Confirmed: Sawfly Larvae on Disneyland Roses. Treatments and Planning - December 2023
Earlier this growing season, I discovered that most of our Disneyland Roses were having their foliage destroyed by someone or something. The leaves were spotted and some of them were eaten-up and looked like lace. Here's a post from June 2023 that shows one of those eaten-up leaves.
I applied a granular fertilizer all season - starting in early Spring - and I wasn't sure if the foliage damage was a result of the granules clinging to wet leaves, but it seemed far-fetched.
The foliage-eating continued all season, but by July, I decided to take some action and switched from just straight Rose Fertilizer to a 2-in-1 feed and care product from BioAdvance. My hunch was that SOMETHING was eating the leaves and the 2-in-1 is a 'systemic' product. That means it isn't something that takes root immediately and eliminates the pests. Rather, it feeds the roses and - via the roots - takes up the insecticide and carries it to all the plant material. I've used a similar product to treat aphids in our Lindens and Scale on our Saucer Magnolia over the past few years.
By Summer, I was pretty sure it was Sawfly Larvae. See this page showing the very thing I was seeing on my roses. Then, I spotted one: a small green worm on one of the leaves. I squished it. But, it was then that I *knew* what I was dealing with on the roses.
That meant that I continued with the 2-in-1 systemic treatment. That wasn't going to kill the pests immediately, but would help over a longer period of time.
To go at them immediatly....I also added a new trick to my pest plan: Neem Oil. I bought a small bottle of concentrate and mixed up my own batches. This Captain Jack's Neem Max (from the orange big box store) lists Aphids (Lindens), Scale (Magnolia) and Sawfly Larvae (Roses), so it covers all the pests:
The Sawfly Larvae persisted until the season ended, so I attempted to blew away as many of the fallen leaves before mounding the biosolids for Winter protection.
For 2024, I'm going to try to get ahead of the pest by starting the season with the systemic 2-in-1 with an early feeding and continue to use that product all season long. From there, I'll apply Neem Oil and monitor the foliage closely. If need be, I'll start to look into other solutions - things like Sevin - that I hesitate to use.