The leaves have pink to red ball-like sucklings on them, and they don't seem to be insects, maybe fungus. What can I do?
If it's caused by a fungus, then neem oil should help. In addition to being an effective insecticide, it's also a great fungicide. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My gum trees new growth has been infested with eggs and yellowish caterpillars with black heads. I have removed all I can. What can I spray them with to protect them?
I am uncertain of the pest that is attacking your plants, but caterpillars and worms can typically be killed either by using Bt or neem oil. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/insects/prevent-caterpillars.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
I have a young flowering gum tree with new growth that has been attacked by these stinging moths (Doratifera Vulnerans). Is there something I can treat the plant with?
My general goto organic pesticide is called neem oil. It will kill any bugs that chew on the plant but leave any that do not (like bees and ladybugs) alone. It is also systemic, so you only need to spray a small part of the tree to protect the whole tree. Here is more information:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
If tree has signs of die back in some larger branches, with the bark splitting from top down for 10 to 12 feet and limb is about 6" in dia. , can this tree be pruned now? We live in central west NSW.
It is fine to prune this tree now. It may be a fungus affecting the tree, so you may also want to treat it with a fungicide.
I have a "gum ball tree" which hangs over my driveway. No place to park my car because of the falling tree sap. When does the trap sap stop running?
Sap normally only runs in spring. If you are seeing a long term dripping of "sap", it is likely not sap but rather aphids. This article will explain more and will help you treat it:
https://www.gardeningknowhow.com/plant-problems/pests/insects/aphids-tree-disease.htm
Have a gumball tree hanging over my driveway. Cannot park car there because of falling sap. When does gum ball tree sap stop running?
Taken from similar question on another forum: "...is a certified arborist for The Ohio State University- Agricultural Technical Institute (OSU-ATI) and a member of the International Society of Arboriculture , so I posed your question to him. Sweet Gum trees "do not weep sap." However, without seeing your tree, he would have to make an educated guess and say that any type of "sap" that falls onto a car would actually be the result of an insect problem. Aphids leave "honeydew" behind - a clear, sticky mess on leaves and cars. They DO like sweet gum trees!
Here's a good site about aphids:
http://ohioline.osu.edu/hyg-fact/2000/pdf/2031.pdf ..." Hope this helps.
We have young gum trees at the back of our property. We are on rural land and the trees have been in for about six months. Two trees have round lumps about half to full size of a marble. Can you please advise what this is and how to deal with it?
Thank you
Tommy
You don't mention where on the tree these bumps are, which is important. Your description sounds like some kind of gall, or maybe a canker. Galls are usually not terribly dangerous. https://www.gardeningknowhow.com/plant-problems/environmental/treating-leaf-gall-on-plants.htm
although some galls, and most cankers, are caused by infectious agents: https://www.gardeningknowhow.com/plant-problems/disease/how-to-fix-crown-gall.htm
https://www.gardeningknowhow.com/plant-problems/disease/weeping-amber-in-trees.htm
For a good diagnosis you can take some samples to the nearest county extension service, where they can give you treatment advice as well as tips on how to keep your trees as healthy as possible. This link will help you find the nearest office:
https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm