It doesn't sound encouraging ....

http://www.ecy.wa.gov/programs/wq/pl...s/milfoil.html

Eisboch

That information from Washington is similar to here in New Hampshire. There
is basic disagreement about what to do, and who should pay for the program.
Our Fish & Game department is reluctant to approve wide-spread use of
herbicides (2,4,D), and the other methods suggested by Washington are very
expensive and don't work all that well.
Economic damage, in the form of reduced property tax revenues, may prove to
be the incentive needed to get local and state governments to take action
against milfoil. Just recently I heard of a waterfront property owner on our
largest lake who got a 25% reduction in his land assessment because of
milfoil in the water. That will be a significant loss in tax revenue for his
town. New Hampshire towns do love to tax waterfront properties; the owners
are typically "out-of-staters" who can't vote in the town, and, at best, are
simply tolerated by the locals. The loss of this cash cow may encourage
towns to get interested in milfoil.

I would be interested to hear about a state that is using 2,4,D in a major
program.