After looking under magnification, it appears that you have an unusual but not unheard of problem. IMO you have thrips insects and aphids. Usually one has one or the other but not both. What I would do is spray with Safers Soap. It is very effective against both insects. Also, I believe you will find a product such as Captain Jacks Dead Bug Killer to be MUCH more effective against chewing insects than Sevin and is also much safer. Neem, once the bottle is opened has a limited shelf life and is better at controlling fungi and insect eggs than it is at anything else.