Currently viewing the category: "Grubs"

Subject:  What am I and can i kill trees?
Geographic location of the bug:  Millican Tx
Date: 01/30/2018
Time: 10:01 AM EDT
Your letter to the bugman:  Hello, recently i hauled off a dead tree from my mothers house and while cutting it up for firewood, found this Larva stage looking fellow.. id like to know what kind of insect this is and is it capable of killing trees once it burrowed in or was it just looking for a spot to metamorphosis?
How you want your letter signed:  Thanks! Vivian Stanley

Beetle Grub: Cerambycidae or Buprestidae???

Dear Vivian,
This is a Beetle Grub, most likely from either the Longhorned Borer family Cerambycidae, or the Metallic Borer family Buprestidae.  A single grub will not kill a tree, but a serious infestation might compromise the health of a tree.  You did not indicate what type of tree it was since many Borer Beetles are very host specific.  Additionally, you did not indicate the size.  Immature Grubs can be difficult to identify with certainty, and we cannot see enough features, including the head, to help narrow down the possibilities.

Thanks so much for your speedy response, i truly appreciate it. The information you’ve provided will be most helpful indeed!!

Subject:  Grub
Geographic location of the bug:  San Diego coastal 15″ below ground
Date: 01/20/2018
Time: 08:00 PM EDT
Your letter to the bugman:  I’ve never encountered a grub so large before and would like to know what kind of beetle this will become.
How you want your letter signed:  Matt Lee

Prionid Larva

Dear Matt,
This appears to be one of the Root Borers in the subfamily Prioninae.  Was there a tree or shrub nearby, or perhaps the trunk of something that had died?  While we are reluctant to provide a definitive species identification, it might be the larva of a California Root Borer like this image posted to BugGuide.  According to BugGuide:  “Larvae: Up to 80mm long” and “Larva feed primarily on living deciduous trees (oaks, madrone, cottonwood) and are also recorded from roots of vines, grasses, and decomposing hardwoods and conifers. Will also attack fruit trees growing on light, well-drained soils (e.g. apple, cherry, peach).”  If that is a correct identification, here is an image of an adult male California Root Borer, though your larva might belong to a different, though similarly large Prionid with long antennae. 

Prionid Larva

Subject:  Mystery Grub
Geographic location of the bug:  Orange County, CA
Date: 12/02/2017
Time: 12:49 AM EDT
Hello.  I moved a tent in my backyard and found many of these grubs.  One of the ones was much bigger than the others.  You can see it in the photo compared to my thumb.
How you want your letter signed:  Michael

Scarab Beetle Grubs

Dear Michael,
These are Scarab Beetle Grubs.  Many species feed on the roots of grasses.  Others are found in or near decaying vegetation, including in compost piles and rotted logs.  We are postdating your submission to go live near the end of the month when our editorial staff is on holiday.

Subject:  Coleoptera larva?
Geographic location of the bug:  Serengeti in Tanzania
Date: 11/30/2017
Time: 02:58 PM EDT
I’m not sure but possibly it’s a coleopteran larva. I’ve been searching by Internet but it’s been impossible to find any larva like this one.
Can you help me?
It was in may 2016.
How you want your letter signed:  Ferran Lizana

Larva, probably Beetle Larva

Dear Ferran,
Except for butterflies and moths, there is often not much documentation available on immature insects.  We agree this is probably a beetle larva.  We are posting the image and perhaps our readers will want to take a stab at this identification.

Subject:  Wood borer in finished hardwood floor.
Geographic location of the bug:  Brant County near Grand River & Brantford. ON
Date: 11/18/2017
Time: 10:25 AM EDT
Per attached pictures, grub was located by blowing out fine white sawdust from 3.25″ long bore hole and injecting wasp an hornet foam insecticide into the hole to the depth of the hole. The grub moved to the entrance and was removed. The hole was discovered when the surface of the floor sank and in probing the very thin wood and varnish were lost. Further slivers were raised in probing the hole. Can you identify the species?
How you want your letter signed:  Gord Burkholder

Round-Headed Borer

Dear Gord,
Unfortunately, the image of the Round-Headed Borer is considerably less well focused than the image of the wood damage, but even if the image was better quality, we would most likely not be able to provide more than a family identification.  Round-Headed Borers are the larvae of Longicorn Beetles in the family Cerambycidae, and knowing the host plant might be helpful.  What we can tell you is that the larva was most likely already in the wood when the tree was cut, though sometimes the beetles will lay eggs in freshly cut logs.  We can state with relative certainty that the larva was already in the wood by the time the lumber was milled.  Longicorns do not infest milled lumber, so you do not need to worry about further damage, unless there were other larvae in the wood prior to milling.  Do you know the type of hardwood and the location where the trees were grown?  That might help with a more definite identification.  We have heard of incidents when adult beetles will emerge from lumber milled many years in the past.  You might find interesting information on the article entitled “Identification of wood-boring beetles (Cermabycidae and Buprestidae) intercepted in trade-associated solid wood packaging material suing DNA barcoding and morphology” where it states:  “Global trade has created a pathway by which nonnative species may cross once impervious natural borders such as oceans and mountains.”  That site acknowledges “The larvae depicted are visually similar and are difficult to identify below the family level. “

Wood Damage

Thank you Daniel;
I should have added more info. The floor has been down almost 8 years and the oak came from Quebec. There have been no other indications of other infestation. Part of the house heating is done by a wood stove and I have some concern that the species may have been introduced from the firewood.
Gord Burkholder
Hi again Gord,
We are relatively confident this individual was in the wood at the time of milling and not introduced from firewood.

Subject:  Beetle lava in oak?
Geographic location of the bug:  Tarn region, South West France
Date: 10/16/2017
Time: 05:48 AM EDT
I found a lot of my woodpile is being attacked. The bark is eaten away and there are lots of holes in the wood. I split a log and found the bugs inside – they are about half an inch long. They have only attacked the oak, so far, but I am a bit worried in case they attack any other or structural wood and cause damage. Hopefully they are just big beetles, but please identify them if you can. Thanks.
How you want your letter signed:  Phil

Longicorn Pupa

Dear Phil,
This is a pupa of a Longicorn Beetle in the family Cerambycidae.  These beetles will attack weakened trees and freshly cut firewood, but they generally do not infest milled lumber, unless the larvae were developing in the wood when it was cut.

Longicorn Pupa

Hi bugman Daniel,
Thanks for your speedy reply and for answering my question. Great service! I think your website is fantastic, with so much info there – you must be really fascinated by all these bugs.