I have a blackberry with strange modules that look like tiny snails they have pus inside but don’t have crunchy shells and there

Question

are hundreds of them on the main stem and ideas please I can send a picture if it would help

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Answer 1

They appear to be a type of slug, which is, essentially, a snail without a shell.

This article will help you: https://www.gardeningknowhow.com/plant-problems/pests/insects/kill-garden-slugs.htm

Answer 2

This is a Scale pest. Isolate the plant from other plants.

Treat with Neem Oil.
https://www.gardeningknowhow.com/plant-problems/pests/insects/control-plant-scale.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm