|Male Winter moth fits inside circle the size of a nickel.
Females are just under a half-inch in length.
An insect invasion has plagued eastern
|Female, note small wings
11/14/14 update: After a few night frosts, moths are beginning to appear in Maynard.
11/26/14 update: My big birch tree has more than 500 males and females stuck in goo!
12/15/14 update: No new sightings, so removed plastic wrap.
|TreeTanglefoot on birch tree. Applied
on plastic wrap, not directly on tree.
See photo below for results.
|Moth menage a trois stuck in the goop. Males are attracted
to pheromones released by females.
Click on any photo to enlarge.
These two moth species are examples of slow expansion because females are unable to fly. Egg laying occurs on or near the tree they grew up on. Dispersion is achieved be a few methods. Post-hatch caterpillars can release a silk strand from the abdomen, then unclasp from the twig and allow wind to blow them to a new location.
This means of travel is better known for young spiders, and called 'ballooning.' Older caterpillars can descend to the ground and explore, one tiny footstep at a time. Either way, the failure rate is high, but enough succeed that territory continues to enlarge, and areas that are sprayed with pesticides will re-infest over time.
2015, and my birch trees' infestation was even worse. This year I got the goop on the tree by mid-November. Trapped so many that I had to remove it and reapply fresh wrap and goop on Thanksgiving, and then again December 1st. Will see come spring how much this slaughter benefited the trees. Biological control has proved successful in Canada - not clear if this method has yet been introduced to U.S. There are two insect species (a fly and a wasp) that specialize in winter moths. Their larvae consume the winter moth caterpillars from the inside.
2016: Less severe, and more males than females. That suggests I am getting my own local females and males, but additionally attracting males from the neighborhood. If this repeats in 2017, suggests that it is not necessary to wrap every tree, as wrapping only some trees will remove males from the mating equation. However, this is a strategy that works if males mate only once.