Hi, I started growing milkweed 3 or 4 years ago and have dealt with orange aphids, tussock moths, but alas no Monarchs (yet??) When I saw the larvae/caterpillars on this leaf this AM I thought, eradicate, must eradicate (I was squishing orange aphids at the time). I stopped myself, hopeful, maybe, just maybe these are Monarchs. Well, none of the popular "web images" of monarchs look like this -- and nor do Tussock Moth images. One TM image did seem to have these black-headed crawlers amongst the fuzzy tufted TMs, But I can't be sure. Thought maybe they could be leaf-miners, so far no damage though. So, anybody, are these very very young TM larvae or, dare I hope, Monarchs or .... thanks. If they are TM larvae should I 100% eradicate? or let a small percentage continue?
Well, what do they look like now? There is a possibility they are young monarchs from what I can find: young monarch larvae - Google Search
ohh ho ho. Glad I didn't abuse them. Been over 24 hrs. They're still massed on that leaf -- and I found a couple of other leaves, same plant, with masses on them too. All the masses, today seem "darker" (like the white of the bodies is changing). They struck me as dead-looking. I nudged a few and they move, but, seems to me, sluggishly. I also found on another plant a much smaller, (maybe 20 individuals) livelier, bunch -- which appeared to have just finished devouring a leaf. They were in the crotch of the stem and main vein. Those guys seemed "furrier" -- and the fur seemed to be taking on the characteristics location/lengths for a Tussock moth cater. I'll check again in the morning. Maybe I'll take a flashlight out there right now...