I have make two farm with an harvester and ic2 crops

the harvester harvest on my test only the sugar canes.
I have testet it with sugar canes and potatos.

IC2 crops are all handled identically; if it works on one it works on all of them. Wait for the potatoes to mature.

In FTB Resurrection ( MFR 2.8.0RC5-694) The harvester doesn't get the ic2crop potatos until they get to the very last stage.

The problem is that ic2crop potatos go through the normal growth and mature, but their last stage is poisonous potato.

So the harvester waits until they turn to poisonous potatos, which takes a while.

That also means the harvester cannot ever get normal potatoes from ic2 crops

Then this is a flaw in IC2's crop system that makes automation difficult. Don't use potatoes until IC2 gets fixed.