Can Earth's Electromagnetic field block asteroids?

[alexhenderson]

If it can block portions of anti-matter I am assuming. Could it possibly be true, that it can deflect asteroids?

[G01]

The electromagnetic field around the Earth can deflect charged particles. However, in large bodies charges tend to cancel and the asteroid would carry little to no net electric charge. Therefore, the presence of the Earth's field will not alter it's trajectory.