Nice I figured great white would have been discussed. I try and feed it every time I transplant and then going from flower to veg and maybe once more in heavy bloom. You shouldn’t have to feed it very often if the microbes have enough nutrients to survive.
The rust color leaves I would just defoliate and let the rest of the plant focus on the new foliage.
So for applying diatomaceous earth. You are mainly supposed to just make rings and boundaries around the base of your plants and maybe sprinkle some up the stem up the plant. A flower sifter works really great for spreading it and keeping it from clumping up. But I personally just cover the whole plants and all as long as they are in veg. No preflower nothing. But it’s meant to just be spread more around the base of the plants. Also it will kill practically any insect so if you do have beneficials you are wanting to keep around don’t spread it onto the plants just focus more on the ground around them. I always trey and do a perimeter around the whole garden or yard area while you are at it.
My thoughts on going into budding is try and knock the bugs back as hard as you can as early as you can going into preflower. Once you get into budding you want to try and stay away from spraying most anything on the plants. If you can get ahead and knock them back enough before budding that’s the best bet but easier said than done. If you do have problems going up into flower. Most of the products you are using can be used up until the day of harvest. What I do to plan before harvest is about one to two weeks before chopping I spray hard one last time and a couple days after spraying I will just wash the whole plant off with water. You can also have a 5 gallon bucket full of water when you are chopping of to the side to dunk all of your branches and wash them off as you chop.
Happy growing!