasitize 3 and 4-day-old larvae of Z.tau,with the selection coefficients were 0.4320 and 0.5416,respectively.D.anshunensis parasitized Z.tau larvae.When the P&P ratio was 1∶40,the parasitism effect optimized with the increase of parasitism time within 0～8 h.However,there was no significant change in parasitism rate,emergence number and progeny female ratio within the time range of8～24 h.Therefore,the optimal parasitism time is 8 h,which not only saves time but also reduces the probability of parasitism.During the temperature of 16 to 28 °C,the lifespan of adult D.anshunensis decreases with the increase of temperature,and the life expectancy decreases sharply at 28 °C.D.anshunensis had the highest parasitism efficiency at 22 ℃ and 25 ℃.At the temperature of 16～28 °C,with the increase of temperature,the generation period was also shortened,and the generation period was the shortest at 28 °C.However,the emergence rate of parasitoids increased firstly and then decreased with the increase of temperature,The emergence rate reached the highest at 25 ℃,and reduced to 30.06% at 28 °C.Based on the above conclusions,the most suitable temperature range for D.anshunensis is 22 to 25 °C.Under different nutritional conditions,the longevity of D.anshunensis adults was 10% honey water > honey > water > control.The parasitism rate,emergence number and progeny female ratio were in the order of honey > 10% honey water > water.And there was no significant difference in each index when feeding 10% honey water and honey,which was significantly higher than that of water and control.Therefore,D.anshunensis could be fed directly with honey during rearing.Based on the above conclusions,the artificial rearing of D.anshunensis was studied,and the feeding flow chart was designed.A stable experimental population of D.anshunensis has been established through this rearing technique,which provides a possibility for application in the field to control Z.tau.