Burn leaves in Azalea

[nilushi]

Here are the pictures of my two Azalea which shows browning of some leaves. Everything hapened overnight.

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Usually i water in the morning - daily hot days ,otherwise as required, check with chopstick.
Fertilizer- every 2 weeks with compound fertilizer (NPK 10:6:10). I am suspecting fertilizer burn.Last time i fertilized them in fairly hot day(>30C)
Is this having any conection with fertilizing in hot days?
Greatly appreciate your coments.
Thank you.
Nilushi

[Bretts]

The advice I was given was browning from the inside of the leaf out was a sign of overwatering.

[anttal63]

sorry for my ignorance; what is a compound fertaliser? if done by liquid did you wet the leaves with it, was the the soil wet b4 you applied ??? btween 30 to 40 deg. i water morning and night. 40 and over 3 times a day. in any case i dont think this is a cause to burn leaves just simply cut them off and in the bin. maybe a bit more protection from hot sun and winds.

[BoNZai]

don't think this is fert burn, in my experience fert burn starts at the tip of the leaf, starts yellow and then becomes necrotic (brown, dead)
Overwatering normally starts as yellow leaves.
Your pics look like a physical deformaty. What does the underneath of the leaf look like? Insects? Mites?

Cheers

BoNZai

[anttal63]

i think its fert burn if watered in and on the foliage on a hot day. omo

[Pup]

From the book what pest and disease is that by Judy McMaugh

Azalea
Rhododendron spp

Brown spots or patches on leaves may be a fungal leaf spot, or may be caused by Azalea leafminer.

They may also become sunburnt if exposed to too much sun and wind.

From personal experiance wind on a hot day can do more damage to leaves than ferts or salts from water.

I must admit that I have not seen this problem on any of my Azaleas. That is why I quoted Judy McMaugh.

Cheers Pup

[nilushi]

Thank u for your suggestions.
Little more about sunlight - Both trees having morning sunlight up to 10-11am , not much wind
The second tree ,i re-potted 4-5 weeks ago and both showed spurt of growth recently.