Beech hedge query

Derek White asked 5 years ago

I’m trying to identify the “critters” in the pics. I discovered them when replacing some beech hedge plants. There are 40 plants in the hedge that was planted bareroot in march 2016, each plant was about 5ft in height when planted, so reasonably mature. I had to replace 10 of them, which i did January 2017. The 10 replaced were not all in the same place, although a few were next to each other.I’m wondering what the critters are and if they could be a problem and were a factor in the plants dying, of course the plants could have died as a result of how I planted them. If they are a problem how should I treat them?See also pic of one of the dead plants,there are white specs on the roots, first I thought it was just residue of blood, fish and bone but that was applied during last summer and would’ve surely dissolved?I was only able to attach one pic