Albert Barnes Commentary Exodus 10:17

"Now therefore forgive, I pray thee, my sin only this once, and entreat Jehovah your God, that he may take away from me this death only." — Exodus 10:17 (ASV)

This death only - Pliny calls locusts a pestilence brought on by divine wrath. Pharaoh now recognizes the justice of his servants’ apprehensions (Exodus 10:7).