Monday, September 19, 2011

Wee Bugs

What's eating the Mile-A-Minute?
Yesterday afternoon Ann and I got out and walked a bit. She's been working on this project with the State to assess our ability to control the spread of an invasive vine referred to as Mile-a-Minute (Persicaria perfoliata). As indicated by it's name, the stuff grows quickly and being a native to Asia nothing here eats it. It just grows like crazy unfettered by pretty much anything.

The stuff is evil. The stems and leaves are covered with vicious little thorns that tear at your skin and lodge themselves in annoying places. The growth covers the ground, climbs bushes, trees and anything else it can find and kills the plants it covers. It self pollinates and produces a prodigious amount of berries that birds love. They then do us the great favor of crapping seeds hither and yon. This invasive likely escaped from plants that were imported from Asia. Good fun.

One of the reasons that this topic is important to trout anglers, especially small stream anglers, is that one component of stream health is good cover and stable banks. Many native species of shrubs and trees provide shelter from summer suns as well as root systems that keep banks from eroding. Without cover water warms. Without good root systems, banks wash away and silt in spawning grounds. Mile-A-Minute kills off those native species and replaces them with a ground crawling vine that has no valuable root system.

Oh, and those berries float really well, for up to seven days according to some research so when this stuff settles in on a stream it's easily transported downstream.

Why wee weevils of course!
(About the size of a pinhead. That
flawless skin is the palm of my hand)
One of the ways the State is looking to control the vine is by setting free these small weevils from Asia that only eat this stuff. Prior to release there was plenty of research to see if they ate anything else. Apparently they don't. That doesn't preclude the weevils from eradicating human kind as we know it but it certainly reduces the possibility.

We looked for evidence the weevils were still alive and munching at four sites. Three were by streams and one was in a  field. The weevils in the field seemed to be happiest. They were eating the heck out of the vine. Near the streams we saw less evidence of weevil damage and didn't see many weevils at all. That could have been due to the flooding we've had recently but there are likely other factors at play.

Be aware of what you're planting in your garden. In all likelihood it'll someday get loose into the wild. Plant more of the species that exist where you live and less of the exotic things. The fish count on familiar places to live. Leave the Asian stuff in Asia.