FRC Partners with USDA to Explore Solutions to Milfoil Problem

Milfoil Weevil
The milfoil weevil

Over the last year, the Fall River Conservancy has been exploring options for reducing the spread of Eurasian watermilfoil (EWM) throughout the Fall River.  One of these options, utilizing a biological control known as the milfoil weevil, presents a hopeful solution for combatting EWM.

FRC is proud to announce a new partnership with the USDA Agricultural Research Service (ARS). The purpose of this partnership is to assess the feasibility of successfully using weevils to control Eurasian watermilfoil (EWM). USDA is currently working with live weevils in their Albany laboratory where they are simulating the cold water conditions of the Fall River. By observing how weevils interact with EWM under these conditions, they will be able to better assess the potential effectiveness of a full scale bio-control program.

Although weevils are known to destroy EWM in lake systems throughout the Midwest, the cold, spring-fed water of the Fall River presents new challenges. New research conducted by USDA, shows that small variations in water temperature can play a critical role in the developmental life cycle of weevils. Weevils have what is called a “developmental base temperature” of 10° Celsius (50°F).  At this temperature, weevils become active, but they won’t lay eggs until water temperatures reach approximately 15° Celsius (59°F). In the upper Fall River near Island Road Bridge, summer temperatures average around 14° Celsius (57°F).

To address this issue, FRC and USDA will be looking for small off-channel ponds where we can successfully propagate self-sustaining populations.  USDA and FRC will continue working together to ensure that any future biological control program will lead to a successful outcome.

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