Crepe Myrtle Troubles

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Crepe Myrtle Troubles

Postby Greenleaves » Thu Feb 12, 2009 2:41 pm

I have 6 Crepe Myrtle trees 2yrs old abt 1 mt high that are suffering terribly from powder mildew.
Will they ever grow out of this or is it something that you have to deal with all summer year in year out?
Last year I threatened to pull them all out - they line a roundabout & I can imagine them looking a picture if healthy.

I'm not tolerent of unhealthy plants...
We're in the Dalby area & it's not that humid here but it must be enough to upset them.
Should I wait until spring & really hit them with something to try & beat it??

The neighbours half a km away have a beautiful mature tree doing so well - why can't mine!

I'd be greatful of any suggestions as to how to overcome my prob trees.
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Re: Crepe Myrtle Troubles

Postby taffyman » Thu Feb 12, 2009 3:08 pm

Greenleaves, are you watering over the leaves? I have three large Crape Myrtle trunks in training as Bonsai and since I've had them, I've noticed that if I water over the leaves I end up with powdery mildew but if I only water the soil I don't. Rather strange really because our humidity here in Maryborough would most likely be more than yours, and I don't get the mildew from rain either.
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Re: Crepe Myrtle Troubles

Postby Greenleaves » Thu Feb 12, 2009 3:27 pm

No Taffy - trees on dripper.
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Re: Crepe Myrtle Troubles

Postby greg.l » Thu Feb 12, 2009 5:15 pm

Sometimes mildew can be caused by drought stress. Are there any large trees nearby causing the soil to dry out quickly?
Sprays such as bayleton can cure mildew to some extent but you would have to check the label to see if it covers crepe myrtle.
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Re: Crepe Myrtle Troubles

Postby Greenleaves » Thu Feb 12, 2009 7:11 pm

No large trees nearby - new garden & it's been watered & regularly & mulched (altho this needs redoing I see).
I remember reading to have the trees that they would have plenty of air flow & I chose the ones that were suppose to be mildew resistant. So what have I done wrong :?

I guess once they become diseased it spreads to all the trees. I shifted one of the trees to a different part of the garden & this one doesn't have it! :roll:

Thanx for sugg.s
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Re: Crepe Myrtle Troubles

Postby taffyman » Thu Feb 12, 2009 9:17 pm

Another solution is given in a book by Tom Wyatt from Rockhampton - and this worked when I had it on mine (before I stopped watering over the leaves).

Mix 2 tablespoons of Copper Oxychloride or Bordeaux and 2 tablespoons of Mancozeb with 6 teaspoons of Neem oil or a wetting agent in 4.5 litres of water.
Spray every seven days until eradicated (I only needed to spray twice and I used Copper Oxy, Mancozeb and a wetting agent).

I think like Greg.l said, mine was started by drought stress. I had only recently dug them out of a garden and there were very few roots on them, so although they put out a lot of leaves they also needed a lot of watering - more than I realized. I haven't had the problem again since the roots have developed.
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Re: Crepe Myrtle Troubles

Postby greg.l » Fri Feb 13, 2009 5:54 am

Copper oxy, mancozeb and bordeaux are preventatives, not curatives. They will protect new leaves but not any already infected. Perhaps the tree that was moved has gone into better soil and got established better. Once the other trees get better established they might be more resistant, or move them all to the other site.
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Re: Crepe Myrtle Troubles

Postby Greenleaves » Fri Feb 13, 2009 10:10 am

The tree that I moved actually is only 1/2 the size as I'd put it in a pot in the greenhouse to give away but ended up planting it out. (no didn't change my mind just wasn't suitable for that person I had in mind & I needed to shift it!) So it hasn't really taken off yet - we have salty water & it takes a bit for anything to settle :P .
The others have alot of branches & I wd say are quite root established.

So those products are preventives. And I will try them. So whats best to use on the already sick bits?
I think hubby had been using menga-zed (going on sound for spelling :oops: ) but it never really did anthing or did'nt keep it up enough perhaps. It was a fungaside used in cropping - which shd have did the trick.

Oh to have some fresh green leaves!

Thanks again for your brain racking!
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Re: Crepe Myrtle Troubles

Postby greg.l » Fri Feb 13, 2009 12:34 pm

From a bit of reading of labels and the internet I would guess that wettable sulphur in spring and bayleton in summer might be the best sprays for crepe myrtle, they are recommended for powdery mildew in apples. copper oxy and mancozebare for downy mildew, not powdery.
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