Just as bacteria have evolved resistance to many of the antibiotics once used to kill them, modern bedbugs are almost invulnerable to at least some insecticides.
Along with his super-strength is his super-endurance, as Myers seems to never physically tire and is all but invulnerable to life-threatening injuries to include being shot in the head.
His healing factor works on an order of days, not seconds or minutes, so even though he is super-agile, super-strong, and can shoot super-strong webs, he's not completely invulnerable.
Moreover, he was a boy whom no man could hurt; an invulnerable and dodging serpent who, when chased into a corner, flew out again between his captor's legs, scornfully yelping.