Monday, October 19, 2009

Milfoil Weevil as a Control Method to Invasive Milfoil

By Dave Duncan

The Milfoil weevil is a small water bug that may be able to rescue troubled ecosystems. This stems from the fact that it only eats milfoil and is harmless to mankind).

There are two types of milfoil to be found in the United States. One is native and the other invasive (Eurasian Milfoil). indigenous milfoil is merely irritating, but the invasive species is a threat to all bodies of water in the northern US states. It is this one that is making the milfoil weevil so significant.

Eurasian milfoil (from this point forward all milfoil will be considered Eurasian milfoil unless otherwise noted) was most probably introduced to the Us sometime between the late 1800's to 1940's as either a stowaway on a Boats ballast or tossed shipping material. Milfoil can easily travel on the underside of a ship and grow rapidly, which causes damaging ecological changes and causes problems for people. This is also a great way to spread the milfoil weevil as well.

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

The milfoil is more irritating for people than harmful because it can lower the amount of water available for boating, fishing, swimming and waterskiing. In communities, the dense mats could cause floods and droughts because of closed intake or overflow pipes. Milfoil mats can even cause dam generators to foul or break resulting in lower electricity production.

One little weevil could hold the solution to the milfoil dilemma. Eurasia milfoil is a favorite of the milfoil weevil rather than the indigenous kind; this results in the invasive species being step by step destroyed and indigenous floras slowly returning to their natural place. Coupled with a high breeding rate, the weevil is the safe and ideal answer to the milfoil problem. The weevils are a clear solution to the milfoil problem, especially considering the rate at which the flora spreads.

It spreads when small pieces break off and sink to the bottom, there they take root. Aquatic harvesting devices are not successful because they break the flora and pieces come off and replant themselves elsewhere. 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 floras.

The milfoil weevil will destroy the whole flora by digging into the stem and eating from the inside out, which will kill the flora. Weevils have a short life, living no more than 30 days, so before the winter comes, three generations will live and die before they come ashore for the winter. The weevils do have wings, but have never been seen flying, so whether they swim or fly ashore will remain a mystery. Regardless, once there they survive even the harshest Minnesota winters.

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