Treatment Schedule

Both a liquid formulation (Sonar Genesis) and pellet formulation (Sonar H4C) of the herbicide fluridone are scheduled to be utilized in designated treatment areas within Lake Sebago. Six treatments are slated to occured between June and October 2024.

2024 Treatments will begin on Thursday June 6th. There will be a 24 hour swimming restriction in place for the northern basin (see hatched section of the map below) until the morning of June 7th.

Shoreline signage will be placed at public access points notifiying of all water use restrictions.

A single application of a granular formulation of chelated copper (Harpoon) occured in July 2023 to >1 acre of the lake. Product labels are linked below. Both target and non-target species were monitored for impacts throughout the season.

Product Labels

Product labels can be found here

Project Permits

Article 15 Aquatic Pesticide Permits:

Sonar Genesis
Permit # AV-3-24-170
Sonar H4C – Permit # AV-3-24-169
Harpoon – Permit # AV-3-24-171
SPDES : NYP260127 (Neg Dec)
SEQR Neg Dec posted in ENB 2/1/202

Water Use Restriction

An irrigiation restriction will be in place for the entire lake between June and October 2024. Treated water can not be used to irrigate greenhouse or nursery plants, turf grass, or plants in the nightshade family.

There are no restrictions for fishing, livestock watering, or drinking associated with this project.

There are no swimming restrictions in the Southern Basin associated with this project.

(See map for 24-hour swimming restrictions for Nothern Basin Only that will be scheduled up to 6 times during the season from June-October).

There are no restriction for boating.

Harriman Group Camps Information Meeting

A virtual meeting took place on May 7, 2024. This meeting included a presentation with background on the hydrilla infestation within Lake Sebago and provided details on the success of the 2023 treatment, and was followed by a Q&A session. A recording is available here.

A recording of the 2023 introductory meeting can be found here:
A recording of the meeting is available on YouTube and can be found at this link.

Lake Sebago Hydrilla Control Project