Roses: rid of Japanese beetles/ prune after attack - Knowledgebase Question

Aurora, oh
Question by jillbrown1
August 15, 2007
How do I get rid of Japanese beetles?! I've tried the spray, the powder and the bag! I've even flicked and picked them off by hand and squished the pests! Aside from select, partially eaten leaves my roses seem healthy but my climbing rose won't bud and bloom. Any ideas?

Answer from NGA
August 15, 2007


Japanese beetles are difficult to control, in part because they fly long distances. The pheromone traps are not recommended because they actually seem to attract more than they catch.

You can try to repel the beetles using a spray containing neem, or you can handpick them (they are sluggish early and late in the day), or you can spray with spinosad or with carbaryl (the active ingredient in Sevin) but keep in mind this is a contact insecticide with no residual action.

You can also use beneficial nematodes or a neem based product sprayed on the lawn in late summer to early fall to kill them at the grub stage. Milky spore disease in granular form can also be applied to the lawn and a treatment lasts in the soil for many years, but it takes some time to see results. Be sure to read and carefully follow all of the label directions on any product you use.

Unfortunately, most gardeners find they have to tolerate a certain amount of damage, and some years are more severe than others depending on the weather and other conditions.

You might be interested in reading the following recent release from Penn State about using alternative methods to control the grubs.

As far as the climbing rose, you might want to review your pruning routine. Many of these bloom on canes that grew the year before, so the pruning is different than it would be for your typical hybrid tea rose bush. Also, extensive winter damage can limit flowering so you might want to consider taking special protective measures such as burying the canes or trying to wrap them. Finally, be sure the climbing rose is considered winter hardy for your zone.

I hope this helps.

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