1. Flowers (or pre-flowers in the early stage of flowering) are the only way to tell the sex of a plant.

2. Good vegetative nutes have a high "N" value, good flowering nutes have a high "P" value (most fertilizers list their N-P-K numbers on the label).

3. I personally don't have a problem with you using pesticides... as long as you use it in the smallest amount possible. You definitely should stop when flowering starts... preferably a few weeks before, at least.

The thing is, if you clear 2 feet around every plant it might make your plants extremely easy to spot from the air... and it sounds like you have a relatively large grow since you say you have lost 15 plants. Its sort of like having to pick between the lesser of two evils... using poison to kill slugs (and which might kill a few other animals), or increasing your chance of going to jail for an untold number of years. You are the only one who can really make that choice for yourself.

Finally, use periods... sentences, commas, etc. my friend. Please. It makes it easier for people to read and understand what you are saying.