wont the cosmos be dead to the ground in a week or 3??... if so.. what the use of fighting them now???

its that time of year.. where i might just cut them all down and be done with them ... rather than waste time and money on treating for them ...

wouldnt be surprised if they wouldnt feed the birds.. but half of the birds already left ... lol ... it appears everyone thinks its mid fall... and only going to get colder ...

ken

You're absolutely right. The cosmos have a few more weeks before they die but I grow cosmos every year and would like to be prepared for deal with whatever this caterpillar is, next year.

I would like to not waste money buying more cosmos seeds if they are going to annihilated, early next summer, by this little creature:).

It may be a yellow striped armyworm. Bt will work on it.

tj

Thank you zen_man for identifying it. I hadn't had this problem until this year. I'm quite ok with a bit of manual removal and squishing:). Thanks again.

tsugajunkie thank you for the Bt suggestion. Looked it up it's easily available on Amazon. Armed for next year:). Thanks again.

In lieu of squishing, you can fling these critters into the grass so it can be a bird meal.

It does look like an armyworm, the offspring of a ubiquitous, nondescript moth. Probably not a guest you would prefer to have in your garden, but it's normal for occasional critters to do occasional things to plants, and a little munching is normal and won't hurt anything in the overall picture. And also normal for you to remove them if there are enough to damage your enjoyment of your plants. Since it will fly away as an adult to lay eggs who-knows-where, it's not something that requires some kind of action to deter for next year.

But on the general subject of caterpillars and blooming plants... Hopefully you are among most people who appreciate pretty butterflies... which come from caterpillars. Some garden plants are host plants (food plants) for the caterpillars of various butterflies. I usually try to ID a caterpillar before doing anything to it because it would be cruel and unusual to attract beautiful butterflies to my garden, where they laid eggs, and then destroy their offspring, their caterpillars.

Yea, definitely identify it first before nuking it. Better yet, just toss it onto the grass or ground and give a bird a free meal.

Tiffany and mxk3, I heartily agree:). Normally I'm so excited when I see caterpillars munching on host plants. This year I had quite a lot of swallowtail/monarch caterpillars gorging on ammi majus in my garden and it was a joy to watch (watch video). The ammi survived and thrived afterwards.

This particular caterpillar, if it was the cause, literally seemed to drain the life out of the plant to the point of it drying out and losing all its flower buds and eventually dying.

I had never witnessed that in previous years, which is why I took so long to post and ask. I kept waiting to see if the plant would recover but it just got pitifully worse and died. This was a 5 foot plant that was flowering healthily.

Perhaps there was something else going on but on each occasion, I kept seeing one or two of this caterpillar and could not identify any other problem.

Hoping for a more fruitful year next year for both the plants and creatures in the garden:).

FWIW, I don't usually bother to pull them off, but just squish them between my fingers. Gloves help.

Tsugajunkie identified it correctly as a Yellow Striped Armyworm. They have many plant species that they will use as hostplants, so you can just pick the caterpillars off and toss them in a weed patch, and they'll probably survive. Caterpillars make up a large part of what birds feed their young, and we've already lost 1/3 of all our bird species due to habitat loss and fewer insects.