Squash Lake Survey Results and Recommendations from Onterra, LLC

Hello Stephanie,

On September 1, 2009, Brenton Butterfield and Todd Hanke from Onterra, LLC visited Squash Lake, Oneida County in order to survey the lake for Eurasian water milfoil (EWM). The survey began with a meeting between the Onterra field crew and the Squash Lake Association (SLA) President, Mr. Pat Dugan, at the lake’s boat landing. Using the Onterra boat, Mr. Dugan showed the field crew where the known locations of EWM were within Squash Lake. Following the short tour, our crew returned Mr. Dugan to the boat landing and proceeded to survey Squash Lakes littoral zone (lake are supporting plant growth) for EWM. Survey conditions were very good with clear water and good light.

Our crew located EWM in numerous locations with Squash Lake (see attached map). The heaviest concentrations were in the areas found by the SLA; however occurrences of single plants and clumps of plants were located in other areas of the lake. During the survey, no large, contiguous, dense areas were found, so the infestation is still considered light. In fact, the crew did not locate any EWM areas within the lake that were large enough to effectively map by using the boat to create a polygon with our GPS data collector. In other words, all EWM were so small, that the crew was only able to mark them using points. As indicated on the attached map, the points indicate areas where a single or few plants were located, a clump of plants (5 or more plants in a tight clump), or a small colony of plants (an area containing plants of less than 25-40 feet in diameter).

As mentioned above, our results indicate that Squash Lake has a light occurrence of EWM within it; still, there is enough EWM to warrant a herbicide treatment next spring (2010). The attached map indicates our recommendation to treat seven areas within Squash Lake totaling 7.2 acres. Please note that this does not mean that Squash Lake contains 7.2 acres of EWM, in fact, with the light occurrence found within the lake, it is impossible to put an acreage to the EWM population.

We recommend that the areas indicated be treated with granular 2, 4-D, sold under the trade name of Navigate. Most of the area should be treated at 150 lbs/acre while 3.1 acres should be treated at 200 lbs/acre. The latter dosage was selected for areas with steep slopes to prevent dilution of the chemical around the target plants (EWM). Both of these dosages are within the label-rates approved by the EPA. Kevin Gauthier can provide names of reputable applicators that work in your area and would be able to provide an estimated price. The attached map should be provided to the applicators and used within the treatment permit application. Further, your group can rely on the applicator to discuss the treatment and the use 2,4-D in your lake. Once you select an applicator, we can provide the treatment areas in an electronic format that can be used in their GPS.

Finally, if you have questions or require additional information, please feel free to contact me.

Thank you,

Tim Hoyman, CLM
Aquatic Ecologist
Onterra, LLC
135 South Broadway Suite C
De Pere, WI 54115
Voice: 920.338.8860
Fax: 920.338.8865
Email: thoyman@onterra-eco.com
Web: http://www.onterra-eco.com