It's because the word "biodiesel" has four syllables, and that's just too many for GWB.

Ok... That was mean... But I *am* an unabashed socialist hack, after all, ha ha!

But seriously, he probably didn't mention it because that word probably just isn't part of the average American's vocabulary. If he'd mentioned it, he'd have a bunch of conspiracy nuts thinking he's planning on using genetic engineering to make tractor fuel (or something like that).

 

He mentioned bio-d in his last State of the Union address.

 

Cool! I'm glad that he covered all the bases.