It invades and replaces native plant species. It can also reduce the quantities of desirable duck food species. It reduces the aesthetic appeal of Okanagan beaches due to the accumulation of plant debris and decaying vegetation. It obstructs such water activities as swimming, boating, water skiing and fishing. All of these activities Okanagan summer visitors come to enjoy, hence, it reduces the economic benefits of tourism.
Eurasian milfoil obstructs flood control methods, water conservation, drainage and irrigation works.
These are important regulators for managing the limited supply of freshwater in the Okanagan Valley. Dense stands of Eurasian milfoil may create habitats favourable for the production of blood sucking insects. The weed can alter temperature profiles in a lake by as much as 10 degrees Celsius per month in shallow water. The Ministry of Environment suggests that the spread of Eurasian milfoil has been stopped through public education methods. Education includes brochure distribution, signs at boat launches, poster displays and through the distribution of boater warning cards to resorts and at border crossings.