Several times this summer, I checked the pines for tip damage and found none. I may have sprayed insecticide once early summer 2010, not sure, but I know I haven't sprayed since. Prior to deployment of the 'zappers, I was spraying three or four times each year.
We have another tree, a Dawn Redwood, that is prone to bagworm infestations. It has also been worm free the last two summers despite the lack of spraying.
We have had unusual weather the last three years, less rainfall, hotter than normal summers, colder than normal winters. Perhaps the lack of moths can be blamed on the weather.
Kathy's convinced that the bug zappers are a success. She wants me to buy more so we'll have replacements ready. I think I'll wait a while.