Ready action vs hasted wizard

[(Psi)SeveredHead]

So the opposing wizard is Hasted, and my sorcerer wants to ready a Fireball when the wizard casts a spell.

Can I disrupt both of the wizard's spells that round? Or just one?

 

[Crothian]

Just one

 

[Pax]

One per readied action.

However, ifyou use a spell with continuing damage -- say, Melf's Acid Arrow -- you can force a concentration check on subsequent spells, too (see the rules for such in the PHB, in the Concentration skill listing IIRC).