Q.Avogado tree leaves fall out
My avocado tree leaves become dry and crunchy while young plants leaves fall out but tips are green and seems to be in good shape
What could be the reason
Thanks for your reply

Unfortunately, this could happen for very many reasons. This can happen for just about any kind of stress to the tree, including pests, over and under-watering, too much ultraviolet light, and many more. Here is an article that will give you a better idea of what you are dealing with: https://www.gardeningknowhow.com/edible/fruits/avocado/avocado-pests-and-diseases.htm