Possibly butterfly larvae? Hard to tell, what zone are you in? Northern hemisphere or Southern Hemisphere? It's a little late in the season for orange dogs, but if you're in Australia, right now would be the time for them. If they are in fact butterfly larvae they will hatch into caterpillars and start eating the leaves on your citrus trees. One single butterfly larvae can probably eat 25 leaves by itself. Let us know where you are in the world and take a closer photo of the balls and post them here so we can help you better.

Evan

Hi Evan. Thanks for the reply. Im in Australia, Victoria to be exact.

They appear to be only on the very edge of the leaves. 1 on each affected leaf, and only on the newer leaves that have come through in the last few weeks.

Hi John. Is the anything i can put on the plant to stop them in future??

Where I live (the Southernmost range of the Giant Swallowtail, we have a couple of species of birds that particularly like them and their larvae (caterpillars); aside from that a good systemic insecticide like imidacloprid will kill the baby caterpillars when they start to eat the leaves. Bayer Advanced Fruit and Citrus is probably the best product you will find; if it is available in your market; if not, ask a local nurseryman or garden shop how to get imidacloprid (It was invented by Bayer Crop Science; but there are now generic varieties available)

Why not just remove them now? Tweezers should do the trick.

Removing the eggs now goes without saying; but that does nothing to prevent them in the future. To prevent future eggs you need to identify the Giant Swallowtail (google), watch for it, and kill/spray/repel it. It is not the butterfly that causes the damage; it is the caterpillar that hatches from the egg.

Fullblown, now you know the time of year they show up. Keep this in mind for next year and check your trees around this time for eggs and remove them accordingly.

Evan

Thanks for all the info everyone. I just removed them by hand and am keeping an eye it for anymore that appear. Much appreciated.

Just pick them off by hand each year. until the trees are over 8 feet tall and wide it won't that hard or time consuming to do. It will also give you a chance to take a good long look over your trees to closely check its overall health.

Funny you should say that Steve. Found some aphids while taking the eggs off. Time to get some white oil!

One of my "secrets" is that someone looks at every tree every day; his supervisor looks at every tree every week; and I try to look at every tree every month; with that system we don't wake up one day with the discovery that "suddenly" we have a problem.

🙆 I have been seeing them for a while and i didn't know what they were. I thought the tree was producing them🤦 I literally just watched a swallow tail butterfly lay an egg on my orange tree seedling. Its been eggs the whole time