What is causing high food prices?

1 year ago, there was no food price crisis?

Suddenly now prices of essential food from rice to corn has gone
through the roof.

What is causing this boom?

I've heard US has diverted its stocks of corn to ethanol and that is
what's causing a big rise in price.  Corn being a staple for livestock
and other things.  So something else had to substitute for corn.
Using that something else then causes a shortage of that item... on
and on it goes.  The result is higher food prices all around.

Also the cost of farming (fuel) has gone up.

Finally speculators have jumped into the market bidding the prices up.

If so, is it fair to say then that high fuel costs are the reason for
high fuel prices?  This is obviously not a case of not enough land to
produce food but energy raising the cost of food production.

Is this correct?