Garden Pests and Diseases: Pecan tree grub, 0 by FlaFlower

FlaFlower wrote:
Ok, so we moved into this house just about 4 years ago, it has a few mature trees on it (all are about 50 years old) one being this pecan tree which is in poor shape and I have been trying to save it threw correct trimming, good food, watering and what not. So this tree went from about 60 foot to 30 foot threw last 4 years of trimming some the first year and then this year we decided it would be ok to trim it again since it had rebounded so well and even gave us some decent pecans this year, we were stoked to say the least!
Well, we decided to keep the trimmings and use as fire wood in the outside pit, as my wonderful husband was spilting wood here come these grubs!
They are HUGE...my questions are:
#1. Is this grub destroying my tree from the inside out or did something deposit the eggs after the tree limbs were cut down and piled.
#2 What is it? I am not sure the orange one is the same type as the others since it has different mouth parts and legs, the white ones don't have legs. Let me know if I am wrong.
#3 How do I treat the tree for these icky things if it is infested, I would really like to save this tree.

Thanks for any help Floridaheat