BY advanced level of technology, I assume you mean where we are currently. Tech is really not your only stumbling block here. The real one is this: a global economy.
The EU is currently the largest global importer and exporter of agricultural products.
So there really isn't a way to isolate this, to make the EU suffer exclusively if there's a famine. Nope. It's not likely to kill people so much because they can just import more from other places, but it IS likely to screw the world economy in a big, big way.
However, if you do want to kill people in Europe and you don't care about your mortality rate in other countries, certainly, you should make it a global pandemic.
The other option is to have it be discovered as a thing--like an eco terrorist does it and lets the world know after it's begun spreading in Europe, but before it gets out to other countries. If it's bad enough and it's caught just wrong before it goes elsewhere (or it does go elsewhere, completely devastates a region) and they totally quarantine Europe.
The economy is going to take a hit before people start dying directly from starvation. And they'll die because they can't afford food. For 1%-5% to die, raise food prices as a result of this--not all of them will die because they have starved. Some will die because they are unable to afford their rent, because food prices have skyrocketed.
You want to do this with a minimum of Anarchy, so, all along, the government can be providing assistance, if you qualify and things are orderly.
However, if you really think that people are going to go hungry without some kind of riot and anarchy on some level, then you forget most of human history.