How do I get rid of them?
Yesterday I noticed what i think are rose budworms infesting some of my rose bushes in my garden in Toronto. They are green caterpillars or worms, not more than or not much more than 1/2″ long. They gnaw a hole in rosebuds and eat the bud from the inside. They leave behind a black stringy poop that seems to stick to the rose stems and petals, and also it seems they sometimes leave a little bit of webbing.
I did squish a lot of them, but I think quite a few have pupated as no caterpillar/worm was to be found at some of the damaged areas.
Thank-you for contacting Toronto Master Gardeners with your question.
Roses can be prey to 2 related budworms, the rose budworm and the tobacco budworm. From your description I think your identification is correct. The following link is to an article about identifying and dealing with budworms:
Note that TMG does not recommend chemical pesticides. You could try using an insecticidal soap where you can see the budworms. Hand-picking is also possible but these caterpillars tend to feed at night so it isn’t always possible to spot them when you examine your plants during daylight hours. The good news from the source I consulted is that these insects cause the loss of the season’s blooms, but not the death of the plant.
Good luck with your roses!