What makes my lilac bush...

[Aquarelle]

look like this?

I need help! I love my lilac bushes, but bne of them didn't bloom this year, I assume because of whatever this is (some kind of bug?). How do I fix it??

 

[Halla74]

Spray with a 50/50 solution of Dr. Bronners natural soap. It is ph 7.0 (neutral) as is tap water.

The bodies of insects are alkaline (ph above 7.0) and upon being sprayed with a ph 7.0 solution, will begin to shrivel like little evil prunes, and then die, without forcing your beloved bush to deal with the strain of processing insecticide material.

Also, have you fertilized lately? I know that a few Miracle grow spikes around my scraggly viburnum bushes made them turn into monstrous giants.

Good luck!!!

 

[teslashock]

That looks like powdery mildew (lilacs are pretty hardy and most bugs don't harm them too much, but they do occasionally become ill with fungus). Anyway, this is not fatal to your plant, but you probably should trim away the affected areas and apply a general purpose fungicide for the next month, about 2 times per week (spray it on the other healthy bushes too for prevention).

Also, make sure you dispose of the trimmings in such a way that any spores on them will not spread to your healthy lilacs. (burn or put them in a sealed trash bin that's far away from your plants)

To prevent it in the future, you can look for early warning signs and trim away the bad parts and apply fungicide.

 

[Aquarelle]

Thanks!! That's really helpful. I'll have to pick up some fungicide and try that.

 

[WoodsWoman]

Prune the bushes for good air flow. If the ground in your area tends to be quite acidic lime will help. Here are some other things to consider:
Eight Reasons Your Lilac Bush Won't Bloom