What makes my lilac bush....

[Charlotte Rowan]

...look like this??



And what do I do about it? I love my lilac bushes, but the smallest one didn't bloom this summer, I think because of whatever this is (I assume some kind of bug). I don't want them to die.

[Trillium]

Looks more like some sort of disease than a bug.  My parents use a soapy water mixture in a spray bottle to get rid of most of those sorts of problems.  That would be my first step!

[Auryn]

Thats not a bug
its disease/chemical.

I will look in my mom's gardening books for you.
I think its what they call "rust"
is it just on the leaves or also on the stems??

[Noble Dreg]

Likely "powdery mildew".

It's been extremely wet and humid as of late.


Mildew: Mildew is caused by a fungus called Microsphaera alni. It appears in the later part of the summer and leaves a white powder on the leaves. Spores are most active when the weather is hot and humid.

You can use a wettable sulfate powder such as Remedy Fungicide to control it naturally. You can can also minimize problems with the disease by providing plenty of room around the lilac for good air circulation. In the fall, clean up and dispose of infected leaves. To prevent spreading disease, do not put the leaves in a compost pile that will be used for the garden.



A link...

http://plantclinic.cornell.edu/FactSheets/powdery/powdery.htm

Found a picture of it on a lilac bush...

http://uconnladybug.files.wordpress.com/2009/06/img_08291.jpg

[Charlotte Rowan]

Thanks, Dreg, that looks like it. Will do!!