Study On The Safety Of Herbicide On Stevia And Its Control Effect On Weeds In Field

Stevia planting areas in China belong to non-traditional planting areas,and weed damage is serious in seedling stage and growing stage,which is one of the main factors affecting stevia yield.At present,the main technology of weed control depends on chemical weeding.Based on the investigation of weed species in stevia field in Quzhou County,Hebei Province,the safety of 12 herbicides against stevia was determined by laboratory bioassay using 6 soil-sealing herbicides before seedling and 10 stem-leaf herbicides after seedling.Finally,the control effect of the herbicide on the main weeds in the field and the influence on the growth and development of stevia were studied through the field efficacy test,and the following research results were obtained1.Investigation of weed species in stevia field in the stevia planting base of Quzhou County,Hebei Province.The inverted"W"nine-point sampling method was used to investigate the weed species in stevia field.There were 23 species,23 genera,12families of weeds in stevia field,6 species,6 genera,1 family of grasses,and 16 species,16 genera,10 families of broadleaf weeds.2.The safety analysis of stevia herbicide,the indoor bioassay method,6 kinds of soil enclosed herbicides:33%Pendimethalin EC,24%Oxyfluorfen EC,36%Pendimethalin·Diflufenican SC,30%Diflufenican SC,41%Flufenacet SC and 30%Diflufenican·Flufenacet SC.6 kinds of stem and leaf herbicides:10.8%Haloxyfop-P EC,10%Quizalofop-P-ethyl SC,24%Clethodim SC,10%Fenoxaprop-P-ethyl SC,15%Fluazifop-P-butyl SC and 12.5%Sethoxydim SC.3.Six kinds of soil-sealing herbicides were selected,with three concentrations respectively,and sprayed before stevia transplanting.33%Pendimethalin EC 3000ml·hm^-2 showed significant comprehensive control effect,and had no inhibitory effect on stevia growth.4.Six stem-leaf herbicides were selected and four concentrations were set respectively.Spraying was carried out 30 days after stevia transplanting,and 10%Quizalofop-P-ethyl SC 600 ml·hm^-2 had significant effect on weed control and high safety on stevia.In this study,the control effect of soil-closed herbicide and stem-leaf herbicide on main weeds and the safety of stevia in stevia field were preliminarily explored.The aim of this study was to provide a basis for screening suitable herbicides in stevia field.