I would not cut those leaves back.....we always get a lot of leaves before the tiny heads start. they protect the vegetable from wind, sun and water damage. Do a mix of 1 teasp of liquid hand soap and 1 qt water mix & spray. Those plants mentioned do get bugs inside and underneath. So when it is time to harvest them especially Broccoli, cut just under the flower...florets....on a slant to leave as much stem as possible other plant will start growing on the stems...won't be looking like the original but will give you florets up and down that stem. Also soak those plants outside in a large container of cold water with 1/2 cup of salt just to get the hard black bugs that will surface and rush out of that salt bath. rinse it again in salt water............and then I checked each piece to be sure no critters are there....final rinse in cold water. At the very end those leaves and stems can be washed & cooked. If you don't like to do that and you have chicken....just pull it out and hang it on a rope off the floor and the chickens will eat every drop.