Return to the Gardening in Canada Forum | Post a Follow-Up

 o
large rose sawfly and dormant oil??

Posted by clareqc quebec..chelsea (My Page) on
Tue, Apr 25, 06 at 7:53

I have some rose bushes that have been hounded by large rose sawflys the past few summers and I am wondering if dormant oil spray would help to lessen their numbers.
I understand they overwinter as pupae in the soil?? and hatch into adults in the spring. There again to begin their cycle?
So if these are the facts can I use dormant oil spray to stop their growth and can I spray around the plant, say the base and the soil?
Not sure what else to do as I am loathe to use other chemicals...
Help...


Follow-Up Postings:

 o
RE: large rose sawfly and dormant oil??

I don't know if or where the adults overwinter, but I believe the eggs are laid in the shoots, and the larvae emerge in the spring. If they were in the soil then dormant oil would be of no use. If your rose is beginning to leaf out, as the ones around me are, then an application of dormant oil right now will harm the leaves. It is supposed to be of some use in controling sawflies though, when used at the right time (before budbreak). So it might be something to consider for next year (unless you're a lot further north than I am).

For now, handpicking of the larvae is quite effective if you are religious about it. Keep a tin of soapy water handy, and do a quick check as often as you are able, tin in hand. Pick the larvae off and drop them into the tin. Check the underside of the leaves.

The larvae usually show up in mid to late May around me, but they might be a bit early this year because we've been so warm.

BP


 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 Gardening in Canada 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.
  • 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