You've got a bug lol plain and simple.
The yellowing is possible the onset of a cal, mag, sulfur, iron, or zinc deficiency choose your posion. if it were coming from the bottom up it could only be nitrogen or magnesium but from the top down its a micro.
I suggest getting a good micro nutrient for the nutrient deficiency
as for the bug if your gonna spray get an organic spray that your able to use on fruits the you would consume. I don't know alot about this area but you don't want toxic chemicals on your plants. You could try putting a fan on it to blow away smaller bugs or get a bright colored plastic bowl and coat it with vasoline and set it on the dirt under the plant. when the light hits it it may attract insects because of its brightness and glistening but this isn't gonna do much for the larva thats already been laid.
look up some infestation posts and weigh all your options, this is a fragile area to be in.