Safety Evaluation Of Eight Herbicides On Suaeda Glauca And Two Natural Enemies

In our research group previous study,We had found Suaeda glauca Bunge has protective effects on Hippodamia variegata Goeze and Syrphus corollae Fabricius.In practice,herbicides are widely used to prevent malignant weeds on the ridges and wide application of chemical herbicides in cotton field made the herbicide enter into non-cotton field habitat by many ways and affect the communities of S.glauca Bunge.Eight herbicides were applied to the concentration areas of S.glauca Bunge according to the recommended concentration.The effects of eight herbicides on S.salsa Bunge and their insect communities had determined.The effects of herbicide on the safety of natural enemies were determined by spraying herbicides on H.variegata Goeze and S.corollae Fabricius with spray tower.Conclusion as below:1.The results showed that?Bensulfuron methyl30%,carfentrazone-ethyl8%??and?florasulam3%,carfentrazone-ethyl6%?caused wilting and seriously affected S.glauca Bunge normal growth.Fluroxypyr,Oxyfluorfen,Quizalofop-p-ethyl affect the normal growth of Suaeda salsa,Haloxyfop-P-methyl,Clethodim,Quizalofop-p-ethyl have a small impact on S.glauca Bunge and it is safe to S.glauca Bunge.Haloxyfop-P-methyl has little effect on the insect community of S.glauca,and Oxyfluorfen and Fluroxypyr has great effect on the insect community of S.glauca Bunge.Other 5 herbicides reduced the number of insect in S.glauca Bunge community,but had little effect on the structure of insect community.2.Eight herbicides have no significant effects on the egg hatchability,pupal emergence rate and adult survival rate of H.variegata.The survival rates of the 3^rdd instar larvae treated with Quizalofop-p-ethyl,Tribenuron-methyl,Fenoxaprop-p-ethyl were significantly lower than that of the control group.But there were no significant differences in larval survival rates of Haloxyfop-P-methyl,Floazifop-p-butyl,Clethodim,Fluroxypyr,Oxyfluorfen treatments comparing to control group.After eggs were treated by Haloxyfop-P-methyl and Oxyfluorfen,no significant effect was found on developmental durations of eggs and the following stages?larvae and pupae?,survival rates of each stages and pupae weight,except the significantly reduced larval pupation rate in Haloxyfop-P-methyl treatments.There was no significant effect on the growth and development of 3^rd instar larvae treated with Haloxyfop-P-methyl and Oxyfluorfen.The study confirmed that the 8 eight herbicides were relatively safe for H.variegata with no obvious toxic and negative effects.3.Eight herbicides had no significant effect on the S.corollae Fabricius's hatchability of eggs,the survival rate of 2^nd instar larvae and adult,pupal emergence rate.Spraying herbicide at the recommended concentration is relatively safe for eggs,larvae,pupae and adults.After spraying herbicides on the pupae of S.corollae,there were no effect on the pupal period,the deformity rate of adults treated with Clethodim increased significantly,and the other seven herbicides had no significant effect on the pupal normal emergence.Eight herbicides are safe to S.corollae,Clethodim has some effect on pupa emergence.Haloxyfop-P-methyl was safe for S.glauca Bunge and had little effect on the insect community.The other seven herbicides reduced the number of insect community individuals,but had little effect on the community structure.The herbicide had no direct killing effect on all insect states of S.corollae and H.variegata,but some herbicides have an effect on the normal emergence of pupae of S.corollae Fabricius and the rate of pupae of H.variegata.On the whole,herbicides are safe for S.corollae and H.variegata.