leaf bug

I have a small eucalyptus tree growing in my back yard. It was growing nicely for a couple of years until along came this microscopic bug that appears to lay eggs in the leaves. They start of a blackish spots and eventually the whole leaf is consumed. The same bug eats the new leaves while they are small and tender, they tend to shrivel up at the same time. I left it alone at first because I think it's a native and read that by the time you get around to spraying it the bug will have "move on". However this has not happened and the little tree seems to be losing the battle. I live in a dry, drought prone area and I was wondering whether lack of water contributes to the problem with it being a young tree? I've tried using white oil but not sure whether it has had any effect and whether I should be using it? Any helpful suggestions would appreciated thanks.

 

Yes drought will stress a plant and make it more suseptible to pests and disease. As far as treatment the first step is to identify the insect or disease. Since you said the bug was microscopic it is not visible and black spots on the leaves can be a fungal infection.

 

Thanks Pilot Dane. I do think it's a bug because it's eating the green leaves as well, hopefully you'll see in the attachments. One thing I've noticed recently is some tiny little white eggs? I'd like to spray it but what with?

 

Many insects will eat leaves and many of those are large enough to see with the naked eye. So, it is very possible that the critter eating your leaves is not the one causing the spots on the underside of the leaves. It's possible you have more than one pest or disease.

When I see the long eaten trails I generally think of a type of caterpillar. Extremely small insects tend to pierce the leaf or stem and suck out the juices and are too small to eat large portions of leaf. But, I am in N. America and have no idea what pests you have in Australia. Someone in your area should have a better idea. Try taking some leaves with damage to a local garden center, agricultural extension office or a local feed & fertilizer store.

 

Thanks a lot Pilot Dan for your time and trouble.