Good bug bad bug? And why are my poppies dying?

Question

I live in Paris Ontario. My back garden is a combo of raised beds of tomatoes, gladioli,hollyhocks, shasta daisies, peonies, foxglove, bee balm, hostas, onions, chives, strawberries, cotoneaster, cranberry bush, Jacob's Ladder, sedum, and marigolds..

Today I saw a praying mantis in my garden. I also found a black fuzzy caterpillar with a bronze stripe (now dead), leaf hopping bugs, baby slug, and a bright green hair-thin wormlike bug at the base of my rose bush (front garden south facing)...oh yes, and a black frog/toad too.

Q1. Which one(s) are the garden friendly bugs/amphibians - in other words which ones should I be killing on sight?

Q2. Why are my Icelandic poppies dying and now my Oriental poppies are following suit? They're in a south facing garden bed - plenty of mulch, full sun all day. The lower leaves turn yellow, then brown then die off. The blooms aren't affected until the plant is totally dead. They're planted with heuchera, iris, nepetas and pansies.

Answer 1

Definitely keep the praying mantis and the toad as both are predators and feed off other insects.

Get rid of the slugs and green worms (which reminds me of the cabbage looper)

Answer 2

I would leave them alone. The mantis and toad are trying to keep your garden bug free.