Rusty-colored leaves: Deficiency or Fungi??

[A4]

The more I look at this picture the more it is beginning to look like some type of nutrient burn. From the way the leaves are curled it appears that it is possible when foliar feeding, leaves captured some of the nutrient and caused a burn. If you look at the cupping on the leaves you can see that it appears to be a trench and that most of the burn is inside the trench. Also if you look at the back of the leaf it appears to be mostly unaffected except at the stem where it would have run under the back side. Further if you look near where the leaf connects to the stem, there appears to be some pooling there. Right now that is the best that I can guess. I wish I had more information to give you but I'm as curious as everyone else.

 

[Papa Munch]

I agree that its very frustrating. I have had this and the odd thing is that it looks exactly like rust.

As we're trying to figure this out, I found this on Rust Fungus in another forum......

rust, how many of you have had this and been beaten by it? lots i bet!!!
first, rust is a fungi. it is opportunist. it preys on unwell plants. if something is a miss, rust is a sign. rust has been identified to have 7,000 species. it attacks crops of every description. but we're only interested in one variety arn't we?
if rust is present early in a grow, you have problems as it's an indicator something in your room is a miss. usually ventilation. go through your system and double check things are in place and working properly.
rust is an air borne fungi. if given the opportunity, it WILL take hold. it usually does during flower as this is when the plants immune system is at its weakest as its energies are concentrating on re-production, not survival.
depending on what part of the grow you get it, you can cure/minimize it with either chemical or natural remedies.
it enters the leaf via the stomata and then it's off and running.

fungacides used are generally copper based and include; thriram, manzecob, maneb or zineb at 10 day intervills.
organic;
baking soda, 1 tea spoon/ quart of water. spray on.
copper sulphate, read lables.
fungacidal soap sprays;
garlic sprays, 1/2 cup minced garlic, 1 quart of water. let sit 24hrs, strain, spray.
sulphur, one of the best natural sprays. it is low in toxicity.
micro kill, a citric based killer. i use this with great success

 

[TimeTraveler]

I saw that EXACT same post when researching my problem, Papa Munch!

No clue which I'm dealing with; I'm already letting the garlic mix steep to use in the next day or two if it doesn't improve.

@A4 The more I look it over the more I'm inclined to believe you're right. On further inspection of my plant, most of the stains are circular (like a droplet that sat too long) or occur within a border of green in certain leaves. It's also harder to find within the bushier, denser parts of the plants. Both seem to support your hypothesis. Also, I made a fairly strong tea for both watering the soil and leaves as a sort of extreme response to some severe nutrient deficiency: only a week into flowering and my plant's lower fan leaves were dying off like you'd see at the end of a grow. It stands to reason I might have been a little TOO aggressive in responding to the crisis. Again, I'll keep everyone posted and we'll see.

 

[TimeTraveler]

Well, something worked. The sample leaf today looks better than before. Here, again for easy reference is Day 0 and Day 1, side by side:

Followed by Day 2 (today, how it looked on opening the box):

There's a noticeable decrease in the rusty discoloration, and the healthy green of the leaf is showing through from underneath.

Whatever the root cause of the issue, the triple-threat approach of more P in the soil, a light water washing, and then peroxide spray has seen it diminish; while that doesn't narrow down at ALL what might have caused it, I'm more relieved it appears to be leaving.

 

[Waira]

...looks better every time, mate! - it's a stain of some type,... more noticeable now, is the way it follows and settles into the lateral veins depressions...nothing pathogenic will do that! So, no need for garlic or any other stuff to treat such micro-vermin, and worse, affect the flavor of the buds! Anything with strong aromatics, like the various pesticidal oil sprays likely would mess with your buds aromatics,...

 

[TimeTraveler]

Yep, looks like it's going to be alright, and a good job too: the main cola on that Sugar Black Rose (the one too far along for Neem or other extreme measures) is getting ridiculously fat!

Big, BIG thanks to everyone who's helped me out. I'll be trying to send some rep slaps out in appreciation, just as soon as I figure out how many points I can divvy up!

 

[Waira]

Cheers TT, much obliged!...and you're welcome of course,.... Rep' can be given as much as you want, only you have to pass it around some (5 people?) before you can rep' the same person again,...

 

[Renaissance Redneck]

There's a noticeable decrease in the rusty discoloration, and the healthy green of the leaf is showing through from underneath.

Looking much better, Traveler!

 

[Papa Munch]

How the girls doin today TT?

 

[TimeTraveler]

How the girls doin today TT?

Looking great! The SBR is getting fatter ever day, and I can't wait. The Massive Midget is starting to get orange hairs on top of her growing buds, so she's on point to become a hell of a harvest. Here's today leaf shot:

Not much improvement, but it's there. Slowly but surely getting better, it seems.