How do I get rid of Japanese Beetles? - Ask Extension
How do I get rid of Japanese beetles. They are eating roses and other flowers in my garden. Should I use Beetle traps. My neighbor says no.
Knowledgebase
How do I get rid of Japanese Beetles? #877811
Asked July 18, 2024, 3:18 PM EDT
How do I get rid of Japanese beetles. They are eating roses and other flowers in my garden. Should I use Beetle traps. My neighbor says no.
Boulder County Colorado
Expert Response
Hello Mary, Unfortunately, Japanese Beetles are nearly impossible to control.
Unfortunately, Japanese beetle traps are ineffective for control where Japanese beetle is well established over a large area, common now in many Front Range locations. Repeated trials have demonstrated that use of such traps does not reduce the number of beetles damaging nearby vegetation. Furthermore, the use of Japanese beetle traps often increases damage by Japanese beetles by drawing into the vicinity larger numbers of beetles than are captured in the traps. Because of this Japanese beetle traps are not recommended for Japanese beetle control.
Hand picking beetles can sometimes be effectively employed in small plantings. The beetles are easily picked or dislodged; shaking infested plants over a collecting container in early morning when temperatures are cool can be particularly productive. The regular removal of beetles prevents the feeding damage produced by the beetles, which can reduce the production of chemicals produced by wounded plants that are attractive to the adult beetle.
For more information, please see https://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601/.
I am a rose gardener myself. For years now I have been resigned to having a bountiful bloom cycle in May and June before the beetles emerge from the ground. Then, if we're lucky, we'll have another beetle free season in September. In July and August, I remove nearly all my blooms along with the numerous beetles on them.
Jim, CSU Boulder County Master Gardener Volunteer
Unfortunately, Japanese beetle traps are ineffective for control where Japanese beetle is well established over a large area, common now in many Front Range locations. Repeated trials have demonstrated that use of such traps does not reduce the number of beetles damaging nearby vegetation. Furthermore, the use of Japanese beetle traps often increases damage by Japanese beetles by drawing into the vicinity larger numbers of beetles than are captured in the traps. Because of this Japanese beetle traps are not recommended for Japanese beetle control.
Hand picking beetles can sometimes be effectively employed in small plantings. The beetles are easily picked or dislodged; shaking infested plants over a collecting container in early morning when temperatures are cool can be particularly productive. The regular removal of beetles prevents the feeding damage produced by the beetles, which can reduce the production of chemicals produced by wounded plants that are attractive to the adult beetle.
For more information, please see https://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601/.
I am a rose gardener myself. For years now I have been resigned to having a bountiful bloom cycle in May and June before the beetles emerge from the ground. Then, if we're lucky, we'll have another beetle free season in September. In July and August, I remove nearly all my blooms along with the numerous beetles on them.
Jim, CSU Boulder County Master Gardener Volunteer
