Good morning Joe,

Bt is a great choice for you as a beekeeper for controlling bagworm.  Timing is everything with using this product for these tricky caterpillars, so read your label very carefully.  I am attaching a great factsheet to help you understand the lifecycle and hope it is helpful to you. I don't see a particular question so I am not sure what exactly you need help with.  Are you looking for product?  Have you used it an had poor control?  Double clicking on the link below should lead you to the factsheet.

Bagworm and Its Control | Ohioline (osu.edu)

Make sure to store where there are no wild temperature extremes.  I made that mistake and pretty sure killed off the live bacteria in the product.

If your concerns haven't been addressed, feel free to write again with more detail :-)

Thank you for using the Ask Extension online service!



Hi Again

Yes, there are different strains of Bt that control different pests.  Btk (kurstaki) is what is used for control of caterpillars.  I have attached a couple more links that should help you understand a little better.  Brands names include but are not limited to, Thuricide, Caterpillar Killer, Dipel.  These can be found at garden centers and on Amazon.

The following link is from Buckeye Yard and Garden aka BYGL and you can scroll to the end for details on how this product works.  Again, timing is everything, so pay special attention to that part and also note that the caterpillar has to feed for awhile before they die, so this is not a contact spray-no instant gratification here.

Bagworm "Season" Begins | BYGL (osu.edu)    

This is a quote from another BYGL article (late summer)that you may find interesting, emphasizing the timing aspect again.  These are truly interesting critters: 

"The clock is also rapidly ticking down for standard insecticides to remain effective. Late instar bagworms can detect insecticide toxicants causing them to hasten pupation, but they do not die. However, they do stop feeding which leads to the perception they were killed. Early-pupating females produce fewer eggs, but they still produce enough to continue the infestation next season.

It's important to remember that bagworms may remain attached even if the caterpillars were successfully killed with an insecticide. They look just like bags with live caterpillars. The deception may lead to needless repeat applications, but they can only die once."

I hope this information covers your questions.  Thanks for your follow up quesiton!