Date of Award
Master of Science
This study was conducted to provide insight into the response of Achyranthes japonica to management tools in the form of complete shoot removal (clipping) and herbicide application at Cypress Creek National Wildlife Refuge (CCNWR) in southern Illinois. Field herbicide experiments indicate that A. japonica is susceptible to foliar applications of systemic, broad leaf herbicides. The removal of A. japonica by herbicide, however, did not allow for re-establishment of the surrounding plant community in years 2011 and 2012. Seedlings at node stage 3, 4 and 6 were able to regrow following complete shoot removal indicating that this species can sustain perennial growth when it develops three nodes and that the node stage at which plants were clipped did not affect their regrowth potential. In the greenhouse, A. japonica was able to regrow following complete shoot removal at the 3 node stage and the number of branches and apical nodes on a plant are the best predictors of the regrowth potential for this species. Achyranthes japonica's susceptibility to foliar applications of systemic herbicides in the greenhouse was high. Herbicide titration results indicate that of the six herbicides tested (2,4-D ester, triclopyr, glyphosate, aminopyralid, triclopyr+fluroxypyr, and aminopyralid+metsulfuron) triclopyr required the least amount of active ingredient to reduce the growth of A. japonica by 50% (GR-50). Results overall suggest that A. japonica reaches perennial growth by the time it has three nodes, making clipping as a management tool only successful if done before plants have developed three nodes. Achyranthes japonica perennial plants are highly susceptible to foliar applications of broad leaf systemic herbicides making them a good management tool in the field.
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