White grubs eating potatoes - how to prevent for next year

Our community garden is freshly converted turf that had no chemical management in the 5+ years prior.  In our first year, many of plots are reporting white grubs eating the potato tubers.  

What can I tell the gardeners for next year?  Is there something permaculturalish that we can do?  Will they get better or worse with time?  

White grubs should diminish drastically with time out of turf. If it were my garden, I'd winter fallow plots intended for potato next year, then pay attention during spring planting and any other soil disturbances to pick out evident larvae. These transitions from perennial crops to potato are usually tricky because of grubs, wireworms, and similar.

Thanks Andy, that makes sense!

Jup just wait and do not allow grass to grow as a weed. I have the same issue with wireworm, unfortunately they can take 5 years to vanish.