Return to the Dahlia Forum | Post a Follow-Up

 o
Stem Borers- Anyone Have Them Yet?

Posted by dahliaboy 6A (My Page) on
Sun, Jul 22, 07 at 7:55

Hi All:
I was away on business for a little over two weeks and
came back to some stem borer damage to a few of my dahlia
plants. These particular borers were from a moth. I've
attached some photos of the damage and the culprit.
Usually the moth will lay her eggs on the stem of the leaf close to the stalk. The larvae will bore into the plant and eat away until they are mature enough to exit. They destroy the vasular system of the plant and cause a wilt in the affected branches/stalks. You'll also notice their frass in the crotch where the leaf meets the stalk. You can usually cut off the affected stalk and move on.
DB

Photo Sharing and Video Hosting at Photobucket
Here's the wilted stem

a href="http://photobucket.com" target="_blank">Photo Sharing and Video Hosting at Photobucket
The Frass

a href="http://photobucket.com" target="_blank">Photo Sharing and Video Hosting at Photobucket
The Frass Inside

Photo Sharing and Video Hosting at Photobucket
The Culprit

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket
The Exit Hole


Follow-Up Postings:

 o
RE: Stem Borers- Anyone Have Them Yet?

  • Posted by jroot 5A Ont. Canada (My Page) on
    Sun, Jul 22, 07 at 21:39

an excellent lesson with photos. THanks for sharing.

So far, I have avoided this pest.


 o
RE: Stem Borers- Anyone Have Them Yet?

Had that once
I beleive it is the same borer as the squash vine borer.
hard to get rid of. eggs should be at the base of the plant - rusty red disks. I squish them.

I am sure you know what to do DB, just putting in my 2 Cents.


 o
RE: Stem Borers- Anyone Have Them Yet?

Great photos. I was cowering in the dahlia beds today hoping I wouldn't find any wilted stems.

DB you might offer to share your photos with www.dahlias.net or the ADS website or other. I think it would be a great addition to their pest information sections and a service to all dahlia growers with those excellent photos. Just a thought...


 o
RE: Stem Borers- Anyone Have Them Yet?

DB, if the disgusting worm is nowhere to be found, how do you differentiate between a stem boring problem and stem rot?? I've had several wilting problems but I don't know what it's from. I don't know how to post pics on here so I just included the link at the bottom. Anyone with any answers or ideas, please advise!!! Thanks!

Tracy

Here is a link that might be useful: stem rot


 o
RE: Stem Borers- Anyone Have Them Yet?

Tracy:
The way you will know if it's a stem borer is if you see an exit hole like I show and the presence of Frass which is the excrement of the larvae. Look at photo #2 and you'll see where to look for the frass.
DB


 o
RE: Stem Borers- Anyone Have Them Yet?

I see...thanks for the useful info!!


 o
RE: Stem Borers- Anyone Have Them Yet?

May I revive this topic? I wonder if Bonide's "Eight" will work on this critter. Has anyone tried it?

Pat


 o
RE: Stem Borers- Anyone Have Them Yet?

Yes you may revive and in answer to #2 I just don't know.

However, I was wondering what has happened to DB. I brought a pal to one of his talks and now she is an avid dahlia gardener. I have people who want to talk with him about a lecture.


 o
RE: Stem Borers- Anyone Have Them Yet?

I am so glad you found the culprit. I hate to think of what happened to him. Bird food? Anyway, can you use something to avoid the borers or is it luck?


 o
RE: Stem Borers- Anyone Have Them Yet?

Hey Misslucinda,
I'm here......been busy with work, house renovations and
planting my 200 dahlias.
DB


 o
RE: Stem Borers- Anyone Have Them Yet?

Hey DB-

Glad to see you are still checking into the forum. If you are doing house renovations, you must be doing well!! I'll forward your telephone to the member of the local GC Program Committee who inquired.


 o
RE: Stem Borers- Anyone Have Them Yet?

Misslucinda:
Sounds good...Best months for me to talk are Sept
and Oct.
DB


 o
RE: Stem Borers- Anyone Have Them Yet?

So - Bonide's Eight....worth using?


 o
RE: Stem Borers- Anyone Have Them Yet?

Thank you for the wonderful photos, DB. That's the lil bugger that destroyed my squash crop this year. Borers not bad last year (cause of GA drought?) but this year they're huge problem (still in drought but had more spring rains).
I'm horrified you are showing them in dahlias. My dahlia bed is hop, skip, jump, and short moth flight from veggies to dahlias.


 o
RE: Stem Borers- Anyone Have Them Yet?

  • Posted by jroot 5A Ont. Canada (near (My Page) on
    Wed, Jun 25, 08 at 7:21

I have a couple that are wilting, but their neighbours are not. Your posting made me curious, so I went out to see if there was evidence of holes or frias. I can't see any. The ground seems to be not dry, and yet, if I put water on it, the plant picks up. Strange. I'll keep my eyes open, and maybe replace the culprits.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Dahlia Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here