Hi Shirley,

Thank you for your question!

Though it is difficult to say definitively without more close-up photos, this damage could be caused by leek moths. For information on the leek moth, see: https://www.uvm.edu/extension/leek-moth-damage-monitoring-and-detection. There are a few key indicators that you can look for with leek moths:

1. Damage to garlic plants is most noticeable to the scape - It sounds like this is the case with your plants.

2. Damage and evidence of insect activity associated with the garlic leaves is concentrated on the inside the leaf fold - This seems to be the case based on your description.

3. Frass (excrement) and debris are left behind - The small dark spots in the photo as well as the granular white material you described could be frass and debris from feeding on the leaves.

These all make leek moths seem to be a likely candidate. For some other possible look-alikes, see: https://www.uvm.edu/extension/leek-moth-look-alike-damage.

The best ways to control leek moths include putting row cover over garlic and any other allium crops, removing larvae from the plants manually, and removing plant debris at the end of the season to minimize adult overwintering. Long-term, you may want to rotate these crops out with a non-allium plant.

For more information on management, check out the following two resources:

- https://www.uvm.edu/extension/leek-moth-control

- https://www.mofga.org/resources/pest-control/leek-moth/

Thank you again for the question, and hope this helps!

Best,