Beetles are attacking my Rose of Sharon!

11 years ago

I have beetles feasting on the blooms of a Rose of Sharon Helene. The blooms are wilting and dying. The beetles are even trying to eat the ones that haven't opened yet. I believe the beetle is the "dogbane leaf" beetle. Should I try to get these beetles off? If I should, how would I go about it? Any help would be greatly appreciated! This shrub means a lot to my wife, as it was planted in memory of her mom. Thanks much!

Featured Answer

rhizo_1 (North AL) zone 7

11 years ago

Japanese beetle season doesn't last very long, thankfully. Neem is not the broad spectrum pesticide as kimmsr misunderstands it. The beetles won't be harmed outright by an application, as a matter of fact. But neem does act as a very successful anti-feedant! Neem is not a contact killer but needs to be ingested by the plant feeding pest. It is a very useful tool in organic pest control.

What I might do is to apply a mix of insecticidal soap (for instant knock down) and neem. You can purchase such a combination already prepared or follow one of many recipes found on line. You must follow the directions on the label or labels (if you do a tank mix) to avoid damage to the plant by spraying in the heat of a sunny day. You must avoid spraying open flowers which may be
Visited by pollinators.

I'd only use the soap if beetle populations are very high. It might be that one application of an anti-feedant will do the trick!

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Comments (8)

rhizo_1 (North AL) zone 7
11 years ago
Look up Japanese Beetles and see if that's not the culprit on your Rose of Sharon. Dogbane beetles are pretty species specific and will be found on milkweed and....dogbane.

Japanese Beetles are common pests of a wide variety of plants, including yours.
segercasey
Original Author
11 years ago
Hello rhizo_1, I did just that and you are spot-on - they are Japanese beetles. I noticed several remedies, but none sound too promising. Any suggestions?
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Kimmsr
11 years ago
The most environmentally sound method of control is to go out early in the morning, while these buggers are still to sluggish to move around, and knock them off into a bucket of soapy water. Next up would be spraying them with an Insecticidal Soap, followed with either Neem Oil or a pyrethrin based spray. Both of those are broad spectrum poisons that can adversly affect the beneficial insects so due care in use is needed.
ken_adrian Adrian MI cold Z5
11 years ago
first and foremost.. get it in your head.. that there is a 99% chance.. that they will have NO long term affect on this plant ... they may make plants look ugly.. but they rarely kill them ...

and then next... consider the extended drought and heat wave.. as the cause for wilting flowers..

i just noticed last night.. that my 6 ROS are severely stressed due to such ...

in other words.. though they are eating the flower .. and aggravating you ... you may have other.. underlying problems ..

ken
segercasey
Original Author
11 years ago
Thank you everybody for responding and helping me out with my beetle problem. My wife and I will be sneaking up on the buggers tomorrow morning with a bowl of soapy water ready to go. Considering the season for the beetle is coming to an end, we will try to go the chemical-less route. Thanks again for all your help, and rhizo_1, thanks for the follow-up.
Kimmsr
11 years ago
Any product, such as Neem Oil, that lists a large number of insects that it controls is a broad spectrum poison and will kill beneficials as well as the pests if not used properly and carefully. Neem Oil products are listed by many toxicologists as broad spectrum poisons.

Here is a link that might be useful: About Neem Oil products
rhizo_1 (North AL) zone 7
11 years ago
Segercasey, that's the right attitude. The JBs seem to disappear overnigbt. Next year, you might wish to be prepared in advance with the neem oil. Don't get the product sold in the health food/natural products stores. The finished product sold for organic pest and disease management is water soluble and comes with detailed instructions.

It's so useful in protecting our food and ornamental plants from certain pests. It's always important to have an accurate identification, though. I hope that you turn to us for help.