Knowledgebase

Ants in my leaf mould #798593

Asked June 29, 2022, 2:53 PM EDT

I have a lovely pile of composted chopped up oak leaves that I was preparing to use as mulch in my vegetable beds but I see it is populated by a very large quantity of small coppery brown ants who are carefully tending their little white oblong eggs. I assume it’s best NOT to introduce this to my Eugene vegetable garden. Please advise.

Lane County Oregon

Expert Response

Dear Erika Leaf:

Generally speaking, dry conditions in a compost pile encourage invasion by ants. I would assume the same is true for leaf mold.

All is not lost, however. You could turn and water the leaf mold a couple of times in the coming weeks. That should start the ants on a concerted effort to remove their eggs to more favorable conditions.

Alternatively, you could apply the leaf mold to the garden. I'm not aware that ants prey on plants - though you'd expect a great number of ants on your arms while you apply the leaf mold. I'd expect the wetter conditions of a vegetable garden to discourage the ants.
Linda J. Brewer, Senior Faculty Research Assistant II Replied July 05, 2022, 12:51 PM EDT
Linda,

Thank you for your thoughts on this.  However the part of the leaf mould that the ants and their eggs are in is actually quite wet.  They did not appear in the dryer upper layers of the leaf pile. 

Can you tell from the photo what kind of ants they are?  What do ants eat or do in a garden?  Do you think they’ll just leave or will they colonize the garden beds in some way that is problematic or helpful??  I also wonder what will happen after their eggs hatch, which perhaps they have by now…. 

Are there any ant experts in the Extension who we could consult?

Thanks so much for your assistance with this inquiry.

Warmly,

Erika Leaf



On Jul 5, 2022, at 9:51 AM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied July 05, 2022, 1:05 PM EDT

McKenzie:

 

I asked at the time that those additional questions came in that it be forwarded to an entomologist.

I’m not the ants expert …

 

Linda J. Brewer, Senior Faculty Research Assistant II

Oregon State University | Department of Horticulture

 

 

 

From: askextension=<personal data hidden> <askextension=<personal data hidden>> On Behalf Of Ask Extension
Sent: Wednesday, July 13, 2022 9:26 AM
To: Brewer, Linda J <<personal data hidden>>
Subject: New Internal Activity Alert

 

[This email originated from outside of OSU. Use caution with links and attachments.]

Linda J. Brewer, Senior Faculty Research Assistant II Replied July 13, 2022, 1:00 PM EDT

Great, welcome McKenzie.

 

When questions contain the words, soil, compost, soil amendments, manure, etc. – I’m your person.

 

Carry on! You’ll catch up sooner or later.

 

Linda J. Brewer, Senior Faculty Research Assistant II

Oregon State University | Department of Horticulture

 

 

 

From: askextension=<personal data hidden> <askextension=<personal data hidden>> On Behalf Of Ask Extension
Sent: Wednesday, July 13, 2022 10:00 AM
To: Brewer, Linda J <<personal data hidden>>
Subject: New Internal Activity Alert

 

[This email originated from outside of OSU. Use caution with links and attachments.]

Linda J. Brewer, Senior Faculty Research Assistant II Replied July 13, 2022, 1:05 PM EDT
Linda,

Are you sure you forwarded the right thing?  This doesn’t make sense…

Erika


On Jul 13, 2022, at 10:05 AM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied July 13, 2022, 1:10 PM EDT

Apologies Erika,

We are working on connecting you with someone who is suited to answer your follow-up questions. Linda meant to reply to just me, but accidentally included you as well.

I'll be assigning your question to someone else.

Take care,

McKenzie

Take care, Replied July 13, 2022, 1:23 PM EDT
Hello,
The pictures don't show enough detail for me to be certain about an identification. However, it's likely a colony of moisture ants (in the genus Lasius). They will nest in decaying plant material so having them nesting in rotting oak leaves seems possible and resemble the ones in your photos. The best way to have an sound identification is to take specimens to your local extension office or at least send in some clear closeup pictures. Then we can provide some appropriate management recommendations. 
An Ask Extension Expert Replied July 21, 2022, 11:17 PM EDT

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