Hi African Lady, there are so many possible causes for leaf drop in all trees that its not possible to give you any specific useful answers based on the information you have provided. Generally unseasonal leaf drop is a response to stress by the tree, the stress can be caused by biotic agents; fungi, bacteria insects etc.. or abiotic agents; drought, flooding, frost, chemical injury, physical injury etc...
Olive trees replace their leaves every 2/3yrs and usually is accompanied by new growth in the spring. Trees as young as yours should be able to cope with sudden leaf drop once or twice but the real issue is to identify the cause of the lost foliage. I'm afraid more information is required for any of us to give you useful advice; what region are you in, what is the soil type and conditions....sandy/clay/chalk....wet/waterlogged/dry...sloping/low spot/raised bed etc Any changed conditions that you are aware of in the last 6/12 months around the root system and canopy of the tree; excessive temp variations/high winds/heavy rain/prolonged drought etc... If you can take some photos these will help greatly in geting to the bottom of the problem, olives do have a range of pests and disorders that can trouble them. If you can't post any pics take a very close look at the leaves themselves and describe the colour, shape and texture; yellowing/spots/blotches/pattern of yellowing/signs of insect pests.
__________________ Sean  Trees are poems that earth writes upon the sky,
We fell them down and turn them into paper,
That we may record our emptiness.
- Kahlil Gibran
|