Not sure what's going on with my hot pepper plants... they all seemed to present the same symptom, leaves are curled and deformed. Watering is consistent, I've feed the plants a couple of time with tomato food plant from miracle grow, no aphis and or bugs (at least of what I can see), nevertheless I sprayed the plants with insecticide as a precaution, but nothing changed.

I'm living in a tropical country, its summer and the temperatures are around 100 F. These plants are 3-4 years old so they been fine a couple of summers without any issues.

Any help appreciated.