Knowledgebase

To squash or not to squash pests? #805914

Asked August 12, 2022, 9:19 AM EDT

Hi! Since I've been identifying more insects in my yard these past summers and have understood how many are non-native or invasive I've wondered are there any general guidance about whether to kill and/or contain certain pests over others? For example, should I kill Asian lady beetles who compete with native lady beetles? Or Mediterranean Katydids that are considered an invasive ag pest in California? Last summer I had a Xenomelanophila miranda metallic wood-boring beetle (associated with wildfires) land on my arm and I just let it go unknowingly. And what about the Emerald Ash Borer? Is there a 'rule-of-thumb' or general practice for these types of "pest control"? I generally live and let live (unless it's slugs or cutworms ;)) but I'd especially like to give the native species in the yard the best chance! Thanks for your help.

Multnomah County Oregon

Expert Response

Hello Audrey,

Thanks for reaching out to OSU Extension Services! I wanted to direct your attention to our list of Emerald Ash Borer resources. Our Forestry faculty has been following this issue closely, and has been making content and answering questions regarding EAB. 

The Forestry experts are all on a retreat right now, so I wanted to make sure you got this information before I assign your question to someone who can answer your pest questions. You'll hear back from someone else.

Hopefully this helps! We are continuing to curate emerald ash borer content as the issue evolves.

Take care,

McKenzie

McKenzie Heryford Replied August 12, 2022, 11:58 AM EDT
Hi Audrey,

Thank you for this great question, which concisely illustrates the conflict that so many of us face, when wanting to conserve insects. Will killing invasive insects do any good?

The rule of thumb biologists use is based upon where an insect might be on the invasion curve. Note that where an insect is at on this curve will differ, from location to location.

If an insect is in phases III or IV of the invasion curve (the orange and red sections of the linked graph), that means that are already well-established in a region, and that efforts to mass eradicate the insect via chemical control or physical removal will likely fail. Instead, management efforts are restricted to minimizing the negative impacts of the insect, where they might do harm. A good example of insects in the phases III or IV of the curve are spotted wing drosophila and brown marmorated stink bug. Both insects are managed on a hyper-local basis, when they cause issues for crops. But, they are so widespread in Oregon, that eradication is highly unlikely. [Note that biological controls are being used against brown marmorated stink bug, in an effort to help manage the pest to tolerable levels.]

Asian ladybug beetles are on phase IV of the invasion curve. They are so widespread in Oregon and the US, that there really is no use in killing them, locally. Doing so will amount to cutting a single hair off of a monster you are trying to kill. It won't make any real difference.

Mediterranean katydids are a phase 1 insect, at least in Oregon. If you see one, I would first capture and freeze the specimen (in case documentation is needed), and then report it to the Oregon Invasive Species hotline (1-866-INVADER or https://www.oregoninvasivespeciescouncil.org/). But honestly, that insect is so widespread in CA, and the harm it causes is ecological and not economic. It is the economically-damaging invaders that tend to get more attention and action from management agencies. Still, if and when it comes to Oregon will be important to document.

Xenomelanophila miranda and Emerald Ash Borer are both on phase II of the invasion curve, where reporting them will be important to helping to stem their establishment in Oregon. Once again, if you're able, I would capture and freeze the specimen, and make a report to the Oregon Invasive Species hotline.

Please let me know if you have additional questions.
Gail Langellotto Replied August 12, 2022, 3:27 PM EDT

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