Q. There are holes in my rose leaves. What's happening?

Answer

The jagged, irregular holes on your rose leaves are made by sawfly larvae. These pests look like little green caterpillars, but they are the larval stage of a wasp-like insect. Because they feed from the bottoms of leaves in the early morning, sawfly larvae can be difficult to spot.

As they are not caterpillars, the larvae are not affected by caterpillar insecticides. To control them, either hand-pick them or spray infested plants with an insecticidal soap spray. Spray the plants thoroughly when you first see the larvae, and check for a second generation to keep the population down. For an easy corrective in early spring, cultivate the soil beneath your roses to expose the pupae to predators and the weather. There are homemade spray recipes you can make if you prefer. Rodale provides an organic recipe, but remember that soap-based sprays may harm beneficial insects and natural enemies that patrol the bad insects. 

See Cornell's Attracting Insects' Natural Enemies for guidance on attracting beneficial insects to your garden. Also see our Companion Planting LibAnswer for more information on deterring "bad" bugs.

Does companion planting help deter bad bugs? Ask this question in the libguide portal page.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service

  • Last Updated Apr 02, 2018
  • Views 46
  • Answered By Anita Finkle

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