Is it spider mite ?

More water. It's not watered enough. You wont get sweet fruit unless the tree is kept evenly watered.

Nice banana- is that Dwarf Cavendish?

You will usually see webbing on the leaves if spider mites are the problem. It may be thrips. Thrips do cause leaves to roll up. Could you possibly take a close up picture of the dark spots on some of the leaves?

Also, it looks like your tree may have been planted too deep. You should be able to see the top of the original soil line from when it was in a pot. Would you mind posting a picture of the base of your tree as well?

I'm with stanofh, more water. It's also right next to the pavement. Not a great place for a tree to thrive. Helps to hose down the foliage on hot sunny days.

I agree with the others who said it needs more water. I have a small grapefruit tree that has not been in the ground enough years to develop and extensive root system, and the leaves roll up like that when it's thirsty. After I give it a soaking, they seem to flatten out normally. However, overwatering can cause the same problem, and sometimes the leaves curl in very hot weather.