Treatment work concluded for 2018

Aquatechnex has completed contracted treatment efforts for ISDA’s program for 2018.  We will resume at their direction in the spring of 2019.  


Eurasian Milfoil Treatment Scheduled for Tomorrow Cancelled.

The treatment for Eurasian Watermilfoil (EWM) that was scheduled for tomorrow, Thursday August 16th has been cancelled.  Pre Treatment evaluation of the sites today found that the treatment that occurred July 25th had results making this treatment unnecessary as no viable EWM was present.

This means that there will be no water use restrictions for drinking, irrigation or swimming as no herbicide will be applied.

As many of you were notified about this treatment and impending restrictions, we are also going to post signage on your docks indicating that the treatment has been cancelled, this will happen this afternoon.

If you have any questions, please contact ISDA Noxious Weed Program at 208-332-8667.

Next Treatment Scheduled

The next treatment on Hayden Lake will be performed the week of August 13th with the probable day of Thursday August 16 weather permitting.  The treatment of the north end of the lake had to be split into two applications to insure good dissolved oxygen levels and comply with the herbicide label.

This treatment will be applied to the area in the center of this zone, the shoreline areas were treated last week.  The map can be viewed at Treatment Map

The green areas on this map were treated last week and water use restrictions have expired.  The Red area on this map is the area subject to this application.

Hayden Treatments Completed for the Week, note change in water use restrictions

The shoreline “search and control” mission for Eurasian Milfoil was completed on Wednesday of this past week.  Initially the entire shoreline was mapped as potential treatment area, direction from the State was to target infestations along the shoreline out to 20 feet that were “topped out”.  As posting started for this work on Tuesday, the team noted large areas were devoid of Eurasian Milfoil.  The treatment was modified to a “spot treatment” in most areas and that changes the water use restrictions from three days to one day within those treatment zones, and no water use restrictions outside of the treatment areas.

The major treatment in the north end of the lake near Sportsman’s was completed on Thursday.  This 270 acre treatment plot had to be broken into two application to comply with the label, “when treated large areas split the application into two treatments at 14 day intervals to insure adequate dissolved oxygen levels”.  As such, this treatment focused on the shorelines of the lake to well off shore.  The second half of this treatment will be performed the week of August 6th, with a target date of Thursday that week.  This treatment will be well off shore and away from any water intakes, there will be no water use restrictions imposed on shoreline residents from this treatment and no need to post the shoreline.

Hayden Lake Second Treatment

The second treatment of Eurasian Milfoil on Hayden Lake will be performed this coming week, July 23-27.  The treatment map can be viewed at this link, Treatment Map Week of July 23rd

You will note two treatment objectives.

The first treatment performed will be scheduled for Wednesday July 25th with signs posted 24 hours prior to application on your shoreline.  This treatment area is a “seek and destroy” type of treatment in an area 20 feet from the shoreline to the shore.  Only visible “topped out” milfoil will be treated within the shoreline area (yellow band on the map) by water craft equipped with hand held spray systems.

The second treatment will be in the north arm of the lake near Sportsman’s Boat Launch will be a two part treatment with the first treatment occurring on Thursday July 26th and Friday July 27th if necessary.  We will be treating the shoreline areas within this polygon this week.  This application will be made with boats equipped with hand gun systems for areas around docks and boats and submerged injection drop hoses for those areas further off shore.

The water use restrictions from the treatment areas are: do not use water from the treatment area for potable water use or irrigation for 3 days post treatment.  There are no swimming restrictions, but we recommend staying out of the water for 12 hours to let the herbicide distribute.

We will be leaving the middle part of the lake in North Arm/Sportsman’s Bay zone until 14 days later.  This is to be compliant with Littora Herbicide Label (EPA registration number 67690-53) and the aquatic application requirements.  This second application will not impose water use restrictions on any of the shoreline areas.  

First Hayden Lake Treatment Completed, Second Round On Deck Week of July 23rd

Aquatechnex has completed the first treatment under the Idaho Department of Agriculture’s Eurasian Milfoil Control Program on Hayden Lake.  This treatment focused on bays and shorelines on the East shoreline.

A second round of treatments are planned for the week of July 23rd,  this treatment will focus on the near shore areas around the perimeter of the lake.  Maps will be posted prior to treatment.

First Hayden Lake Treatments set for Monday/Tuesday next week


Aquatechnex will be starting aquatic herbicide treatments targeting Eurasian Milfoil on Hayden Lake this coming week (July 9-10).  These treatments will be made at the three sites on this map First Hayden Treatment Map.

The Monkins Bay Site will be treated on Monday July 9th and signs will be posted today on all affected properties.  The other two sites north and south of Monkins will be posted on Monday the 9th and treated on Tuesday the 10th.

The product to be used is Littora Aquatic Herbicide.  There is a three day restriction on the use of treated water for drinking and irrigation from the treatment sites.  While there is no swimming restriction on the US EPA label, we recommend staying out of the water for 12 hours as a precaution to allow the concentrate to dilute and be absorbed by the target vegetation.

Any questions can be addressed to ISDA at 208-332-8667 or you can leave a comment here.

Please note that there will be a second round of treatments the week of July 23rd and public notice is going out this week regarding that.  Updates will be posted on that treatment after this is completed.