If you are at the point where your opponent is spamming scorpions, then there's lots of metal to play with.
In that case cerberus with overlapping fields of fire will certainly do grievous damage to any scorpion in range that they find. Scorpion is not that great when it is detected and slow to get out of range of the very long ranged creberus. Not only can cerberus deal with scorpion, but it can also dominate a wide area around itself.
Likewise, a good air player can wreck scorpion infiltrators. Likho spam is aggravating to deal with and a bombing run by a flock of them can turn almost any target to debris.
The key to this is detection of scorpion.
The solution is Flea.
Flea spam that saturates an area with a blanket of cover not only detects scorpion but also a variety of other cloaked pests. Fleas provide vision for your own long range artillery and can, at a pinch, rush in and deal with low firing rate but high damage units like cyclops.
Build Flea.