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Strange pest on apple trees

Posted by naturewest 5 (My Page) on
Thu, Jan 30, 14 at 21:24

Anybody know what these are? A friend of mine has them all over his apple tree. I'm baffled. They appear to be some sort of worm encased inside of a cocoon made from the material it has mined from the tree. They are attached with webbing, and form a spiral that can be stretched straight. Hope that makes sense.

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Follow-Up Postings:

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RE: Strange pest on apple trees

I am not familiar with this. Send your question to Cornell tree fruit disease expert, Dr. Dave Rosenberger. Email: dar22@cornell.edu


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RE: Strange pest on apple trees

I think it's a form of scale. A dormant spray should take care of it.
Post your picture in the Orchards Forum and you should get a correct answer right away.
mike


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RE: Strange pest on apple trees

Scale. Start by mechanically rubbing it off --if the tree is reasonable size.

If it has that many scale over entire tree, consider replacing it as it has been severely weakened.


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RE: Strange pest on apple trees

Jean, what scale are you suspecting? I've seen and dealt with lots of scale, this is different. It's hard to tell in the pic but it appears that the critter lives inside of a tube made from the frass produced by burrowing into the stem. This cocoon forms a spiral,which makes it look like a snail at first glance. They can be pulled out of the spiral to over a half inch long. I wish I had a picture showing that but I left the branch to prevent spread. I suppose I could make another visit, but I was hoping someone could identify it easily.

Mike and Nandina, thanks for the suggestions, I will take your advice.


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RE: Strange pest on apple trees

My guess is a twig gall. Some are induced by bacteria, but if you have found some sort of larvae in these, I'd say they were insect caused. Which one, I don't know and you should find out. .


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RE: Strange pest on apple trees

As advised, I sent an email to the folks at Cornell and posted in the orchard forum. This is the reply I received:

"From your posted image and description it does not appear to be scale as had been suggested by previous responders. Without an intact sample I would not be able to identify the insect. I too have never seen this structure within the pest complex on apple grown in the northeast.

It appears from your description that the structure is a hibernaculum composed of fine frass and the larva within the spiral case with webbing attaching the case to twigs is likely to be associated with the lepidopteran complex. If larva are within the casing, it seems like a somewhat vulnerable location on the tree and easy prey for other hosts?

Are the apple trees from which these images were take near a forest or other diverse ecology? You could send a sample to the Insect Diagnostic Laboratory, attention of Jason J. Dombroskie, Cornell University, Dept. of Entomology,"

So there you go. I will need to revisit my friend and get a specimen to put in the mail. Unless someone figures it out beforehand. I was hoping this would be much easier!


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RE: Strange pest on apple trees

I'm fairly sure it's a twig gall. I think the Cornell people will agree with Calliope once they get a sample. The picture and some of the description does not match scale.


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RE: Strange pest on apple trees

I agree it looks like a gall similar to what I have seen growing on oak trees in the woods on the leaves and stems


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RE: Strange pest on apple trees

It appears that your question and pictures sent to Cornell attracted someone's attention. Over my years of dealing with them I have never seen such a quick response. Hopefully your friend will save you a trip and quickly send a sample package to the address given for the Entomology Dept. And, will further track and photograph the 'whatever it is' during the spring months and document any damage to the tree.

It is the respondent's statement. "I too have never seen this structure within the pest complex on apple grown in the northeast"
that indicates scientific steps should be followed to exactly solve this mystery which may be a new problem for apple growers.

Please keep us updated.


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RE: Strange pest on apple trees

Yay! Mystery solved. Kudos to the brains at Cornell:

' The photos appear to be of snailcase bagworm, Apterona helix. A European native, at least in NY it is in the Capital District (I have seen it in one area east of Albany on white pine but there are reports elsewhere). I have also seen it in one nursery here on Long Island. So far here it hasn't become a serious pest. IT is a strange type of moth, parthenogenic (reproduces without mating) and have many host plants including deciduous and coniferous species.

The larvae chew up bark, soil, and other matter to attach to silk, forming the snail-like cases. The larvae overwinter. You'll probably see some leaf damage where they are present. The cases can be annoying when they crawl up to overwinter attached to homes or structures.

Blasting off with a jet of water, application of a labeled residual insecticide in season (choose according to whether on a plant or a structure), or use of other product labeled for caterpillar control (Btk, others) should control them. Of course be sure a product is labeled for that particular use.

Here are some factsheets on-line:
http://www.msue.msu.edu/objects/content_revision/download.cfm/revision_id.277911/workspace_id.-30/Snailcase
http://cru.cahe.wsu.edu/CEPublications/FS020E/FS020E.pdf
http://ento.psu.edu/extension/factsheets/snailcase-bagworm

Dan Gilrein
Extension Entomologist'

Here is a link that might be useful: Snailcase bagworms


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RE: Strange pest on apple trees

having finally read the links above.. i think ... if it need be said..

that you ought to inform your county Ag extension office immediately ...

they might be very interested in this little known problem ...

if you dont want the gubment involved.. then perhaps removal and burning is the next best option ... this usually solves such type issues ....

are you in WA ?????

ken


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RE: Strange pest on apple trees

Thank you so much for posting the follow-up of your findings, and doing the right thing by submitting samples. Finding pests in new territory is always disconcerting.......sigh.


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RE: Strange pest on apple trees

Ken,
I sent a link to this thread to our county extension office. I should've known, because he is REALLY good, that he was already aware of this pest. He sent me the link below:

http://ag.arizona.edu/yavapai/anr/hort/byg/archive/snailcasebagworms.html

Here is a link that might be useful: Snail case bagworm


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