As you all know, we (the joint TLPA – TLA Eurasian watermilfoil team) chemically treated a number of EWM patches last fall. Inconveniently, we then must wait until mid-summer of the following year in order to judge the effectiveness of that treatment. So finally last month, we got in the boat and revisited our treatment sites.
In summary, there was one location that responded amazingly well to the treatment (Alden Harbor) and one location that did not seem to respond at all (Stoney/Lone Tree embayment). Treatment response at other locations was moderate.
The chemicals seem to be VERY effective at knocking back the first 90% of the milfoil growth. Chemicals are then SOMEWHAT effective at knocking back another 5-6% of what milfoil is left. But then the chemicals seem to be almost INEFFECTIVE at killing the last remaining plants.
Our team plans to try some new tactics this year in hopes of eradicating these hardy survivors.
For those interested in the details of our EWM sites on Torch Lake, please see the report below, while referring to the attached map.
1) Sand Sucker Holes – Our team found a small colony of EWM growing here last summer. After treatment last fall, it seems to be gone. Yay! We will continue to monitor this location every year though, as it has ideal conditions for re-infestation.
2) Alden Harbor – the harbor here has had, for many years, the largest patch of EWM by far on Torch Lake. It has been treated on-and-off with chemicals for much of that time. We suspect that the milfoil here has evolved a degree of resistance to the previous treatments. Last year, on advice of experts from EGLE, a new chemical called ProcellaCOR was used. Amazingly, during last month’s site visit, our team found almost ZERO milfoil! We were thrilled.
Not quite willing to believe it though, we plan to revisit the harbor with snorkel and SCUBA gear later this month to confirm our findings.
3) Old Boiler – a small, isolated few EWM plants are growing at this location. We plan to try hand-pulling it later this month. (Please note that hand-pulling EWM is a painstaking process, and not nearly as easy as it sounds.)
3.5) Lake Street boatwell – this is an old (early 1900’s?) private boat harbor near Alden. Our team just “discovered” EWM growing here last month, after the concerned homeowner contacted us. We will be treating this location with ProcellaCOR later this year.
4) Stoney/Lone Tree embayment – after treatment in previous years, this EWM colony is 95% reduced in size from its peak growth. However, it has resisted all efforts to kill the remaining 5%. The ProcellaCOR treatment last year had no apparent effect. We suspect this was not due to the chemical itself, but instead due to the open-water location. (Think wind and currents, dissipating the treatment before it could be ingested by the plants.) We are in conversation with our contractor about utilizing a more targeted method of treatment.
5) Ball Point – this was a newly-discovered EWM location last year. Unfortunately, due to a late start, we were unable to receive permission from adjacent landowners in time to receive an EGLE permit for treatment here last fall. We plan on treating it for the first time this year.
6) Butch’s Marina – was also not treated last year, despite having plenty of EWM growing in and around the boat slips. The problem in this case was the warm weather last fall, which meant that the boat owners did not remove their boats until extremely late in the season. By the time the boats were out, EGLE would no longer issue us a treatment permit, out of concern for a species of fish that spawns in the river at that time. (I forget the exact species.) In any case, this year our contractor plans to employ a backpack tank and use an underwater wand to deliver the treatment around the boat slips, earlier in the season, even if the boats are still in place.
7) Clam River Boatwell – is another early-1900’s private boat harbor. It was loaded with EWM last fall. We treated it with ProcellaCOR, but have so far this year been unable to contact the landowner in order to do a follow-up check. They have been very cooperative in the past and I’m confident that we will be talking with them soon.
Three gold stars if you made it this far!
Thanks,
Bob Milliron
