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What's wrong with my Baptisia? #751084

Asked May 20, 2021, 1:53 PM EDT

First there were holes in the base of the leaves, and now there are black spots on the leaves. What should I do? It was planted last July.

Olmsted County Minnesota

Expert Response

Hi,

The hole in the stem may be the indigo stem borer. Look for the caterpillars and you can treat with Bt. The black spots on the leaves are probably from humidity and water on leaves. Water at ground level.

https://www.insectidentification.org/insect-description.php?identification=Indigo-Stem-Borer-Moth

Thank you for your inquiry and good luck! Replied May 24, 2021, 12:44 PM EDT
Thanks. What is Bt?

Is it OK if I just remove the caterpillars?

On Mon, May 24, 2021 at 11:44 AM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied May 24, 2021, 12:57 PM EDT

Sure, you just remove them. Bt (available at garden centers) is a bacteria that is lethal only to caterpillars and does not affect pollinators. http://npic.orst.edu/ingred/bt.html

Thank you for your inquiry and good luck! Replied May 24, 2021, 1:03 PM EDT
Thank you!

On Mon, May 24, 2021 at 12:03 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied May 24, 2021, 3:11 PM EDT

You’re welcome!

Thank you for your inquiry and good luck! Replied May 25, 2021, 2:38 PM EDT

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