Powdery Mildew on Juniper

[Emrys]

Have any of you had Powdery Mildew on your Junipers? Does the attached photo look like Powdery Mildew to any of you? If so can you recommend a good treatment from your experience?

 

[Poink88]

Looks like hard water deposit to me.

 

[Emrys]

Looks like hard water deposit to me.

Maybe. But NYC water is some of the "softest" in the country thus the good pizza and bagels. I haven had this tree very long and it did come from LA where the water is quite "hard".However I presume this specific grower filters his water with the utmost care. The white powder comes off the foliage quite easily if gently rubbed and only persists on a portion of the tree, mostly on the lower branches.

 

[Poink88]

You'll be surprised what water (or soil) some growers use.

I still believe it is calcium deposit. Maybe the lower branches, being older, have thicker buildup. If you check closely, all the new growth are really nice clean green. It is neat actually to see where the new growth are coming out.

 

[Beng]

Is that the one you got at Gary's? If so he does not filter calcium from his water. In fact sometimes his older trees have white trunks which wears off with time or it has for me anyway. He only uses a high powered magnet to reionize it I think. It could be calcium. But if its not it could also be a form of beneficial fungus that grows in moister climates like Oregon. I saw a white powdery looking substance on Michaels up in portland and asked about it. The new shoots are extending well it looks like and are a healthy green. That said its always good to give them a few hits with copper and mancozeb now and then if you suspect something? Maybe rotate mancozeb one week and copper one week and then mancozeb again.

 

[Lazylightningny]

I have a persistent problem with white powdery mildew, but it's mostly on my lilacs and Japanese maples. I haven't seen it on any of my junipers.

I still haven't come to grips with it, so I'm getting more aggressive this year- copper and neem sprays.

 

[Emrys]

Is that the one you got at Gary's? If so he does not filter calcium from his water. In fact sometimes his older trees have white trunks which wears off with time or it has for me anyway. He only uses a high powered magnet to reionize it I think. It could be calcium. But if its not it could also be a form of beneficial fungus that grows in moister climates like Oregon. I saw a white powdery looking substance on Michaels up in portland and asked about it. The new shoots are extending well it looks like and are a healthy green. That said its always good to give them a few hits with copper and mancozeb now and then if you suspect something? Maybe rotate mancozeb one week and copper one week and then mancozeb again.

It is from Gary. But I still have a hard time believing it is calcium. I am going to look into this beneficial fungus. It's only on one of the trees I have from Gary.