Pest Watch: Rose Slug Sawfly

A pest to watch out for this time of year is Rose Slug Sawfly (Endelomyia aethiops). It can be a nasty pest of roses in late May/early June. The pest gets its name from its ability to lay eggs in plant leaves or stems with a saw-like egg laying mechanism. The worm-like larvae are greenish yellow with orange heads, reach a half inch in size and have a similar appearance to caterpillars. They will skeletonize the upper surface of rose leaves, sucking out the soft tissue and creating translucent patches in between the veins that will eventually turn brown. Regular inspection of roses is crucial because feeding typically progresses quickly, and extensive leaf damage can occur if infestations are not noticed. What can be done if damage is seen? Hand removal can be effective if caught at the right time. Insecticidal soap can be used for low populations of young larvae. More severe infestations can be controlled with neem oil. If you know that your roses are prone to this pest, we can spray a preventative application of neem, before any damage has been done. Soil amending is critical in rose gardens, as soil microorganisms can then thrive in a healthy balanced soil and attack eggs of this pest before the larvae have a chance to emerge. Typically, the roses will re-leaf. Only one generation per year emerges from the soil. If leaf damage is seen,  right away to arrange spot spraying.