Aquatic Plant Management 2009

This page has a tendency to fill up during the course of the year & become quite cluttered.  We're starting 2009 with a clean slate.  Let's hope it stays simple.

Fall Survey -  October 10th we accompanied Doug Pullman, our lake limnologist, on the fall plant survey of Cedar Lake.  Doug's findings will find their way into his updated annual report which will come out late this winter.  This will be what we make decisions on, not the uneducated summary that follows here, but at a summary level, this will be a heads up on what Doug will officially report on.

North of the causeway Doug was surprised by a couple of situations with the variable milfoil that has plagued us.

 

First, this plant has spread notably since the spring survey.  Both Doug & Jeff (our treatment applicator) are concerned about this spread.

 

The 2nd situation is, there are significant patches of variable milfoil that are behaving as they are expected to this time of year, namely, they are laying down, dormant on the bottom of the lake.  They are not actively growing plants.

 

Then there are a significant portion of variable milfoil plants that are up, growing, some even still flowering on the surface.  While the two plants (those laying down dormant & those actively growing) look identical, they are behaving almost like 2 different plants.  Doug has not reached any conclusions about this, but he did allow that we might be seeing two different plants, the later, perhaps some sort of hybrid.  Anyway, seeing actively growing variable milfoil plants was a surprise  to him.

 

South of the causeway, south of St George's Pte, the eurasian we treated & took down last year is coming back & will require treatment again next year.  Doug believes that this plant, that has now spread south to the Briarwood Bay area, is really a eurasian milfoil hybrid & we'll treat it accordingly next year. 

 

The channel west of St George's Pte is infested with wild celery & will need to be hit hard next year.  Wild celery in general is notable at various locations around the lake, but especially south of the causeway.  Wild celery is hard to get rid of & is capable of spreading.  We'll need to watch this closely.

 

Starry Stonewort, noted in our lake near the causeway a couple of years ago seems to have disappeared.  Doug is reluctant to leap to that conclusion, because you rarely completely eliminate any plant, but he didn't see it this time out.

 

At the far northwest, the area from the Indian statue on the shore, south past the little stone house, that historically is one of the worst milfoil areas on the lake, is heavily infested with eurasian milfoil.  Doug sees this as a good thing.  Hoping that in the spring the eurasian will pretty much crowd out the pesky variable milfoil which has been such a problem there.  We can easily treat eurasian, so, maybe that area won't be so bad after treatment next year.

 

Otherwise, chara is pretty widespread, but is not a nuisance, so, this is not a problem.  We saw a good scattering of pond weed here & there, some even on the surface flowering, but absolutely no problem.

 

Overall, I THINK Doug is going to come to the conclusion that our plant diversity is down (not good).

 

Doug talked at some length about plants producing things called polyphenols which form a protective coating on the plant.  Coincidentally I had just read about polyphenols & redwoods.  In the case of the redwoods they keep insects from infesting the trees.  In the case of aquatic plants, they keep the plants safe from toxins in the water, including herbicides.

 

The last few years Doug & Jeff have been adding algaecides to the treatment mix to attack & breakdown the polyphenols, so that the herbicides can get in & do their job on the plant.  This is a complex issue.  Doug believes that plants produce polyphenols as needed.  If the water is highly toxic, then they produce more.  If it is low in toxicity, they produce less.  In cases where lakes have large wetlands adjacent to them, the lake water is going to have more plant toxicity.  Therefore plants in that environment will produce more protective polyphenols.  I don't need to point out that north of the causeway we have a wetland area on the entire western shoreline, with 2 creeks feeding water directly into the lake from that wetland.

 

By the way, we're not talking about a toxicity that affects human use of the lake, rather the toxicity we're talking about has a detrimental affect on plants only.

 

Anyway, this whole subject most likely plays a role in the effectiveness of treatments in the north.  Doug & Jeff will continue looking very closely at this matter & I'm sure will be adjusting the algaecide portion of the treatment to more effectively deal with the polyphenols, and therefore allowing the herbicides to be more effective in plant treatment.

 

So, on October 11th, that's it for aquatic plants in 2009.

2009 Treatment Assessment - All Eurasian Milfoil treated both north and south of the causeway is down & taken care of for the year.  This completely clears the mess in the bay south of St George's Pte, and eliminates anywhere from 10% - 60% of the problem in weed beds north of the causeway.

The remaining problem north of the causeway is green variable milfoil.  Where 2-4-D was used it was eliminated.  Where the liquid chemical cocktail was used, the treatment ranged from marginally effective, to a noticeable impact on plants, but they didn't go down, to no impact at all.  The liquid was unreliable & ineffective.

Unfortunately, the liquid is all that could be used near shore.  2-4-D cannot be used within 250 feet of shore.

On the eve of doing another 2-4-D treatment to get more of the plants farther than 250 feet from shore we observed a dramatic drop of plants, both close to shore & out.  Not all dropped but a significant portion did.  Consequently we decided to cancel plans for any further treatment on 2009.

Spring Survey

June 6th Dr. Pullman our lake manager limnologist, Gary Crawford, our fish biologist and Russ Anton spent the better part of the day conducting the spring plant survey for 2009.  We're pretty much picking up where we left off from last year.  Green variable milfoil continues to spread throughout the lake north of the causeway.  Last fall we noticed Eurasian milfoil mixed in with the green variable pretty much throughout the north.  Eurasian is an invasive plant, and therefore we will be aggressively treating most major stands of milfoil north of the causeway this year.

South of the causeway, in the bay south of St George's Pte & in the canal west of it, Eurasian milfoil is a problem.

June 6th was to early in the season to determine any but milfoil problems.  The cold spring has retarded all other plant development.

June 11th Treatment

Aquatic Services applied herbicides to selected areas of the lake today to treat milfoil.  The three following links are for three maps of sections of the lake depicting treatment areas.  The skull & crossbones waypoint markers on the maps delimit the treatment areas.  

LakeInformation/AICLA - 2009 June 11 North Treatment - 1.pdf

LakeInformation/AICLA - 2009 June 11 North Treatment - 2.pdf

LakeInformation/AICLA - 2009 June 11 South Treatment.pdf

We should see results from the treatment by June 25th.

As always, if you are in the treatment area a sign will be posted on your property.  If you have no sign, then there was no treatment near you & there is no restriction in your area, but if you use the lake within 24 hours from June 11th, please be aware that you may very likely venture into areas that were treated.  Things like water skiing, tubing, swimming, or even fishing in areas that you don't inspect for shoreline signs is strongly discouraged.  All areas treated in the lake will be safe for swimming and fishing 24 hours after the application.  Any water use questions, call Russ Anton (989)739-5027.

Again, this will be exclusively a milfoil treatment. 

A 30-50 acre area of milfoil in the M01N to M01S treatment area (map #2 above, 2009 June 11 North Treatment - 2) went untreated because we ran out of chemicals.  A plan will be developed for that treatment later in the season.  Check back here for further details as things unfold.

*Spirogyra Algae  (picture, Spirogyra.jpg )

Spirogyra algae (as opposed to the jazz group) is an early blooming filamentous green algae.  We've had it in our little cove at the very southern end of the lake for the last two years in the early spring.  Algae blooms are always indicative of the presence of nutrients (phosphorus) in the water.  As the weather and the water warms, spirogyra goes away.  In our case, by the time we're even thinking about getting in the water, spirogyra is long gone.  So, for now, its just unsightly and something we'll just watch.  Although, it has been more prevalent down here this year then last. If you've seen it along your shoreline, please drop us an E-mail or give us a call.  Because it is such an early season issue, and goes away when things warm up, we aren't out on the lake yet with any sort of regularity and don't have an idea of how widespread it is on the lake.

Last year the association purchased equipment to do our own total phosphorus monitoring around the lake.  We'll certainly be testing in areas that seem to have indications of high nutrient loads in 2007.