A couple of things I’ve noticed on the willow tree just off my balcony are of interest.
First, just today I noticed what I’m guessing is evidence of some bug/microbe activity; can anyone identify this white, foamy stuff that has recently appeared?
White Foamy Stuff
And while I’ve got the attention of those with some knowledge of willows and their doings, can you tell me anything about these rows of linearly aligned holes that now grace the willow’s trunk?
Holes
I don’t know what the foam is, but the holes look like the kind made by sapsuckers, whatever your local species might be. Compare your holes to the first picture on the left side of that Wikipedia page.
Try googling frothy flux. If that’s what it is, you can control it somewhat, but judging from the woodpecker holes in the underside of the branch, there’s more going on there than you can see.
If it would hurt anything if the branch suddenly broke off you may want to consider proactive treatment with a chainsaw.
The holes are woodpecker holes. I’ve seen froth on willows at the sight of injuries during hot weather. When the froth is on the slender branches by the leaves, there are often aphids under it. Wash off the froth and see what is under it. Seal it and or kill the insects under it by rubbing with your hands and or a stiff brush. The small woodpecker holes can be sealed if you feel the damage is great enough to warrant the effort.
Someone on this very message board once had a foamy substance much like that on their long grass. It was identified as the work of the spittlebug. The foam contains “nymphs”, the young form of the little creepy-crawlie.
Yep, woodpecker holes. They can be an indirect indicator of bores. It’s the birds trying to get to an insect food source.
In your first pic, it’s not a webbing is it? We had a web spread over limbs of my oak but an arborist informed me the insects creating it were actually beneficial to the tree as they ate and rendered harmless an otherwise parasitic fungus (or some such flora).
That’s what I thought when I read the OP, but not when I saw the picture. Here in Ireland the frothy material that protects the eggs of the froghopper is called “cuckoo-spit”. There’s a lot of it around at this time of year. But it looks nothing like that picture, and wouldn’t be found on the bare bark of a tree.