Pear tree black knot?

I didn’t think pears were susceptible to black knot. Is this growth on a branch from a Moonglow pear the early stages of black knot? The pear tree also was hit with blotchy yellow leaves that some turned black. I removed most of those leaves from the tree and the branch so I could get a clear picture.

I haven’t had a black knot infestation for a few years since I took out my black knot magnet the Methley plum. I saw this swelling on several plum trees this summer and promptly removed them as I suspected it was the beginning of a black knot infestation. Am I correct in assuming this is the beginning stage of black knot?

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The photo is a little out of focus.
But that looks like an eastern tent caterpillar egg mass to me.
Or something similar.
Not sure if you have those out there.
Maybe you have the western tent caterpillar ?


I haven’t seen an outbreak of tent caterpillars on my trees in a very long time. However, the neighbours trees on both sides of me got hit pretty hard with caterpillar nests. I could see them on their trees, but mine were all luckily clean.

Perhaps you are right and that is what it is. I’m glad I didn’t sever the scaffolds that I found those things attached to on my plum trees. I just carved them out hoping that was enough to stop the spread (thinking it was early stage black knot).

Thank you, I hope that’s all it is. Good thing I didn’t do a hatchet job on my trees out of paranoia.

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He is definitely right, that is a tent caterpillar egg mass. Good you removed it.


I often collect those egg masses and throw them into a Multiflora rose bush( the invasive ones) around the farm. The hatching caterpillars have no choice but to eat the first thing they come across. So they defoliate the multiflora rose, not the fruit trees.
Makes it more worth while to hunt for them .


Nice! :grin: :+1: