Answer:
Citrus greening disease
Step-by-step explanation:
The symptoms sound like citrus greening disease. This disease is characterised by yellowing of the veins in the leaves, splotchy mottling of the entire leaf, leaves that fall off too early, and fruit that can turn green and tastes bitter.
Citrus greening disease is caused by a bacteria, and transferred by insects such as the Diaphorina citri.