Rule 1 is no spraying until you can actually see what it is needs spraying; that is the only way you know whether what you are using for spray is appropriate, otherwise it is a waste of time and resources. There is a little chewing at leaf edges but it is not serious enough to warrant action.
Mostly what you are seeing is nutrition issues. Citrus plants enjoy soil that is on the acid side and is free draining to ensure the roots can breathe. When an acid loving plant is growing against a wall presumably with a concrete foundation eventually the roots hit the wall where they find lime which is alkaline/basic and the roots have problems functioning correctly. If the location gets wet and stays wet then the roots may have penetrated to the soil water table in which case the whole tree will continue to suffer until it is raised up or the drainage issue solved.
It can help to place a galvanized metal sheet against the wall foundation to prevent roots contacting the lime in the wall and receiving lime from the mortar washed off onto the roots, and even better plant away from the wall into a raised location to ensure good drainage.