Study On Occurrence,distribution,growth Limiting Ecological Factors And Chemical Control Techniques Of Ragweed And Giant Ragweed

Ragweed and giant ragweed were first found in Yili River Valley of Xinjiang in 2010,Since the invasion,it has seriously affected the local ecological environment and the development of tourism industry.The reason for the occurrence and distribution of the two species is not clear,In practice,there is a lack of safe and efficient chemical herbicide scientific application and efficiency reduction technology.Therefore,this study investigated the ecological factors of its occurrence and distribution,The ecological factors affecting its occurrence,distribution and growth restriction were analyzed;Field plot experiment was used,Screening of safe and efficient chemical herbicides,their concentration and control period should be carried out,And the synergist and herbicide synergism technology research,The purpose is to provide technical support for the scientific control,drug reduction and efficiency enhancement of ragweed and ragweed in Yili Valley of Xinjiang.The main results are as follows.(1)Ragweed and giant ragweed are mainly distributed in natural grassland,farmland and residential areas.The results of correlation analysis showed that there was a positive correlation between plant height and leaf number,between plant number and coverage,and a negative correlation between plant height and plant number,between plant number and leaf number.The results of principal component analysis showed that,Water source,altitude and ground humidity all reflect the important influence of light and humidity on the occurrence and distribution of giant ragweed,Therefore,the ecological factors limiting the occurrence,distribution and growth of giant ragweed are light and humidity.(2)Repeated measures analysis of variance showed,75%saflufenacil and glyphosate WG 60.0,90.0mL/667 m~2had the highest plant control effect and fresh weight control effect to ragweed,the following were 30%glyphosate AS 350.0,450.0 mL/667 m~2,48%triclopyr EC 278.0,417.0 mL/667 m~2,21%aminopyralid AS 20.0,25.0 mL/667 m~2,the lowest was 20%mesotrione SC 42.5,50.0 mL/667 m~2.Repeated measures analysis of variance also showed,21%aminopyralid AS 40 mL/667 m~2had the highest control effect of plant and fresh weight,which were 69.7%and 93.4%respectively after 45 d,the second was 21%aminopyralid AS 30.0,35.0 mL/667 m~2,which were 47.8%,86.4%and 51.7%,91.5%respectively after 45 d.(3)The results showed that,the control effect of giant ragweed was the best at 12 leaf stage,and the control effect could reach 100%at 45 days after treatment.When controlling ragweed at 20 leaf stage in grassland habitat,the control effect of 21%aminopyralid as 35.0 ml/667m~2strain was more than 50%.When Ambrosia trifida was in 4-and 8-leaf stage,the control effect was better in a short time,however,in the process of control,the ragweed in this period will sprout new plants,Therefore,it is suggested that the control should be carried out at 12 leaf stage to achieve the expected control effect.(4)The results showed that,21%aminopyralid AS 17.50 mL/667 m~2,75%saflufenacil and glyphosate WG 42.00 mL/667 m~2,the occurrence and damage of ragweed with plant height of 23 cm or so in May and12 cm or so in June can be effectively controlled by adding synergists,it is feasible to reduce the application rate by 30%,but the synergistic effect of different synergistic agents is different to some extent.In actual production,it is recommended to use the synergist Jijian 15.00 mL/667 m~2,the second is synergist Orange Peel oil 15.00 mL/667 m~2.