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

The Milfoil  weevil is a little] water bug that may be able to rescue suffering ecosystems. This weevil may prove it usefulness in eating milfoil and restoring the  health of an ecosystem while causing no harm to humanity.

There are two types of milfoil to be found in the Us. There is a  indigenous one and an invasive species of Eurasian milfoil. The indigenous species poses no threat but the Eurasian strain is very damaging. Eurasian Milfoil is the reason the milfoil weevil is so important.

Eurasian Milfoil (the primary milfoil that will be referenced from  this point on) probably came to The Us between the 1800’s and the 19404’s as an unwelcome  passenger on some large ship. Milfoil can easily travel on the bottom of a boat and  grow quickly, which causes damaging ecological changes and causes problems for humans.   Luckily this can spread the milfoil weevil as well.

  Milfoil spreads rapidly, which results in less growth for indigenous plants, less food for  some creatures and less living habitat for small] marine creatures.   Milfoil mats decrease the oxygen in the water, which  can endanger fish and cause unhealthy algae growth.

For people, it cuts the recreational uses of the water by swimmers, boatmen, and  fisherman.   In  residential areas, the dense mats could cause floods and droughts because of clogged intake or  overflow pipes.   The mats can be especially detrimental to dams by breaking or choking generators and  reducing electricity output.

The milfoil weevil may  well be the answer to this plant epidemic.  The fact that it is native favors Eurasian milfoil over indigenous  milfoil, and kills the colonies gradually, giving indigenous 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  unwanted milfoil.   The weevils are a clear solution to the milfoil problem, especially considering the rate  at which the plant spreads.

This water flora spread quickly because broken pieces can sink to the bottom and easily form new floras. Using large marine harvesters are not  the solution as the break up the milfoil too much and it grows right back. Vacuum dredging is only slightly more productive in that it catches small broken pieces,  but it also causes a great disturbance in the water and can strip the bottom of all plants. 

The milfoil weevil though prefers Eurasian to indigenous milfoil so it eats that first,  slowly weeding it out by tunneling into the stems and eating it from the inside out. With only 30 days  to live, the milfoil weevils will go through three generations before coming ashore for  the winter. Although they have wings they have rarely been know to fly so no one know if milfoil weevils fly to shore or swim.   Once established in a habitat, the milfoil weevil will live even through the coldest Minnesota winters.