eating yellow loosestrife

Asked June 30, 2015, 2:52 PM EDT

I have inch long gray worms eating my yellow loosestrife. They don't seem to be interested in anything else. Checked the internet and someone suggested they might be sawfly larvae. I have sawflies on my hardy hibiscus some years so I know what that looks like--they are shorter than these and flat-ish where these are round and squishy-looking. Can you tell me what these are and how I can kill them this year and prevent them from coming back next year. I have not seen them before in my garden. They seemed to appear over night and turned the loosestrife into skeletons in no time!!

Baltimore County Maryland flowers pest control insect identification loosestrife sawfly larvae

1 Response

Can you attach a clear digital photo to this reply?
It is possible it is a loosestrife sawfly larvae.
Here is a page about the similar hibiscus sawfly:
Monostegia abdominalis is a type which is found on plants in the primrose family, including some loostrife.

They are controlled best by hand picking and dropping them into soapy water.
They can also be sprayed with horticultural oil or spinosad.