I'm playing the ATM8 modpack and I spent far too much time trying to get the harvester pylon to work. I found that the harvester pylon doesn't seem to recognize crops grown on the mystical agriculture farmland. I don't know if this is a bug or intended, but I thought I would mention it.

The farmland should not matter - do you have the pylon in the water block or above it, and what type of crops are you growing?

Sorry I got it working. I restarted the game and it started working correctly.