What to use for relentless attacks on citrus plants in Thailand ?

Bugs seem to love leaves of citrus plants too much.

My pomelo , orange and yellow lemon leafes keep getting eaten.

Sometimes I can catch green 5 cm caterpillars , sometimes 1 cm black ones,

often I can't see who's eating them , usually at night.

What can I use here in Thailand that is not to toxic to spray on the leafes ?

I don't want it in the sand or get on pet's fur.

My Java apple plants get damaged by locusts but haven't seen them on

the citrus plants.