I hit the trails again on March 3, 2020 and counted 4 fall cankerworm females on 27 trees. Of course, dozens of other arthropods were trapped. Check out this study at Davidson College that shows this iNat project is reinventing the wheel: https://www.jncas.org/doi/abs/10.7572/JNCAS-D-1500002.1

Here's the abstract from their publication (copied without permission, I hope this is OK)

We monitored the accumulation of non-target arthropods and leaf litter on tree bands used for cankerworm control during a 4-week period in the autumn of 2013 prior to the beginning of cankerworm emergence. Accumulation of non-target arthropods and leaf debris may reduce the efficacy of tree bands in controlling cankerworms and harm non-target tree-dwelling arthropods. Ten oak trees were randomly selected from a set of 17 banded trees along one walkway on Davidson College in the Town of Davidson, NC, where cankerworms have recently become more abundant. Banding is known to capture high numbers of certain forest pests such as fall cankerworms (Alsophila pometaria (Harris)), although conclusive evidence that banding reduces defoliation is lacking. We found that non-target arthropods and leaves accumulated at a steady rate prior to emergence of cankerworm adults. Many predatory arthropods, including spiders, assassin bugs, praying mantids, lacewing larvae, and ladybird beetles were observed entangled and walking free on bands outside the Tanglefoot-covered area. We found indirect evidence for predation or consumption of trapped arthropods off of bands by birds and predatory insects. Early installation of tree bands prior to cankerworm adult emergence potentially damages the rest of the arthropod community.

I dissected this female Fall Cankerworm today (Alsophila pometari) and lo and behold she was packed with eggs, right up to her head, see: https://www.inaturalist.org/observations/40243107 As I wrote on this post, I had been intrigued earlier by the huge number of large eggs a female can lay, see: https://www.inaturalist.org/observations/38406580 Looks like a female at this stage is an egg case that has retained the ability to climb and release eggs when she gets to foliage, nothing else!

You can see why an army of females might prompt the use of tree bands. On that note, for this year, this seems not to be a concern. Since my last journal post I've surveyed 62 trees and have only seen this one female and one male Fall Cankerwrom.

Ken

I'm celebrating our 100th tree band species today. Maybe that shouldn't be a celebration, now that I think of it. For the record, this included North Carolina firsts for 16 species (7 beetles, 1 syrphid, 1 sawfly, 2 spiders, 1 psyllid, 1 moth, 1 ichneumonid, 1 collembolan, and 1 leafhopper). The collembolan, Prorastriopes wexfordensis, was a world iNat 1st (and 1st record for BugGuide) as was the zopherid beetle a world iNat 1st (Hyporhagus punctulatus). Needless to say, if you put Tanglefoot traps over a couple hundred trees or so you're going to trap (and unfortunately kill) a lot of bugs.

Sometimes I sample haphazardly, sometimes I make a count. Adding up days when I counted the trees I looked at during an outing this season, I've seen just 8 Fall Cankerworms on 102 banded trees.

-Ken