I like to stop by my state's extension service on occasion to read the news. The news for the last couple of months have been all about alien invasions and how to control them. The first alien invader that we noticed showed up at our house in 2006 around Thanksgiving time. Their little triangular shapes swarmed out of the sky towards the house trying to break in. "Take me to your lights," they wanted to say. Yes they were moths - winter moths.
They coated any surface outside that was white. They beat themselves futilely against the glass at night. They totally covered our white doors, making it an effort to get inside without dragging a dozen with us each time. They were very annoying and we hadn't seen them before. They had probably been around the year before, but not in enough profusion to make us sit up and take notice. Now we do.
What weird moths they are too. They are most prevalent in December. Their biology must be very different to be able to function in the cold. I really wonder what their antifreeze is. Northern New England doesn't get them. It is too cold. We live right on the border of their range. We had some very frigid temperatures in November and December. I'm hoping it killed a lot of them off, because they have become a very big pest to our forests.
In springtime their children munch on the trees. I haven't seen such caterpillar poop rain since the last gypsy moth invasion. It comes in such quantities, I keep thinking of sweeping it off my patio and collecting it for fertilizer for the garden. On Cape Cod the invasion is so bad, the oak trees have started dying. They can only take so many years in a row of getting defoliated in the spring before they start to die (the invasion started in Plymouth in 2003 and has spread).
The one good thing that seems to have come out of it in my yard has been the influx of birds. I have seen more different species of birds in my garden than I ever have before (especially warblers). Those caterpillars make good baby food.
Luckily we have a good weapon against our invader. Our own little dive bombing aerial weapon is a fly. Though maybe it is more like ground troops setting mines. They lay their eggs on the leaves which the caterpillars eat. The parasitic fly grows from the soon to be ex-caterpillar. When Nova Scotia was invaded with the same moth, it took ten years for that control to work. Massachusetts started releasing flies in the area about four years ago, so we have a few more years of heavy infestation to go yet. I hope my trees survive.
Our other invasion is also taking down our trees, but deserves its own post.