I Have Caterpillars on My Knockout Rose Bushes

Insect-resistant Knockout rose bushes are not immune to caterpillars.

Knockout roses are specifically bred to resist disease and certain types of insect infestation. However, these roses are not immune to all forms of rose bush damage. Caterpillars will eat virtually anything green in your garden, including Knockout rose bush leaves.

Identification

Caterpillar damage is characterized by missing edges on your rose bush leaves. Many moth caterpillar species like to eat rose leaves, but butterfly caterpillars opt for other plant life when available.

Time Frame

Caterpillar damage is most likely to appear in the springtime, as the caterpillars experience multiple growth spurts in preparation for molting.

Solution

A small infestation is manageable by picking caterpillars off of the bushes and relocating them elsewhere. To remedy excessive infestation, use a contact insecticide to kill the caterpillars.

References

• Conrad-Pyle Company: William Radler, Rose Breeder
• "Roses in Gardens"; Alan Toogood; 1990
• "Pests and Diseases"; Andrew Halstead and Beatrice Henricot; 2010