The past few years have been difficult for rose growers in the Midwest region due to an increase in Japanese beetle (Popillia japonica) populations. Japanese beetles can cause damage to many different areas on the rose plant. Their first target is normally the rose bud, feeding on pollen. Damage appears as a small, round hole going through the side of the flower bud. Buds that are able to fully open are normally the next target. The damage to the flowers is a small hole in the flower petals. As beetle populations increase, and after the first bloom of the rose is finished, they begin to attack the foliage. Typical damage to the foliage ranges from small holes in the leaf to complete destruction, resulting in unattractive plants in the landscape. In recent years, because of the Japanese beetle problem, homeowners are eliminating roses from the landscape. An efficient way of getting rid of these pests is needed.
Iowa State University
Strey, Daniel J.; Christians, Nick E.; and Howell, Nicholas P., "The Use of Imidacloprid Patches to Control Japanese Beetles on Roses" (2014). Iowa State Research Farm Progress Reports. 1997.