The shaded areas show where herbicides have been and will be applied on Chautauqua Lake.

Herbicide treatment for eurasian milfoil on Chautauqua Lake is scheduled to take place Monday and Tuesday. .

The state DEC has permitted 369 acres of ProcellaCOR EC in the waters near Ellery, Ellicott, Busti, Bemus Point, Celoron and Lakewood. Aquathol K treatment for curly-leaf pondweed on 115 acres of Ellery, Bemus Point and Celoron was performed May 24, according to the Chautauqua Lake And Watershed Management Alliance. Solitude Lake Management will perform the treatment. The DEC approved about one-third of the requested acreage for curly leaf pondweed for the May herbicide application.

“We have some good news to report,” the Chautauqua Lake Partnership said in a Facebook post earlier this week. “The (state) DEC approved all 370 acres requested for herbicide application for Eurasian milfoil. That’s great. We are in preparation for the application process. The communications many of you sent to the DEC in the last week or so were critical to this approval — thank you! We only received permit approval for 105 acres out of 340 acres requested for the curly leaf pondweed, so the approval for the Eurasian milfoil is huge — especially in view of the condition of the lake.”

May treatment areas totaled less than 3% of the lake, according to a notification letter from the towns and villages. Treatments Monday and Tuesday will comprise 4% of the lake and include 138 acres in the Lakewood/Busti area and 115 acres in the town of Ellicott.

There is no restriction on swimming, use of water for drinking nor fishing in the areas where herbicides will be used next week. There are limitations on livestock watering and irrigation until herbicide concentrations dissipate.

Signs will be posted at public access sites around the lake and along downstream waters notifying users of any water use restrictions. When all restrictions are lifted, the signs will be removed. Information on restrictions can also be found on the Ellery, Busti, Bemus Point, Lakewood, Celoron or North Harmony websites or by contacting the respective town or village clerk.

Next week’s herbicide treatments will be deployed in between 4 and 6 feet of water. Treated areas must be bouyed before treatment. Undeveloped shorelines cannot be treated, according to the DEC permits.

In a recent news release, Chautauqua Watershed Conservancy continued to express concerns about the use of herbicides, including the May treatment.

“CWC believes that, under certain circumstances and with limited, targeted use, herbicides can be an appropriate tool for the control of invasive, non-native aquatic plants, especially for eradicating new infestations where other means (such as mechanical or hand harvesting) are not feasible,” officials said in the release. “CWC has specific concerns about the recent in-lake treatments, however, in that the herbicides chosen are not plant specific and will target and kill both non-native and beneficial native plants which are critical to our local fisheries. … CWC asked that the use of herbicides be strictly targeted and limited in application to certain areas where dense milfoil growth is documented and likely to interfere with high levels of lake use.”