Trish,
Alocasia berries are ready to harvest when they are orange-red and slightly soft to the touch. You can also know they are ready when the portion of spadix surrounding the developing berries peels away by itself to reveal the ripe berries. The whole process from pollination to harvest is usually about two months in good weather - cool weather will slow the process.

LariAnn
Aroidia Research

Here is a link that might be useful: Ripe Alocasia berries (top picture)

Thank you so much LariAnn! I had my first flower last week... I did not pollinate it as I had no pollin... Will it still make the berries? I am new to alocasias...
Trish

Trish,
In most cases it won't make berries, but I have had some make berries without my help because bees or other insects did it for me. I've had three different Alocasias put out berries without my assistance, but most of the time they don't.

LariAnn