Thank you for reaching out to ask2.extension.

There is a lilac blight that is really decimating lilacs.  It’s due to the rain and wet we had earlier in the season.

At this time there is not much you can do.  The treatment needs to be done in the spring before the temps get to warm.. it is a copper based fungicide.

You could cut your bushes down and get rid of the infected branches and all of the debris on the ground.  The blight can overwinter in the stuff on the ground. 

If your bushes are really old, they may struggle through being cut back.  It’s kind of a wait and see thing.  One of mine got this  a couple of years ago and I ended up having to get rid of it after several years.  I did not treat it though, so there may be some relief if you do treat them.

If you want to get more info, google lilac blight and you should find specific brands of chemicals that may help.  I can’t give you that kind of information.

Please follow all label instructions if you do decide to treat.

I’m sorry it was a really tough spring.