A man is truly ethical only when he obeys the compulsion to help all life which he is able to assist, and shrinks from injuring anything that lives. If I save an insect from a puddle, life has devoted itself to life, and the division of life against itself has ended. Here the scale can be small, and the meaning sacred. But when extremely large numbers are involved, this is what I label genocide. The fact that they are mostly insects is irrelevant.
Insects are animals, just as much as humans are.
And even if he were killing plants, it would still be genocide. That a species is a mere insect does not in any way diminish from its importance to Gaia, and therefore to us. But what about household pests, you ask. The same issue of Sierra has an article called Reining Cats and Dogs that tells how to control pet fleas naturally. As for people who use insecticides on themselves, I hope and pray that the article Cancer, Inc. on page 36 never applies to them.