Need help identifying this critter

Question: I have been invaded by these tiny insects.  They are all over my garage door, brick wall and sidewalk.  They don’t seem to have interest in my xeriscape garden. I’ve been invaded for about 10 days.  I can’t see any specific place they are coming from.  I’ve been spraying with vinegar and Dawn hosing them, sweeping them and crushing them with my foot.  If you can help me or send me in the direction of someone who might, i would greatly appreciate it. Thank you so much, Sue Hurwitz <personal data hidden>

responder: An Ask Extension Expert Replied May 31, 2023, 6:43 PM EDT
response: Hello Sue, These insects are aphids. Many insects will congregate on human structures for warmth.  I assume that there are some evergreen trees nearby? My guess is that these are Giant Conifer Aphids (Cinara sp.). If I am correct, then the reason they are uninterested in your xeriscaping is because their food source is a nearby evergreen tree. However, Cinara sp. usually do not demand control measures. They suck sap from trees, and the damage they do is negligible.  If you decide that they require management, you will need to locate the tree(s) they are infesting. You could then treat the tree(s) in question with an insecticidal soap spray. Alternatively, you could apply a systemic insecticide (e.g. a neonicotinoid). However, I caution against the latter chemical control unless absolutely necessary; systemics can stress the tree(s) and the insecticide can be translocated into the tree's pollen which can be dispersed to many non-target organisms. It is possible that the infested tree is not on your property, in which case you would have consult the property owner about treating.  Let me know if you have further questions. I will be in touch shortly to confirm the identification.

responder: The Question Asker Replied May 31, 2023, 8:04 PM EDT
response: I’m so grateful!  My blue spruce.  Good reason to cut it down!Sent from my iPad On May 31, 2023, at 4:43 PM, Ask Extension <<personal data hidden>> wrote:﻿

responder: The Question Asker Replied May 31, 2023, 8:04 PM EDT
response: Oh, I thank you so much.  I am so very appreciative. I’ve been battling them for two weeks. I thought they might be aphids but couldn’t figure out why they did get on my plants and vegetables.  You are so smart!  How long will they stay around?I have a giant blue spruce about 10 feet away.  I’ve never had the aphids before now.  Why would that be?  How do I know if the tree is infested?  Do tree companies provide insecticidal soap sprays?  Sorry to have so many questions but I am fascinated by these things.Thank you, thank you, Thank you!Susan Hurwitz<personal data hidden>Sent from my iPad On May 31, 2023, at 4:43 PM, Ask Extension <<personal data hidden>> wrote:﻿

responder: The Question Asker Replied May 31, 2023, 9:24 PM EDT
response: I’m not planning to cut down my blue spruce.   
I did inspect my blue spruce and saw aphids all along the trunk.  I will need to do something about them because they are getting into my garage and easily tracked inside.  If I am going to have this infestation every year for a prolonged time, I may have to think about.  What would your recommendation be?  I must say, I wouldn’t miss the tree but would never remove a tree for that reason.  The former owners planted it as a cute little tree and now it is huge and right in front of my bay window.  Not great!
Your advice would be greatly appreciated.
Thank you.
Susan Hurwitz <personal data hidden>.




Sent from my iPad

responder: An Ask Extension Expert Replied June 01, 2023, 11:19 AM EDT
response: Hi Susan, Glad I could be of service, and that you could confirm their presence on a nearby tree. I can't speak to seasonal fluctuations in their populations, or why you're just now noticing them. It's possible that they colonized your tree during this spring, or perhaps they were already there but had not made their presence known. It's also unclear how long they'll be an issue since that depends on a multitude of factors (tree health, winter temperatures, natural enemy populations).  Regarding your question if the tree is infested, I believe you already answered that when you confirmed their presence along the trunk. A tree company would be able to perform an insecticidal soap application, or you could buy your own from a department store/garden center/online. However, foliar applications of any insecticide will be ineffective against trees taller than 10 feet; if you can't cover all the foliage, the aphids will find refuge in the higher branches and keep multiplying. And now that I know it's a blue spruce we're dealing with, insecticidal soap may not be a good idea for another reason; Spruces have a blueish bloom (waxy coating) coating the needles. Oils can remove this bloom, which can leave the tree with a sickly yellow-green color.  Your management options are mainly biological and chemical control. In terms of biological control, there are many predators and parasites that prey on aphids. You can encourage those arthropods in your landscape through "Conservation Biocontrol". Here is a link to more information on that practice.  https://extension.okstate.edu/fact-sheets/conservation-biological-control-for-the-home-landscape.html Alternatively, or in tandem with conservation biocontrol, you could apply a systemic insecticide (e.g. imidacloprid) to your tree. You can consult a tree company or a local arborist on how to go about that. https://www.treesaregood.org/findanarborist I hope that it's only this one spruce that is infested. If there are other infested trees nearby, that will complicate their management. I'm happy to answer additional questions.

responder: The Question Asker Replied June 01, 2023, 4:23 PM EDT
response: ﻿﻿Here is a picture of what I think is the culprit.  As you can see, I have a garden that should attract natural predators.   Hopefully, my last questions;If I don’t treat at all, will this condition persist? Might the aphids eventually leave on their own?Would there eventually be cause to remove the tree?Is imidacloprid  safe?I guess what I’m wanting to know is what you would do?Thank you.  You have been so kind and patient.Appreciatively,SueSent from my iPadOn Jun 1, 2023, at 9:19 AM, Ask Extension <<personal data hidden>> wrote:﻿

responder: The Question Asker Replied June 01, 2023, 4:42 PM EDT
response: I’m not doing well getting my response to you. It looks like what I wrote didn’t go to you. I’ll try again.Here is a picture of the culprit.  As you can see I have a pollinator garden that does attract lots of bees, etc. I do have an arborist from Davey Tree coming to take a look on Friday, June 9.  Hopefully, he can give me my options.A few more questions for you and, hopefully the last;Is Imidacloprid safe for my gardens health?Would there be cause to remove the tree?If this problem was yours, how would you proceed?Thank you for all the time you have given me.  I feel a lot better about the situation than I did a few days ago.Have a great weekend,SueSent from my iPad  On Jun 1, 2023, at 9:19 AM, Ask Extension <<personal data hidden>> wrote:﻿

responder: An Ask Extension Expert Replied June 01, 2023, 6:04 PM EDT
response: Susan, I'm glad I could put you somewhat at ease. Your garden is beautiful, and certainly functions to attract natural enemies. If you do not treat, the aphids may or may not persist. As aforementioned, I cannot speak to their future population dynamics because they depend on many factors with poor predictability.  In my opinion, there is not cause to remove the tree, nor would there be eventually. The impact of the aphids' feeding on the tree is negligible; it would not be weakened to the point of being a falling hazard just from the aphids.  Imidacloprid falls within the neonicotinoid class of insecticides, which have been found to have negative impacts on pollinators. The application to your tree would not pose a risk to your health, but the pollen produced by the tree may be ingested by insects which may experience sub-lethal impacts. Since you asked what I personally would do, I would just tolerate the insects. But I am a life-long entomologist who keeps spiders and roaches as pets, so I'm slightly biased! I am happy to continue answering your questions. Feel free to check back with me after your consultation with the Davey Tree people. I will consult my colleagues on this matter as well.

responder: The Question Asker Replied June 02, 2023, 12:03 PM EDT
response: THIS IS THE FIRST REPLYSent from my iPad On May 31, 2023, at 4:43 PM, Ask Extension <<personal data hidden>> wrote:﻿

responder: The Question Asker Replied June 02, 2023, 12:08 PM EDT
response: Sorry, I was trying to send this to my fellow gardener.Sent from my iPad On Jun 2, 2023, at 10:02 AM, Susan Hurwitz <<personal data hidden>> wrote:﻿THIS IS THE FIRST REPLYSent from my iPadOn May 31, 2023, at 4:43 PM, Ask Extension <<personal data hidden>> wrote:﻿