why do new fruits fall off lime tree?

Question

Lime tree makes lots of flowers, then just as green fruit part develops, it falls off.

Answer 1

This sounds like you have a pollination problem. Something is keeping pollinators from getting to the plant and the fruit falls off because they cannot produce seeds.

These articles will help:
https://www.gardeningknowhow.com/garden-how-to/beneficial/creating-a-pollinator-garden.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/insect-pollination-process.htm