noobthumb - Hi - I hate to say this, but "welcome to the ant-capital of the world - zone 10 to be exact." Most likely, they are Argentine types, but there are several kinds to deal with. Some seem to prefer sweet stuff. Later in this season, they are attracted to protein-like dead flies you swatted in the living room, for example. In most old houses, they are thoroughly entrenched in and around the foundation - making easy access to the house - depending upon the weather. They, however, don't seem to bother tree roots, but do carry aphis - to suck juices from the tree leaves, which they "milk" and carry to their burrows. My main method of attack, is to spray around the foundation of the house sparingly, but unless you want to live in a constant cloud of insecticide spray, it is best to try to live with them. Some bleach cleansers may help discourage them inside, and a mixture of honey and boric acid in a butter container outside, may be of some use. (ratio of 9 tsp honey/1 tsp boric acid). This may be helpful at base of trees. The butter container has holes made about an inch from bottom to fascilitate entry. About peach trees in zone 10. I planted 2 already - one is a Bonanza dwarf - low chill, the other is a Florida Prince. The Bonanza had quite a few nice fruit - close to Elberta taste-wise, the Prince is just now leafing out. I'm thinking it hasn't been too happy with our cold wet winter/spring so far. Sorry about those ants - wish they didn't like it here - but with our mild winters, they just don't have a lot to keep their numbers in check. Bejay

Are they living in a hollow? If so, they're just living there, not eating the tree. Another reason for ants is that they are "farming" insects for honeydew -- that sticky stuff that aphids, some scale and mealybugs excrete.

The only problem with ants is that you must keep a sharp lookout for aphids. Some varieties of ants farm aphids and they will bring them in and place the aphids on your plants. Not all types of ants do that. I've had ants pretty consistently go after ripe fruit on the trees. I simply spray a narrow band of insecticide on the base of the trunk, and that stops the problem without spraying near the fruit. I guess that wouldn't work so well on berries, since there is no trunk. I leave the ants alone unless they are biters or think they'd like to move into my house.

Wow, I've never seen red ants on a fruit tree before, and we have lots of fruit trees. Normally, if ants are on a fruit tree, that generally is a sign that the fruit tree has some other problem---normally aphids (the ants are attracted to the honeydew the aphids produce) or scale insects. So the first thing I'd try would be to carefully check the trees (look on the undersides of leaves for aphids) to see if I can see something else that is attracting the ants. Then, I'd address whatever I found. Also, look at the place where the ants are feeding and see if there is a sticky substance there (that likely would be the honeydew from aphids). If there is, you might try to wash it off. The best products I have found for ants are organic products that contain either Spinosad or Avermectin in them as their active ingredient. The ones I use are in baits that the ants ingest, and I use two different ones. I use an ant control bait containing Spinosad (the one I generally use is called Come and Get It, but I've used a different one by EcoSense too) for fire ants that get into the raised beds in my fenced-in veggie garden plot. Then, for the carpenter ants that devour wood, I use a product called Advance that contains Avermectin/Abamectin. You'd have to check the labels to see if they can be used around fruit trees. I've never had to use them that way, and don't remember what their label may or may not say about it. If they can be used around fruit trees, you could scatter the bait product on the top of the soil around the trees. Another solution would be to first use a sharp stream of water from the hose to knock all the ants off the trees. Then, immediately after that before they can climb back up into the tree, apply Tree Tanglefoot to the trunk of the tree. They'll get stuck in it (hopefully) and that will be the end of them. You can sometimes find Tree Tanglefoot in nurseries or garden centers, or can order it online. I'll link some so you'll at least know what the packaging looks like: Tree Tanglefoot Instead of Tree Tanglefoot, some people attempt to get the same effect by wrapping duct tape around the tree trunk with the sticky side out in the hope that the ants will stick to the duct tape. I don't know how reliable this method will or will not be. Sometimes you can address fruit tree pest problems by spraying the tree with a summerweight, superfine oil (a lighterweight equivalent of the heavier dormant oil). Do your research carefully on the temperatures at which summerweight oil can be applied, because even though the company says it can be applied in "hot weather", I am not sure I know what their definition of hot is. Sometimes in gardening discussions, companies say something can be used in hot weather, but they don't really mean it can be used in our kind of hot weather. Spraying the tree with an insectical soap following label directions might work. You also might have luck spraying the ground around the trees, and maybe the outside of the containers the trees are in, with a peppermint soap/water spray. Ants follow a scent trail left by other ants and the peppermint spray interferes with their ability to smell the scent trail and follow it. Unfortunately, this only works until rainfall or irrigation washes away or further dilutes the soap spray, so it is not a long-term solution. The brand of peppermint soap I use is Dr. Bronner's. Be careful to not apply too much soap. I use 1 tablespoon per 1 quart of water. Soap is not only a good pesticide in some cases, but it also is a herbicide at higher ratios of soap to water. Good luck with your ant problem. Dawn