Jun 28, 2012 – Ants – Necessarily A Problem?

QUESTION:

How would you treat 2 specimen Live Oak trees @ 50 ft high each for carpenter ants in the upper branches? A tree surgeon noticed them when in a bucket truck as he was removing the branches that had been weakened due to the damage. This client has this done yearly and is extremely proactive in making sure her trees are well maintained. After this discovery was made and those areas removed the tree surgeon suggested further treatment in the areas where he saw heavy activity. She offered the service of the bucket truck while requesting a treatment. Is baiting sufficient? How would you approach this job?

ANSWER:

For now I would suggest finding out more about this situation, including whether or not there even were carpenter ants. Not to doubt his knowledge, but a tree surgeon is not necessarily a trained pest control person, and the ants that he saw may not have been carpenter ants. Better would be to start with getting some specimens, if it has not already been done, and making that positive ID. 

Second question is whether or not these ants, assuming they are carpenter ants, are doing anything other than foraging for food up in that tree. Carpenter ants do feed on honeydew and other insects, and it would seem to be more likely to me that they would be that high up in an oak tree to gather honeydew from scale insects, whiteflies, aphids, or some other plant-sucking insect, or to gather the insects themselves for food. You say that the tree surgeon was removing branches that were weakened due to "the damage", but are you saying that these ants were actually living within those branches? If so, it seems possible that the branches were already dead and the ants were just taking advantage of some rotten wood within them to create a satellite nest. Removing the dead wood should by itself discourage the ants from continuing to work there. 

If there is rot in the trunk of the tree carpenter ants may move into it to hollow it out further for a nest, and from there may extend their work into sound wood. But, at the top of a large tree it seems less likely that they will find these conditions or work to make that satellite nest. Most often a primary colony is going to be in the soil somewhere in some kind of old wood, such as old dead root systems, buried trees or lumber, and the above-ground nests are satellite nests from this primary colony. As the larvae mature and are ready to pupate the workers seek drier conditions for them, and often create galleries above soil level for this. This is why they bother to enter structures, since they are not eating the wood but only using it as a convenient place to stay awhile. 

In theory, the ants in above-ground nests will still be moving back and forth to the parent colony, so it could be possible to find their trails (look at night, they are nocturnal) and treat them. You also can use granular baits along those trails as carpenter ants seem to take these baits readily. If you can find trails on the ground you might be able to follow them back to where a parent colony is located and treat the colony directly. But, it would still be important to find out if these ants are really any threat at all to these trees or if they are only climbing in the trees for food, in which case you may be able to eliminate those other insects and take away the reason the ants are there too. 


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