How to Spot Rose Sawfly on Your Roses

 

lightly damaged rose leaves by sawfly

A friend of mine has some roses that I noticed looked a bit brown. Upon closer inspection, the leaves looked skeletonized, like the damage a Japanese beetle does, but this was sucked dry, but not chewed through. It’s also a bit too early for Japanese beetle. Keep looking…

The rose sawfly has one generation a year, with larvae appearing in mid to late spring.

sawfly larvae on rose leaf

The larvae fall from the plants and tunnel into the soil by mid-June, but it’s a bit earlier this year.  They remain dormant underground until next spring, when the adults emerge and lay eggs on the new rose foliage to begin the cycle over again.

saw rose fly larvae

Larvae can be effectively controlled with a neem oil product or an insecticidal soap. Spray only the leaves (both sides), in the morning as neem oil can possibility hurt pollinators (More research needs to go into that). The strategy is to find larvae while they are still small and before damage becomes severe, like my friend’s roses! There is no need for control after the larvae have finished eating and left the plants, give or take mid-July.

One last note, these are not caterpillars, they are actually primitive wasps, so Bt or Bacillus thuringiensis will not work.

© The Naturarian

11 thoughts on “How to Spot Rose Sawfly on Your Roses”

      1. Oh I’m sure we have something similar. One thing I have found here – our climate makes the plants (and weeds) grow really well, but it also makes the bugs prolific! 😀

        Liked by 1 person

    1. I answered your comment b4 another comment came in about the sawfly origins. I’ll c&p here :
      I’m not an entomologist (Jim 😉), I only know the basics:
      Identify plant. Identify bug. Kill bug. 🤣
      There are many (over 7,000!) types of sawfly.
      The largest family (5,000) are found worldwide (no Antarctica) but concentrated in Northern hemisphere.
      The next largest (800) does hang out in hotter regions like your hood.
      Most sawflies like a specific plant. So, in lieu of truly naming the bug down to the species, we (horticulturists) name the general bug (sawfly) and the plant it bugs (rose).
      I’m guessing that this bug could actually be one of 3 – 5 different types that like roses. But, for me, they all die the same way 😏

      Liked by 1 person

    1. Good question! 🤓
      The US has 20 native roses, some rare, all single petal types that look nothing like the common concept.
      All other roses came in via Europeans.
      The sawfly (aka wood wasps) origin is a bit tougher…
      I’m not an entomologist, I only know the basics:
      Identify plant. Identify bug. Kill bug. 🤣
      There are many (over 7,000!) types of sawfly.
      The largest family (5,000) are found worldwide (no Antarctica) but concentrated in Northern hemisphere.
      The next largest (800) does hang out in hotter regions like your hood.
      Most sawflies like a specific plant. So, in lieu of truly naming the bug down to the species, we (horticulturists) name the general bug (sawfly) and the plant it bugs (rose).
      I’m guessing that this bug could actually be one of 3 – 5 different types that like roses. But, for me, they all die the same way 😏
      Hope I answered your question!

      Liked by 1 person

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