This does not look like a pest residue we are familiar with, at least not on blueberry plants. It's probably an insect cocoon or spider egg case, but can be left alone. It could also be whatever was left behind after a foraging bird plucked the rest of the object off, since they will glean insect eggs, cocoons, etc. from shrubs and trees. You can monitor the plants for signs of damage indicating a pest later in the growing season, but few insects cause serious damage to blueberries (and spiders are beneficial predators).

Miri