Adam Clarke on Exodus 10:13

The Lord brought an east wind - As locusts abounded in those countries, and particularly in Ethiopia, and more especially at this time of the year, God had no need to create new swarms for this purpose; all that was requisite was to cause such a wind to blow as would bring those which already existed over the land of Egypt. The miracle in this business was the bringing the locusts at the appointed time, and causing the proper wind to blow for that purpose; and then taking them away after a similar manner.