Oak tree and powdery mildew

We have some unique pests to deal with in Australia. Post your experiences and treatments here for others to learn from.
Post Reply
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Oak tree and powdery mildew

Post by Mickeyjaytee »

So a long story short, I was given an English oath (I think it’s english) and planted it in the ground. I have another in a pot and the grounded one grew, for the first time 1 single acorn last year which, i planted and that grew 😄

Last year the grounded oak developed powdery mildew on the lower branches. I used some fungicide from bunnings and while the leaves became distorted it seemed ok. This winter the oak didn’t lose all its leaves.

This year it really has taken off with growth and I’m super stoked! The problem is yesterday I noticed the powdery mildew already developing with a vengeance. It’s also just begun on my potted tree yet the sapling is ok.

Is there anything I can do? I did invest in some good fungicide but worry about effects on my pets and general animals/insects.

The oak has sentimental value. It came from a grand old oak next door to my aunties house. People bought the property, knocked down the house with a new one and out in a pool. All was well. Then god forbid, the oak leaves fell into their pool so they cut the whole tree down 😑 luckily saplings had shot up in my aunties backyard which she harvested. These oaks are its off spring so I’d love to do whatever i can!

I’ll upload a pic as soon as the sun is up.

Thank you!
Mickey
User avatar
Sno
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1198
Joined: January 16th, 2011, 12:26 pm
Bonsai Age: 0
Location: Crackenback NSW
Has thanked: 492 times
Been thanked: 614 times
Contact:

Re: Oak tree and powdery mildew

Post by Sno »

Hi Mickeyjaytee . For me the best way to control powdery mildew is a 50/50 ratio of milk and water sprayed onto the tree once or twice a week . Make sure it’s a good coverage . And try to increase the light and airflow around the tree .
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Re: Oak tree and powdery mildew

Post by Mickeyjaytee »

Sno wrote: October 13th, 2022, 6:50 am Hi Mickeyjaytee . For me the best way to control powdery mildew is a 50/50 ratio of milk and water sprayed onto the tree once or twice a week . Make sure it’s a good coverage . And try to increase the light and airflow around the tree .
Thank you so much! That seems very environmentally friendly and I like it! Light is a problem. There is a small tree which was going to be removed once the oak had over taken it. I had left the small tree for shade in summer for the driveway and privacy. Last year we had 3 days in a row of 44 degrees. Brutal stuff. Perhaps remove/cut back the small tree now?

Thank you so much!
Mickey
User avatar
TimS
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1951
Joined: March 17th, 2017, 2:46 pm
Favorite Species: Japanese Maple
Bonsai Age: 9
Bonsai Club: Waverly Bonsai Group
Location: Melbourne
Has thanked: 428 times
Been thanked: 538 times

Re: Oak tree and powdery mildew

Post by TimS »

Alternatively we use parafinic oil at a rate of 1 part to 100 water at work with instantaneous effect, though some plants can be sensitive to it but those are generally softer foliage plants like herbs.

Still a better option environmentally/ personal health wise than many of the fungicides.
KIRKY
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1969
Joined: May 21st, 2009, 3:42 pm
Favorite Species: Flowering
Bonsai Age: 12
Bonsai Club: BSV
Location: Melbourne
Has thanked: 1167 times
Been thanked: 246 times

Re: Oak tree and powdery mildew

Post by KIRKY »

The 50/50 milk works but you have to remember 1. Full cream milk not a low cal skinny etc and 2. If it rains shortly after application re apply, also spray the soil around the tree. I would cut back or remove the other tree. Oaks like an open sunny area, with good air flow around it.
Cheers
Kirky
Great oaks from little acorns grow.
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Re: Oak tree and powdery mildew

Post by Mickeyjaytee »

Thank you all so very much! Extra milk is on the shopping list 😝

Just curious, how long until it will be effective and I can stop applying?

EDIT: just to make sure it is powdery mildew, here are some pics of the beginning which spreads over the leaf
You do not have the required permissions to view the files attached to this post.
Mickey
KIRKY
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1969
Joined: May 21st, 2009, 3:42 pm
Favorite Species: Flowering
Bonsai Age: 12
Bonsai Club: BSV
Location: Melbourne
Has thanked: 1167 times
Been thanked: 246 times

Re: Oak tree and powdery mildew

Post by KIRKY »

How long is a piece of string…. :whistle: pending weather conditions, how good a coverage you give it, if you move or change it’s surroundings more light/sun, don’t water the foliage etc…
Milk full cream: Mix 1 part milk to 1 part water sprayed liberally. Once a week for 3 to 4 weeks, if it rains re apply addition spray and see what happens.
Cheers
Kirky
Great oaks from little acorns grow.
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Re: Oak tree and powdery mildew

Post by Mickeyjaytee »

KIRKY wrote: October 13th, 2022, 9:15 am How long is a piece of string…. :whistle: pending weather conditions, how good a coverage you give it, if you move or change it’s surroundings more light/sun, don’t water the foliage etc…
Milk full cream: Mix 1 part milk to 1 part water sprayed liberally. Once a week for 3 to 4 weeks, if it rains re apply addition spray and see what happens.
Cheers
Kirky
Thanks mate. I greatly appreciate it 👍🏼
Mickey
User avatar
TimS
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1951
Joined: March 17th, 2017, 2:46 pm
Favorite Species: Japanese Maple
Bonsai Age: 9
Bonsai Club: Waverly Bonsai Group
Location: Melbourne
Has thanked: 428 times
Been thanked: 538 times

Re: Oak tree and powdery mildew

Post by TimS »

KIRKY wrote: October 13th, 2022, 9:15 am How long is a piece of string….
Twice the distance from the middle to one end ;)
KIRKY
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1969
Joined: May 21st, 2009, 3:42 pm
Favorite Species: Flowering
Bonsai Age: 12
Bonsai Club: BSV
Location: Melbourne
Has thanked: 1167 times
Been thanked: 246 times

Re: Oak tree and powdery mildew

Post by KIRKY »

:lol: :lol: :lol: I’ll remember that next time hubby asks.
Cheers
Kirky
Great oaks from little acorns grow.
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Re: Oak tree and powdery mildew

Post by Mickeyjaytee »

Hey everyone!

So an update. I’ve applied the 50/50 milk and water combination twice over the past 2 weeks and the leaves on the oak have had a real nice dark green and have been fantastic. I also cut back the trees that were shadowing it so it’s getting nearly 8 hours of sun per day.

Today however I’ve noticed a new brown rust on some of the leaves. Does anyone know what this could be? Maybe the milk got burnt into the leaves or is it a new type of disease/pest?

Please help!

EDIT: As a side note I will say I did give it a control release fertiliser a few weeks ago. Also weekly I give it a combination of seasol and gogo juice. We did have a sudden snap hot day in Perth where it hit 31. With that said it does look more like a pest than anything else but, I am a beginner so I’m not certain
You do not have the required permissions to view the files attached to this post.
Mickey
User avatar
Sno
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 1198
Joined: January 16th, 2011, 12:26 pm
Bonsai Age: 0
Location: Crackenback NSW
Has thanked: 492 times
Been thanked: 614 times
Contact:

Re: Oak tree and powdery mildew

Post by Sno »

My guess it would be where the mildew ‘ate’ into the leaves when they were young .
Mickeyjaytee
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 286
Joined: October 2nd, 2022, 8:25 am
Favorite Species: Shimpaku Leptospermum Kunzea
Bonsai Age: 1
Location: Perth, Western Australia
Has thanked: 241 times
Been thanked: 27 times

Re: Oak tree and powdery mildew

Post by Mickeyjaytee »

Sno wrote: October 21st, 2022, 7:54 pm My guess it would be where the mildew ‘ate’ into the leaves when they were young .
Thanks for the reply Sno, I appreciate it. This is what my house mate suggested and I guess it does make sense. The only problem I can see is that my second oak in a pot who was developing powdery mildew also has not developed this.

Early days though as to I only noticed this yesterday. I think you are most likely correct. The leaves have only been affected on the top and underneath is still smooth and as normal.

Thank you!
Mickey
Post Reply

Return to “Pests and Diseases”