I am still confused about caterpillars, and especially cutworms. My extension horticulturist told me I have cutworms and showed me the type damage they incur. The timing of using nematodes for control doesn't always work, so I don't know what to do. They can demolish plants and render them unsellable. What to do?
Cutworms are Lepidoptera. One would think it should be toxic to them. I would suspect difficulty in actually applying the Bt to the place cutworms feed on. That's a good question. I assume you have not found Bt in any recommendations on cutworms. I'd hope that extension person can refer you to an entomologist for a specific question. I would pursue this for you but at the moment have family business and time is very limited.
I found this article today which says that YES, Btk can be used to control cutworms and arnyworms http://www.ipm.ucdavis.edu/PMG/r785300611.html
Edited--Note this "Bacillus thuringiensis subsp. kurstaki (Bt) is not as effective against cutworms and armyworms as for sod webworms and should only be used during the first and second instars. "
Edited because I went back later and read the whole page.
Thanks for a good question.
I appreciate your feedback and research. Very helpful! I forgot that I posted my question until I looked at my info today. The worms are out now, so the timing was good to find your response. I think good cultural practices can be just about as helpful as anything.
Hi, Sally. Thanks for this very timely and informative article on Bt. We have discovered bag worms on one of our recently planted arborvitaes and we bought some to use on them. However, I was concerned about the use of insecticides until I read your article and saw that it's a safe one to use.