Parasite Control Effect On Solidago Canadensis By Cuscuta Australis And Cuscuta Chinensis

Solidago canadensis is a kind of worldwide invasive weed from North America which have been invaded into Europe, Asia and Oceania, and coursed serious loss to the bio-diversity and agriculture of these areas. Nowadays the main preventive is Chemoprophylaxis or root out by manpower. Using parasitic plants to control invasive plants is deemed to be a new hot spot, this study is to use two kinds of high security indigenous parasitic plants named Cuscuta australis and Cuscuta chinensis to control Solidago canadensis. by testing nutrition and physiological index of the two parasitic plants and Solidago Canadensis under different level of factors like light, moisture, soil type, Allelopathy, parasitism preference, and evaluate the feasibility, applicability and influence of the two parasitic plants. The results are as follows:1 feasibility study(1) Allelopathy:Lixivium and extract of S. canadensis coursed slight restrain to the seeds of C.australis and C.chinensis, but no marked effect to .Allelopathy by S. canadensis coursed no marked restrain to the germination of C. australis and C. chinensis.(2) Enwind rate:rate of en winding by both C. australis and C. chinensis reached a so high level that large-scale seeding turned to be a feasible way.(3) Parasitism preference: C.australis and C.chinensis prefered to parasitize Leguminous crops and Compositae plants, especially the former to the Compositae plants. Gramineous weeds also could be parasitized. So legume farmland should be avoided to use the two plants.2 Applicability study(1) Condition filtrating:Light level is the most important factor following by moisture level and soil type. Both S. canadensis and the two plants grew very slowly under 30% of nature light; Germination rate of C. australis and C. chinensis decreased seriously under semiarid condition; soil type coursed no marked effect except for slight restrain to the germination rate of the two plants.(2) Parasitism experiment:Observation showed that C.australis and C.chinensis could parasitize all growth phases of S.canadensis; plants under 1.2 m of height showed more harm coursed by parasitism; chlorophyll, Photosynthetic Rate and Biomass of S.canadensis decreased greatly while MDA, Proline, Dissoluble sugar increased remarkably after parasitized.(3) Plot examination:seeds of C. australis and C. chinensis in All of 8 pieces of 1 X 1 plots reached more than 5% of germination rate after freezed for simulating hibernation; 28% of S. canadensis were parasitized by the contrast of only 18.27% of other weeds, sensitive distance of S.canadensis was more far than other weeds, which confirmed the two filial generation Cuscuta's persistent effect on S.canadensis.