ויסר מעלי רק את המות הזה (בא י:יז)

Why did Pharoh refer to מכות ארבה (the plague of locust) with the term “מות” – death, ” not by the other plagues? The Gemara (נדרים סד) says: “Four things are considered as if one is dead, a poor person, a Metzorah- an inflicted person, a blind person, and someone who doesn’t have children.”  During the plague of Arba “ויכס את עין כל הארץ ותחשך הארץ” – the locust covered the earth and became dark. “ The Egyptians sat in the dark like blind people. Therefore, Pharoh said ויסר מעלי רק את המות הזה.