problems with another diquat treatment in Mass.

CenterPondMilfoil-1.jpg
Posting for Treatment June 18, 2008
June 18, 2008. Center Pond, Becket, Massachusetts, USA.
This posting is for a 1.45 acre treatment with Reward (active ingredient diquat dibromide) by Aquatic
Control Technology, Inc. performed on June 18, 2008. The area of milfoil infestation was
approximately 1/4 acre in size. A larger treatment size of 1.45 acres was deemed necessary due to
the area being out near the middle of the lake and not having shelter from any bordering shorelines.
CenterPondMilfoil-2.jpg
Area Treated June 18, 2008
June 19, 2008 - This is the area that was treated. The buoy marker is to warn boaters of the Big Rock
there. This area harbored a dense bed of mature milfoil plants that had grown near to or up to the
surface. Some of these plants, those which had reached the surface, had flowered and produced
seeds.
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Hazard of Long Weighted Hoses
June 19, 2008 - The day after treatment. Long weighted hoses were used to insert the herbicide down
near the bottom. These hoses were placed inside the weedbed and broke milfoil stems near the
bottom. The long stems in the photo were held in place by the tops of the remaining plants. Others
escaped and floated all around the lake. We removed those in the photo and any we found floating.
Some, however, were found in various places in the lake and had rooted and started new plants.
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Regrowth after 5 1/2 weeks
July 25, 2008 - The defoliated stems of the milfoil plants are still in process of decay while new stems
have begun to grow from the roots. Treatment with diquat does not kill the plants - it decays the plant
material above the bottom of the lake. This adds decaying plant material and nutrients to the water and
decreases water clarity.
CenterPondMilfoil-5.jpg
Regrowth after 20 weeks
November 4, 2008 - Some defoliated stems are still in process of decay while the new growth has
returned to within 2 inches of surface. All plants in this photo are milfoil, including many young plants.
The weedbed after treatment has many more plants per square foot than it did before the treatment.
The treatment opened the area up to sunlight that was previously blocked by the mature plants,
allowing more plants to root than was possible before. Consequently, this area is now more difficult to
hand-pull.