Thanks for your question.  This is a bacterium that is toxic to a whole variety of organisms.  The optimum time to apply these bacteria will depend upon the organism to be controlled.  For this reason I cannot give an exact answer to your question.  What specifically are you trying to control with Bacillus Thuringiensis?

Looking forward to you getting back to us.

The pic I sent was for question #0104547

Thanks for getting back to us.

I pretty much suspected that you were going to use Bacillus Thuringiensis (BT) on Japanese beetle grubs but just want to confirm your intentions. As you may know BT is a naturally occurring bacterium in the soil that produces toxins to a variety of insects, including Japanese beetle grubs. These toxins enter the digestive tract of the grubs and leads to the death of the grub. Most research indicates that BT is effective whenever grubs are present in the soil. Adult beetles will probably start to appear between now and the end of June (2023). Soon thereafter the adults will mate and lay eggs. These eggs will quickly hatch to produce grubs. This will occur in early July. You should make at least two BT applications separated by a couple of weeks during July. A third application before mid-August would be best. Different BT products may have different application procedures. Be sure to carefully read the directions on the label. For further information see:

https://www.vandermeernursery.com/controlling-grubs-in-your-lawn/

https://extension.umd.edu/resource/white-grub-management-lawns

https://gardenerspath.com/how-to/organic/bacillus-thuringiensis/

Good luck. Please get back to us with any further questions and/or clarifications