It won't hurt them at all. Ant's don't eat leaves BTW. They were probably taking the honeydew from the aphids, which were eating your leaves. You could have just hosed them off.

What Drew said. You did no harm.

All part of the learning process. It was a good idea to wash it off because 10X dosage with some formulations could burn the leaves.

Holes in leaves were not caused by aphids and were probably the work of caterpillars although certain diseases can cause holes as well.

I do not understand how you are involved spraying aphids on growing trees in Kansas in late Dec. This post seems a bit strange. Hmmm. Thought today was Christmas and not April fools.

Merry Christmas everyone- my family sleeps in as I indulge in my favorite forum.

Thanks drew and mark.
Harvestman : I live in Melbourne, Australia

Ah Melbourne the other Kansas City :)

I'm up because the dog needed to go out. He chased something out of the yard? Hopefully it wasn't Santa!

Well I guess the ants could have been going for something else? Although who knows? In Melbourne you may have some way different ants.

Anyway yeah your trees are going to be fine, and you make us feel better because we have ounces and teaspoons and tablespoons, so we often do what you did
too! I guess even if we went metric we can really still mess up too! The pesticide is not systemic so the tree does not absorb it. If the problem persists, left us know. Look for other insects on the trees, although you did probably kill everything currently on the tree, good job!
Keep us updated on the progress of your trees.
What trees did you plant?

I have planted 2plum tree , cherry, mandarin and nectarine.
Also a veggie patch, rose and hibiscus. I did this yesterday eve and tree looks fine so far. I did see a lady bug this morning when I went to check for any damage in the leaves.

Thanks.. U make me feel much better.I have a one month old who keeps me up all night with my tab on side.Can't wait to check on on my tree tomorrow morning.

Ah, I overlooked the metric clue and presumed Kans was Kansas, the U.S. state.

Aphids on the growing tips could slow growth of trees and a weekly application of the malathion would solve the problem. Usually when there are ants on the trees there are aphids, but you should be able to see them, at least with a glass.

Often if you use no poison lady bugs will sort out the aphids after a couple of weeks- at least here. Cherries get aphids here that are harder to control because the leaves curl up and protect them, even from lady bugs.

Also the ants often protect the aphids from predators like lady beetles.

Lady bugs eat aphids, so again pointing to what I said....
Often ants will kill lady bugs to protect the aphids whom provide the ants with food in the form of poop, or honeydew. Which is different from honey do, honey do this, honey do that...
I know I have a honey do list! (grumble grumble).

Aphids are very small and hard to see, look like specks on the leaves. usually on the underside.
The problem with using malathion is it kills lady bugs and bees! Look for them (aphids) in the future, and you can use an insecticidal soap, or just spray them off with a hose, they cannot return. Both techniques do not harm bees or lady bugs. But at times depending on the pest, malathion is called for. Anyway if aphids was the problem, the ants will not return if aphids are dead, no food for them.
The fact you had a lady bug shows you washed the product off, and your leaves will be fine.
Aphids love to eat leaves, in CA on certain trees it looks like it's raining under the tree. So many aphids are feeding, the honeydew is dripping off the tree. Yes, disgusting!

Next time I am planning on herbal or organic spray. Let me know if know anything. I will check for aphids tomorrow. I have snails in my yard for which I am treating but haven't seen any on the side where fruit tree is.

Thanks for the information Drew,

Did have a close look at my trees for aphids . I couldn't see any but saw some dead snails. Could be that. But my nectarine tree have some burnt leaves. Don't know if they were there already or happened today. I did fertilize them last week.may be because of that???

"I did fertilize them last week.may be because of that???"

Yes, it could, you said these are new trees and you never fertilize new trees. So far it looks like your trying your best to kill them with kindness, best let them be!

I just went with instruction by our nursery where I bought this trees. May be I put them close to the trunk. I saw the package and it says 10cm away from trunk. Anyway my bad.. All results of my poor knowledge and carelessness. Hope there is some way to keep them alive.

Citrus may be different. I can only grow citrus indoors here. I have no experience with them. It should not hurt trees. It's worse when you add the fertilizer to the dirt when planting. Some on top afterward is safer. Fertilize next year, or maybe others can give you better advice for citrus. They need to establish themselves. That should take about a year. So it is a critical time. Some root damage may have occured, just keep them moist, not wet, and they should be fine. Lot's can go wrong. Photos of any damage helps us look at it and get a better idea what is going on. You may lose some, and learn from it.
One thing you may want to do is protect the trunk from sun damage. What we do is paint the trunk with interior latex paint diluted about 50%. Do not use exterior.
In the winter with young trees here we can have a problem with field rodents eating the tender young bark at the base of the tree. We use guards or raps to protect the area. Rabbits too sometimes eat this bark. Remove the guards in spring to allow air flow, sometimes insects will live in there too, so they should be removed.