You may be right but I actually think its too much nitrogen as opposed to too little. I can tell this because of the dark green claw curling on the top of the yellowing plant. I had this in my last run two of my plants yellowing looked nearly identical to yours. And even then, looking at the different plants, one might have a little too much N and one looks like it maybe has a little too much, or a little too little i can't quite tell from the pic.
Just my 0.02 again, i could be wrong but i do believe it is actually too much nitrogen
Edit: Just realized this didnt actually answer the OP's question. I suggest you leave the leafs until they are more dead than that to pick them off