Evaluation Effect On Bradysia Odoriphaga And Optimization Of Feeding Prey Of Lasioseius Japonicas

Bradysia odoriphaga is an important pest of onion and garlic.Its larvae are commonly called leek maggots,like eating the stems and leaves of leek.In recent years,with the rapid development of the agriculture of facility agriculture in north of China,the environment is suitable for the development of B.odoriphaga in our country,which has serious damage to the growth and reduces the yield of the leek,caused serious economic loss.At present,chemical control is the main control management,less research on biological control,improper use of pesticide often led to leek pesticide residues and other problems.Therefore,the biological control and related studies of B.odoriphaga are urgently needed.Lasioseius japonicus,a newly recorded species in China,is also a soil mite species with great potential ability of predation,and has broad application prospects in biological control,it has a broad application prospect in biological control.In this study,the predation ability of L.japonicus to B.odoriphaga,and the predation preference of different insect states,determined under indoor conditions,and established the sexual life table of L.japonicus feeding on B.odoriphaga.And determined the toxicity of the commonly used B.odoriphaga pesticide to L.japonicus,and the appropriate food source of L.japonicus was screened,providing a theoretical basis for the prevention and control of L.japonicus.This study can provide basic data for the prevention and control of L.japonicus and has obvious application value for reducing the use of chemical pesticides.The main results are as follows:1.Through the study on the functional response of L.japonicus on B.odoriphaga,it was found that the functional response of the mite on B.odoriphaga was Holling II type,The numerical reaction equation isNa=1.0353No（1+0.05No）,the attack rate to leek maggots is 1.035,and the processing time is 0.049 day.It had a strong feeding effect on the initial larvae of B.odoriphaga.2.Through the study on the preference of larva,nymph and adult mites to each state of B.odoriphaga.The results showed that larva had a higher preference to feed on B.odoriphaga eggs.Nymph mites showed the high feeding preference on B.odoriphaga egg and the first instar larva.The preference of female and male adult mites to B.odoriphaga is:first instar larvae>eggs>second instar larvae,do not feed on pupae.3.Through the study on Life Table of L.japonicus feeding on B.odoriphaga,the normal generation growth and development of L.japonicus can be achieved feeding on the first instar larvae or the egg of B.odoriphaga or a mixture of both.The preadult period of the L.japonicus was longest feeding on B.odoriphaga eggs.When feeding on mixed preys,the average spawning amount per female was 3.5,and the average spawning period was 6.5d.The intrinsic rate of increase,finite rate of increase and mean generation time were 0.097 d^-1,1.34d^-1and 18.37 d,respectively.L.japonicus could maintain the normal growth,development and reproduction of the population.4.The safe and low toxic agents were selected by the determination of indoor sensitivity of the L.japonicus to clothianidin,lambda-cyhalothrin,thiamethoxam,phoxim,sophocarpidine and imidacloprid.The order of the virulence of the tested insecticides to the choriosurium japonicus was:lambda-cyhalothrin>clothianidin>thiamethoxam>phoxim>sophocarpidine>imidacloprid,and it was found that imidacloprid was safe to L.japonicus.5.Through the comparative study of the preference of to alternative prey,it was found that there were significant differences in the preference of the mite to different prey with the extension of time.At 24h,the order of predation preference was Drosophila melanogaster eggs>B.odoriphaga first instar larvae>Tyrophagus putrescentiae protonymphes>Musca domestica eggs>Pyralidae Latreille eggs>Sitotroga cerealella eggs;at 48h,the order of predation preference was D.melanogaster eggs>T.putrescentiae protonymphes>M.domestica eggs>B.odoriphaga first instar larvae>P.Latreille eggs>S.cerealella eggs;at72h,the order of predation preference was D.melanogaster eggs>B.odoriphaga first instar larvae>T.putrescentiae protonymphes>S.cerealella eggs>M.domestica eggs>P.Latreille eggs.At 24h,48h and 72h,it was found that the mite had the largest preference for D.melanogaster eggs.In addition,after the domestication of the Sitotroga cerealella eggs within72h in this experiment,the preference of the mite was enhanced.6.Through the study on the life table of L.japonicus feeding on alternative preys,when mites fed on D.melanogaster,r is 0.261d^-1,R0 is 57.761,λis 1.3d^-1,T is 15.49d;By contrast,r is0.157d^-1,R0 is 20.957,λis 1.17 d^-1,T is 19.408 d when fed on S.cerealella.In addition,the life expectancy and population growth trend of the L.japonicus were simulated based on the above two alternative prey.The results showed that the results of feeding on the eggs of Drosophila melanogaster were more beneficial to the growth and reproduction of L.japonicus population.