# White Fibrous Stuff on Lilac Bush **URL:** \ **Category:** Factual Questions\ **Created:** [September 18, 2008, 9:47pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215 "2008-09-18T21:47:27Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![SharkB8](https://avatars.discourse-cdn.com/v4/letter/s/977dab/32.png) [@SharkB8](https://boards.straightdope.com/u/SharkB8)\ **Post date:** [September 18, 2008, 9:47pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/1 "2008-09-18T21:47:27Z")
Or at least I _think_ it’s a lilac bush. It was kind of starting to look pretty beat up. Here’s a wide: [http://i456.photobucket.com/albums/qq286/vacilandotv/lilacwide.jpg](http://i456.photobucket.com/albums/qq286/vacilandotv/lilacwide.jpg) And the landscaper trimmed it down a bit. I just noticed some white stuff on the branches. The leaves are kinda dull and soapy looking too, but the branches caught my eye: [![](http://i456.photobucket.com/albums/qq286/vacilandotv/whitestuffwide.jpg) ](http://i456.photobucket.com/albums/qq286/vacilandotv/whitestuffwide.jpg) When I got close to it, it almost looked like fly eggs that were kind of dried up. Upon closer examination, the substance almost looks fibrous: [![](http://i456.photobucket.com/albums/qq286/vacilandotv/whitestuffclose.jpg) ](http://i456.photobucket.com/albums/qq286/vacilandotv/whitestuffclose.jpg) Yeah…that can’t be good… Any ideas? ---
**Author:** ![Lamar\_Mundane](https://avatars.discourse-cdn.com/v4/letter/l/85f322/32.png) [@Lamar\_Mundane](https://boards.straightdope.com/u/Lamar_Mundane)\ **Post date:** [September 18, 2008, 10:00pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/2 "2008-09-18T22:00:21Z")
Hard to tell, but I’d guess [a type of scale](http://en.wikipedia.org/wiki/Scale_insect). Note that the picture is only one variety of scale. It can be white and hard like in your picture. Treatment is effective with a [horticultural oil](http://en.wikipedia.org/wiki/Horticultural_oil). ---
**Author:** ![Monstera\_deliciosa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monstera_deliciosa/32/109_2.png) [@Monstera\_deliciosa](https://boards.straightdope.com/u/Monstera_deliciosa)\ **Post date:** [September 18, 2008, 10:12pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/3 "2008-09-18T22:12:59Z")
The stuff on the close up of the branches does indeed look it could be some type of scale, but the whitening on the leaves looks like powdery mildew to me. > **[Site | Ohioline](https://ohioline.osu.edu/search/site/hyg%20fact%203000%203047)** ---
**Author:** ![Chessic\_Sense](https://avatars.discourse-cdn.com/v4/letter/c/7c8e57/32.png) [@Chessic\_Sense](https://boards.straightdope.com/u/Chessic_Sense)\ **Post date:** [September 18, 2008, 10:14pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/4 "2008-09-18T22:14:13Z")
What’s “powdery mildew” do? I’ve got it all over my yard. Will it hurt the plants? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 18, 2008, 10:14pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/5 "2008-09-18T22:14:49Z")
Could be wooly aphids ---
**Author:** ![foolsguinea](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foolsguinea/32/14751_2.png) [@foolsguinea](https://boards.straightdope.com/u/foolsguinea)\ **Post date:** [September 18, 2008, 10:32pm UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/6 "2008-09-18T22:32:31Z")
The stuff on the leaves is powdery mildew. It can retard the growth of the bush, but it won’t kill the bush, & besides, it’s late enough in the year you probably need not worry about it. I’ve been ignoring the mildew on my lilac all summer, & I’ve pretty much quit removing mildewed leaves from my apple seedlings as of September. Earlier this year, I was pulling mildewed leaves off the little trees to stop its spread, as I’m to cheap to go get the specific fungicide that kills it. Now, I’m like, eh, diminishing returns for that plan, let winter kill most of it off. (But my trees are in pots & can be quarantined, so that’s easy for me to say.) I don’t know what the crud on the branches is. ---
**Author:** ![Monstera\_deliciosa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monstera_deliciosa/32/109_2.png) [@Monstera\_deliciosa](https://boards.straightdope.com/u/Monstera_deliciosa)\ **Post date:** [September 19, 2008, 12:19am UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/7 "2008-09-19T00:19:07Z")
PM won’t kill an established shrub, but a serious case can ruin annuals and seriously stunt the growth of perennials, even if it doesn’t kill them. It is my understanding that a prolonged period of high humidity paired with dry soil (due to lack of rain, or insuffcient watering) can exacerbate a mildew problem. ---
**Author:** ![SharkB8](https://avatars.discourse-cdn.com/v4/letter/s/977dab/32.png) [@SharkB8](https://boards.straightdope.com/u/SharkB8)\ **Post date:** [September 19, 2008, 12:28am UTC](https://boards.straightdope.com/t/white-fibrous-stuff-on-lilac-bush/464215/8 "2008-09-19T00:28:23Z")
> [@Monstera\_deliciosa](#): > > It is my understanding that a prolonged period of high humidity paired with dry soil (due to lack of rain, or insuffcient watering) can exacerbate a mildew problem. That pretty much describes the last 3 months here in Rhode Island. So I take it these spores can spread to other stuff in the yard? I have a complete brittle and brown thumb, but this house we got last summer was previously owned by an ambitious gardener and I don’t think I’ve killed anything yet. I think I’ve noticed soapy leaves on other plants, but it’s too dark to confirm tonight. There are roses and hydrangeas on either side of this guy. Is this a lilac for sure? I kind of hate the smell of them (I think they’re the cause of a weird sensation in my ENT that makes it feel like my voice is echoing in my head or that I’m hearing under a capsized canoe), but I was most likely at boot camp when it bloomed.