Aquatic Weed Control – Milfoil Weevil as a Control Method to Invasive Milfoil

Milfoil weevils  may be more helpful to local habitats and people than anyone recognizes. This stems  from the fact that it only eats milfoil and is harmless to humans).

Two types of milfoil exist in the United States. Eurasian Milfoil is invasive and non-native and the other  is simple native. The indigenous species places no threat but the Eurasian strain is very damaging. The  milfoil weevil now enjoys great popularity thanks to its love for the Eurasian Milfoil.

Eurasian milfoil (the only one that will be referred to in the rest  of the article unless otherwise stated) in all likelihood found its way into North America  somewhere between 1800’s and the 1940’s as it clung to Ships or was tossed out as  packaging material. Because milfoil can attach to any part of the bottom  of a ship and propagates quick, it can cause vast and undesirable shifts in the environment  and create problems for humanity.   Luckily this can spread the milfoil weevil as well.

This water plant grows  quickly, devastating local floras and limiting the food and living area for many marine  creatures.   Milfoil mats reduce the oxygen in the water, which  can threaten fish and cause unhealthy algae growth.

For  humanity, milfoil growth means a loss of boating, bathing, fishing and waterskiing areas.   For communities, the dense mats can clog water intakes or overflows, causing water shortages in some places and flooding in others.   Milfoil mats can even cause dam generators to choke or break  resulting in lower power production.

The milfoil weevil may  well be the answer to this plant epidemic.  The fact that it is indigenous prefers Eurasian milfoil over indigenous  milfoil, and kills the colonies step by step, giving native species time to recover, make  this the ideal. With a high breeding  rate and a taste for milfoil, the milfoil weevil and a smart and safe way to remove the  undesirable milfoil. When looking at how the milfoil propagates it becomes clear and why milfoil weevils control it so well.

It spreads when small pieces break off and sink to the bottom, there they take root. Using large marine reapers are not  the solution as the break up the milfoil too much and it grows right back. Vacuum dredging works a small better because no broken bits are left behind, but at  the same time the vacuum disrupts the water and could leave no flora life at the bottom.

  With a taste for Eurasia milfoil rather than the native milfoil, the weevil eats the plant  from the inside out, finally destroying the whole flora. Weevils  have a short life, living no more than thirty days, so before the winter comes, three  generations will live and die before they come ashore for the winter. Milfoil weevils  do have wings, but no one has ever seen them fly so no on knows exactly how the come ashore for the winter.  Regardless, once there they survive even the harshest Minnesota  winters.