Oh, I think that's what I have on my sunflowers! Thin green, slimy looking cats. WHAT ARE THEY!?? they reminded me of the first instar tobacco worms minus the horn.

They are probably the caterpillars of geometrid moths, of which there are too many to ID. You might be able to ID them if you capture and feed one and are able to note certain distinguishing characteristics when the adult moth emerges. A daunting task!

I've had lots of the darned yellow-striped armyworms on things and I just squish them.

Susan

Interestingly enough, I got a phone call today from someone who SWEARS that these green worms are AMAZING and are eating the aphids on the Milkweed...

I told her to keep an eye on them as I really doubted that this was occurring. She said that she had what she was told was a Ladybug larva but that the larva was now gone and all that is left are these green worms that inch along but the aphids have all been stripped off the Milkweed.

I told her that I was certain the Ladybug larva was responsible for eating the aphids but she insists it is the green worms. I said, "I am sure it is a geometrid moth caterpillar but if you really think they're eating the aphids, keep watching and see what happens to the leaves on your Milkweed!"

there are many types of beetles that eat aphids only in their larval stage. Also many types of flies have aphid-eating maggots that look nothing like the housefly maggots. Both are often worm shaped. Many insects have life stages that can be worm like.

All we have to go on is its worm-shaped. That does not mean that the larva is lepidopteran, although its likely. Any additional information would be helpful.

Could it be a flower fly larvae? They eat aphids.

Does it look like this?
{{gwi:492263}}

No, she said, 'skinny and green worm that moves like an inchworm' which to me, sounds like a geometrid larva. The fact that she just had a ladybug larva THEN the aphids disappeared THEN she noticed the 'worms' is awful suspicious.

Now, does anyone know what fly or other insect may have little black, shiny, hard, spherical eggs that are laid either on top or under Milkweed leaves? We're talking super-tiny eggs here that are hard as a rock and super shiny.

Todancewithwolves, do your Flower Fly larvae become green with coral-pink designs along the center line on the back? Mine are gorgeous. At first I thought they were Harvester caterpillars. Their pupae look a lot like Harvester pupae, too. I wonder if there's a reason for that.