Good Morning Anna, 

Thank you for contacting the U of M Extension Service. 

Honeyberry (Haskaps: Lonicera caerulea) are generally pretty tough, but young plants getting established can be more vulnerable to pests and disease. It's impossible to diagnose with certainty from a picture but this would appear likely to be some kind of fungal infection. It's late in the season, so loss of leaves is not likely to have a serious impact on the plant; however, be sure to remove all leaves and debris from the area: do not compost them. Haskaps prefer a more neutral or slightly acidic soil (pH 5-7), so I would suggest a soil test to determine what the pH is and then amend as necessary. Next year make sure there is good air circulation and the site is in full sun.

I am attaching a document from the University of Saskatchewan about honeyberry diseases. 

The summer heat waves and drought has been hard on plants. Ensure it is getting adequate water. 

Good Luck!