Can you use gnatrol on plants with nugs????

So I was just wanted to know if you can use gnatrol on plants that have been in flower for about 3-6 weeks I have a some what bad gnat problem and now wonder if that is my hole problem with the hairs on the buds dieing and leafes surrounding the buds are a light green from the inside out please some one with any thought on this help!!!!

possibly be the problem, could be many others, depending on how light green they are. the hairs dieing is nothing unusuall at this time though. i dont know about 'gnatrol' but 'gnat off' can be used all the way through