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Environmental Studies

Japanese Knotweed Monitoring Plan

Objective: Remediation of Japanese Knotweed (Polygonum cuspidatum), an invasive species imported from Japan as an ornamental plant; within a parameter of the south meadows floodplain at Goodwin College, East Hartford, CT.

Plan: To remove Japanese Knotweed through mechanical means by digging and pulling out roots and whole plant systems and to dispose of all parts to prevent further growth. This process must be repeated several times over the growing period to stump plant growth. We will use black plastic poly tarps to smother the roots to prevent further growth.

Types and Numbers of samples: Soil and groundwater samples should be considered for monitoring. For soil sampling we will use handheld (manually operated) sampling equipment such as augers. The Japanese Knotweed thrives in friable “crumbly” type soil. A soil sample can determine what other type of plant species we can replace in its place. After installation of phased wells in and around the parameter, water samples can be taken to determine contaminants, ph, conductivity, phosphorous, nitrogen, organic and bacteria material depending on lab costs. Sampling can be done either once a week or bi-weekly but should not last more than a month for the first phase. Based on the results of the first phase we could determine what the next round of sampling could be for. The sampling plan will be a simple random sampling. Appropriate testing methods will depend on the types of monitoring wells installed. One person can check samples for water sampling. Another person can check for soil samples.

Actual Costs: Are to be determined depending on the amount of samples taken, the equipment utilized to take the samples, transportation costs, and laboratory costs.

Data Quality Control & Objectives: We need to take statistical measures of accuracy, precision, defensible, reproducible, representative, useful, comparable, and complete samples. We can use GIS to interpret data into a data acquisition system. Quality control checks and QA will be implemented.

Implementation: Site location: South Meadows at Goodwin College campus, East Hartford, CT. Maps will be utilized for implementing project; topographic, soil, etc… We also need to be sure the project site can be accessible at all times. A timetable with a list of sampling graph dates and times, sample containers to be used for sampling, sample storage and preservation methods, sample transportation, and forms to be used for the samples to be taken.

Issues and concerns: Japanese knotweed rhizomes can grow more than 2 m into the soil and roots will expand to 15-20 m in length. The roots are fleshy to woody with a unique orange interior. (2005 Weston. Barney. Di Tommaso) It is difficult to treat Japanese Knotweed chemically and mechanically. Biological control is considered a viable future option. A chrysmeld beetle a rust fungus that is highly specific to Japanese knotweed is possible alternatives. (2005 Weston. Barney. Di Tommaso) The Japanese Knotweed Alliance, which is part of CABI (Center for Agricultural Bioscience International a not-for-profit science-based development and information organization), has a information video on theory web site that list three types of biological control.

  1. Conservation - The protection and maintenance of existing natural enemies.
  2. Inundative - The “mycoherbicide approach” The use of native pathogens for repeated application.
  3. Classical - The use of co-evolved (highly specific) natural enemies from the area of origin of the plant to be probed of self-sustaining control.

The most promising biological this group in England has discovered a psyllid called Aphalara itadori. It is native to Japan and the natural enemy of the plant. The insect lays its eggs on the plant and the nymphs when open will suck the sap from the plant (Japanese Knotweed Alliance,Cabi)

To read more about the project click here.

Out in the field

Click the images below to see the study and removal of Japanese Knotweed