Yes! Go to one of the posts from the instance you want to silence, click on ... and then "block domain".
Bear in mind this will also remove any followers you have from that instance, but in the case of a bot instance this won't be a problem.
Alternatively, use filters to hide/block posts with particular words or phrases:
https://fedi.tips/filtering-your-timeline-to-hide-posts-on-mastodon/
Just use the hashtag without the # as your filter to hide posts with that tag.