Magnolia Attacks

We have many magnolia plants in the garden and over the past few weeks two of them have been being eaten/attacked. The only difference we can point out is that the two magnolias that have been being attacked/eaten have feathery/textured/veiny leaves and the rest of our magnolias have a sort of waxy more solid texture to them. We haven't spotted any snail/slug trails and pellets dont seem to be working, we can't see any ayphids or other obvious pests. We suspect it could be ants but again we can not spot any and there are no nearby nests and there are no flowers currently on either plants as one of the magnolias has only flowered once and the other has never flowered. The leaves turn brown once bitten/attacked and rot and drop off and seem to be eaten cleanly from the inside. If you require a photos/photos please tell me and i will do my best to get them to you. But please help we do not wish to lose this magnificent plants. I am writing on behalf of my dad.
Tamara

 

Good evening Tamara and welcome to the site. If the leaves are being eaten from the inside then it sounds like Leafminer. Spray with a systemic insecticide. Ideally though, we need some pics to be certain.:gnthb:

 

i'll get you some pictures first thing in the morning =] and upload them straight away =]
thank you for the quick response =]
Tamara =D

 

We really need your photos in order to make a more educated diagnosis.
However I'd say that ant damage is unlikely as ants tend to go for sweet things and if you've spotted ants on the trees it's most likely that they are going after greenfly or the honeydew excreted by the greenfly.