Worms perforating leaves on rose bush(es)

(Question)

Some worm-like insects are enjoying the leaves on a rose petals, just as the petals are beginning to bloom. I didn’t photograph the leaves which are more perforated, and there are about 5 other leaves, which have round holes.

I flicked off the worms, which have little reddish or orange caps. There are two in this photograph, which shows a different eating pattern if these are the source of the leaf damage.

Are there any simple remedies, other than watch them and remove them?

Also, can more than one picture be submitted, in the future, for the same query? I wanted to show the other leaves, but they were in a different part of the bush.

Thank you

(Answer)

I suspect your unwelcome guest is the “rose slug” or larva of the sawfly. Here’s an image courtesy of the Missouri Botanical Garden.

Adult sawflies emerge in early spring and lay their eggs on the underside of host plant leaves. Larvae appear several weeks later, feed on soft leaf tissue for about a month, and then drop into the soil to pupate.

The Botanical Garden recommends early detection to get the pest under control.  Begin looking for sawfly larvae in mid-spring  Inspect both upper and lower surfaces of the leaves. Remove the infested leaves and destroy the larvae. A forceful spray of water out of a garden hose can also provide control by knocking off and killing many of the soft-bodied larvae. Be sure to aim the water at both upper and undersides of leaves. When the larvae are still very tiny, apply insecticidal soap as per the package direction. For larger larvae, removing and hand “squishing” is advised. Continue checking plants throughout the growing season.

Thanks for sending your photo. When you have several to send us, we find that sending them as separate posts works best. When we publish the question and answer, we will include as many photos as we think are needed.

Good luck