Repulsing the Repulsive

We moved to Canada a handful of years ago and the first summer we lost a bush.  I don’t mean we couldn’t find it but it was devoured and rendered a corpse.  It smelled like one too.  That first year we thought that was the intended smell of that particular plant but I dug it up and we tossed it because it looked like it had had it.  It wasn’t until the next year that we realized we had an infestation.

The first I noticed of it was a small, green and black caterpillar appearing on my rose bushes.  I’m more of an avid gardener than a good one but I love roses and always try to shock some of them out of the ground at each of the homes we’ve had.  I am sure I have inherited this from my father, who grew lovely ones and even showed them off at flower shows . I have no such aspirations but that does not mean I bear any love for bugs that eat my flowers.

And that’s what these things did.  They quickly multiplied and ate through massive numbers of leaves.  Pretty soon, my lovely green stalked roses were turning brown as though someone had held them over a campfire.  They weren’t exactly burnt but there was no life left in them.

I was able to identify them, thanks to the Web, as saw fly larva.  The only solution for killing them was “the sensation of a short, sharp shock” although we dispensed with the chippy, chippy chopper.  If you have young boys, they will be happy to help.  Mostly this involves finding the culprits and squishing them between your fingers.  Guts pop out and fun is had by all.

Fortunately, everyone survived except the larva:  the boys looked forward to gardening and we caught the problem before the roses were beyond recall.  After some research, we were also prepared for them the following year.  Sure enough, late May, early June, the little perishers started to appear.

Rose bud that has been partly devoured and black dots along edge of leaf.

Now I can see them before the larvae even emerge.  There are some tell-tale signs:

  • They always appear on buds, so I look there first;
  • They always emerge from a bud and leaves that look like they’re covered in very fine spiders web;
  • The leaves and spider web material have lots of black dots on them

When the time comes each year, we now snip off any buds and attendant leaves that exhibit this web and black dust.  This is the third year of this process and we have only had 2 larvae successfully emerge this year.  Or at least, that’s all the boys have had to squish.  I have seen some other evidence of larvae but the leaves that have damage no longer have a caterpillar-looking resident.  Since there is a bird feeder right beside the roses, I am hopeful that the larvae are becoming an after dinner mint for some lucky starling.

If you have this invader, it can be a real pain.  But we’ve gone through nearly losing our roses to having very little problem in about 4 years.  Once you cut the serpent’s head off, there’s no more activity that year and your roses can bloom without further disagreeable interruption.  It also appears to have lessened each year, which I’m sure some 5th grader could explain to me in simple terms.

David Whelan

I improve information access and lead information teams. My books on finding information and managing it and practicing law using cloud computing reflect my interest in information management, technology, law practice, and legal research. I've been a library director in Canada and the US, as well as directing the American Bar Association's Legal Technology Resource Center. I speak and write frequently on information, technology, law library, and law practice issues.