Bacteria or what on oak?!?

melisan

My oak is not very healthy. I pulled off lots of leaves tonight thinking it could be a bacteria. Not too sure. I found aphids or agelids (not sure) nesting 2 nights ago and did a neem oil on it last night. No more bugs but the leaves look unhealthy. I am not sure if it is from bugs or bacteria or what. I really want to build this tree back up to good health. It just underwent a major root layering job on Saturday!

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Will_Heath

Check out this page for possible culprits.


Will

melisan

I checked out the pics on that site you gave me. thank you but no luck.

I have been looking in a gardening book to try and identify what the heck is happening. These leaves may be one thing, but more likely multiple things are happening from what I can tell.

1. Perhaps the yellowed leaves are an indication of a nitrogen deficiency.They just appeared after I root layered on Saturday although I did not disturb the old roots at all. Maybe the plant is shocked by having the trunk removed??
2. The yellow and green leaves with blotches perhaps are from pseudomonas bacteria. My garden book suggested to remove all of the affected leaves which I tried to do.

3. Some of the leaves have just brown spots which may be a fungi, cocomyces hiemalis. The treatment is to imporve the general growing condition and the overal health of the tree.

So, what my plan of attack is to fertilize this weekend with miracle grow 1/2 strength. I feel like this plant really needs a boost after it was just root layered. I probably should not water on the leaves just incase this is spreading a bacteria.

Any other ideas anyone has
thanks
Melissa

TreeBay

Wasps often lay eggs on oak leaves, usually on the underside of pine leaves. They look like small green apples about the size of the head of a stick pin, but they increase in size. On the opposite side of the leaf there is usually a distortion and discoloration. Later on the eggs drop away, so you might check the backs of other leaves on the tree.

How is the current flush of growth doing?

Another possibility is leaf miners - you can see some detail on those in the wiki Leaf miner

Regards,

Matt

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melisan

Hi Matt.
Thanks for your input. I did notice one leaf with the "leaf miner" which I just removed. I don't think there are wasps laying eggs, however.

I checked out some oaks today on my walk and noticed the same types of leaf problems as mine. So it is not just my tree that is attracting whatever to it.

So, hopefully, by me removing those leaves, nourishing the tree, and keeping the environment clean, that the tree can withstand whatever is eating on it without it dying. I did treat it with Neem oil and so far, the leaves seem to be aphid free. I am making a point not to water the leaves either.

There is some new growth albeit small. But some is better than none. I have only had the tree since May 1 so I am really trying to figure it out.

Matt, would you suggest something other than 1/2 strength miracle grow? I last fed it on May 1.

Thanks for you input,
Melissa

John Dixon

melisan,

Have you considered fungus? I know that oak are prone to mildew, and I use basic fungicide on my english oaks. I am going to use liquid copper this year. I haven't used it before, but I did a little research and found that fungus will not co-exist with copper. Shingle roofs and prone to black streaks (this is a fungus) and there are items on the market like copper plates that are installed on roofs to prohibit the growth of fungus. Now some shingles are impregnated with copper. The liquid copper is marketed as a fungicide and I really think this is advantageous for mildew and fungus prone bonsai material, but it's just theoretical at this point. The testing phase (for me) is just beginning.

Your photos to me look like mildew or black spot damage (like on roses). I'm not sure if black spot is only limited to roses, but the treatment is to keep the foliage dry, remove infected leaves, pick up any infected material, and make sure there is good air movement around the plant. I would suggest keeping the watering limited to the soil on your bonsai. If it is a mildew, then that should help tremendously. Fungicides, in general, will help with any type of fungus/mildew and anthracnose.

It took a while, but I found some info on anthracnose. See if that could be it.

http://ianrpubs.unl.edu/plantdisease/g1200.htm#oaan

Good luck,

John

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John Dixon

Si vis pacem parabellum

Stay off the trails of others, that's where the booby-traps are.

Jgs bonsai

I think your tree will be fine and it is only dropping its old leaves. Many of my oak trees are doing this now. I have sent you a PM on this subject. I hope you are set up to recieve them.

Jgsbonsai

ALDEVAUX

Melisan, by taking a close look at the leaf spots you show in your pictures, it seems to me that they are similar to many leaf spots that I have often seen on different plants which can be caused by non parasitic agents.

In fact,plants can be affected by disorders caused by non parasitic factors such as air pollutants which vary with the concentration of the pollutant in the atmosphere, the duration of exposure, the natural sensitivity of the plants, and the environmental conditions affecting the plants before and during exposure.

Injuries by air pollutants are classed as acute or chronic. Acute injury are asociated with brief periodes of greater than normal air pollution which results from rapid absorption of enough toxicant to kill portions of leaves, causing characteristic spots on the leaf surface.

The most common types of air pollutants are oxidants (ozone, oxides of nitrogen, and peroxyacl nitrates), sulfur dioxide, and fluorides (hydrogen fluoride and silicon tetrafluoride).

In general, air pollutants are rarely found in sufficient concentrations to inflict significant damage on landscape plants, but in certain areas where there are manufactures that pollute the environment such as large chemical plants, they can be in sufficient amounts to cause damage especially on plant with young leaves develloping.

This is probably what affected your trees since you also found the same symptoms on other trees in your area.

Alasdair

John,
I've used copper based fungicide sinse i got a heavy bout of mildew last year. I have noticed it works a treat.

Al

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