Effects Of Herbicides On Functional Weeds And Insect Communities

Our previous investigation found that in non-cotton field habitats.Acroptilon repens(L.)DC.,Glycyrrhiza uralensis Fisch.,Suaeda glauca(Bunge)Bunge,Sophora alopecuroides L.,Apocynum venetum L.,Sisymbrium loeselii L.are functional weed bands with potential conservation ability and can provide sufficient survival and population growth space for natural enemies.However,the realization of protective biological control through functional plants still faces a series of problems,and the use of inactivated herbicides in production removes functional weeds together with some other weeds.The use of chemical herbicides in crop fields also affects the functional weed communities in non-crop habitats.For this reason,this study investigated the effects of herbicides on the growth and habitats of six functional weeds by applying different types of selective herbicides at the seedling and establishment stages,with a view to screening selective herbicides that can both protect functional weeds and prevent malignant weeds in agricultural fields,so as to provide reference for the protection of functional plants with potential natural enemy conservation ability,and further promote the ecological regulation of pests and the implementation of protective biological control.The main research results are as follows :(1)Effects of herbicide application at seedling stage on functional weedsThe application of Haloxyfop-methyl at seedling stage of functional weeds was safe to A.repens(L.)DC.and effective in controlling Kochi scoparia(L.)Schrad.and Galium spurium L.,the control effects were higher than 60%.Oxyfluorfen was relatively safe,and could effectively control Convolvulus arvensis L.,K.scoparia(L.)Schrad.,Descurainia Sophia(L.)Webb ex Prantl and G.spurium L.,with the control effects higher than 65.00%.Pinoxaden is safe and effective in controlling C.arvensis L.and G.spurium L.with control effects of 60.00% and 100.00%,respectively.The Haloxyfop-methyl was safe to G.uralensis Fisch.and effective in controlling Gramineae weeds with the control effect of 40.24%.Fomesafen was safe and could effectively control C.arvensis L.and S.alopecuroides L.,and the control effects were higher than 50.00%.Trifloxysulfuron sodium is safe and effective in the control of C.arvensis L.,and the control effect is 52.08%.Haloxyfop-methyl was safe to S.glauca(Bunge)Bunge and could effectively control Gramineae weeds,with the control effect of 65.18%;Pinoxaden was safe to S.glauca(Bunge)Bunge and could effectively control Gramineae weeds,G.spurium L.and Lepidium perfoliatum,and the control effects were all higher than 40.00%.All the treatments were relatively safe to S.alopecuroides L.and could effectively control C.arvensis L.and K.scoparia(L.)Schrad.,and the control effects were higher than40.00%;Haloxyfop-methyl was safe to A.venetum L.and had more than 60.00% efficacy against Gramineae weeds and G.spurium L.,while Oxyfluorfen was safe to A.venetum L.and had 50.24% and100.00% efficacy against Gramineae weeds and G.spurium L.(2)Effects of herbicide application at adult stage on functional weedsBased on the survey results in 2020-2021,the application of Oxyfluorfen at the adult stage of functional weeds was safe to A.repens(L.)DC.and could effectively control Atriplex centralasiatica Iljin,with the control effect of 50.00%.Trifloxysulfuron sodium and Fomesafen were safe to A.repens(L.)DC.and could effective against C.sibiricum Willd.And S.glauca(Bunge)Bunge with control effects of56.25% and 100.00%,respectively.Fomesafen is relatively safe to G.uralensis Fisch.and could effectively control Chenopodium glaucum L.,Sonchus oleraceus L.and K.scoparia(L.)Schrad.and the control effect is higher than 80.00%.Pinoxaden and Trifloxysulfuron sodium were safe to G.uralensis Fisch.and could effectively in the control of K.scoparia(L.)Schrad.,and the control effects were higher than 40.00%.Pyrimazinamide is relatively safe to S.alopecuroides L.and can effectively control the K.scoparia(L.),the control effect is 75.00%;Fomesafen has little effect on the growth of S.alopecuroides L.,and can effectively control S.oleraceus L.,C.arvensis L.and C.glaucum L.,the control effect is higher than80.00%;Desmedipham is safe to A.venetum L.and can effectively control Gramineae weeds and C.sibiricum Willd.,the control effect is higher than 55.00%;Haloxyfop-methyl and Oxyfluorfen were relatively safe to S.loeselii L.(3)Effects of Herbicides on Natural Enemies Community in Functional Weed HabitatBased on the survey results from 2020 to 2021,Haloxyfop-methyl and Pinoxaden were safe to natural enemy communities in the habitats of A.repens(L.)DC.Fomesafen,Pinoxaden and Desmedipham were safe to natural enemy communities in G.uralensis Fisch.habitats;Haloxyfop-methyl was safe to natural enemy communities in the habitats of S.glauca(Bunge)Bunge;Haloxyfop-methyl,Pyroxsulam,Trifloxysulfuron sodium,Pinoxaden and Desmedipham were safe to natural enemy communities in the habitats of S.alopecuroides L.;Oxyfluorfen and Pinoxaden were safe to natural enemy communities in the habitats of A.venetum L.;Oxyfluorfen was safe to natural enemy communities in the habitats of S.loeselii L.In summary,Haloxyfop-methyl was safe to the plants of A.repens(L.)DC.and S.glauca(Bunge)Bunge,and was safe to natural enemies in their habitats.Fomesafen is safe to G.uralensis Fisch.and natural enemies in their habitats;Pyroxsulam and Pinoxaden were safe to S.alopecuroides L.and natural enemies in their habitats;Haloxyfop-methyl and Oxyfluorfen were safe to A.venetum L.and S.loeselii L.,and were safe to natural enemies in their habitats.