Avocado Leave problem
Old avocado leaves turning brown and crispy, younger leaves getting eaten leaving holes in leaves. Hass Avocado planted April 2016 in a large pot under verandah facing north east. Do not over water, this is the second time this has happened. Please attached photos.
The holes in the leaves could be caused by caterpillars, snails, or other pests. The best control method is usually to check the plant frequently and remove and kill any pests you see feeding on it.
The brown, crispy leaf edges are probably unrelated to the holes- they are usually related to either underwatering/ poor root system or to salt or fertilizer buildup in the soil. Please see this article for possible causes:
Also, make sure you are not weakening your tree by staking it. While trees may need staking under specific conditions, this should always be temporary (less than a year) and the tree should be able to sway with the wind, which strengthens the trunk over time: