Unidentified red/brown spots on leaves: It can be fungus so jump in and help

[TriangleCheese]

Hey folks,

I have these spots for a while and I couldn't really get what is actually wrong. It looks like P deficiency but I got the pH right and I have been feeding mild. I am afraid of leaf septoria but I have a nice air circulation in the tent so it is probably a deficiency. I am using Biobizz FishMix as main veg nute and I know that it has P in it. I am always feeding with pH 5.8-5.9 and using Coco. Just wanted to post here to be safe.

Any help would be greatly appreciated

IMG_4481.JPG

• TriangleCheese
• Mar 4, 2019

IMG_4482.JPG

• TriangleCheese
• Mar 4, 2019

 

[Emilya Green]

I think it is a regular mildew, not powdery. (Phytophthora infestans) Treat with a fungicide and prevent with better air flow.

 

[TriangleCheese]

I think it is a regular mildew, not powdery. (Phytophthora infestans) Treat with a fungicide and prevent with better air flow.

Thanks for your response. It looks like fungus right? Any fungicide you can suggest? I think can find an equivalent here. Or I guess I can use potassium bicarbonate or hydrogen peroxide.

 

[Emilya Green]

Thanks for your response. It looks like fungus right? Any fungicide you can suggest? I think can find an equivalent here. Or I guess I can use potassium bicarbonate or hydrogen peroxide.

Integrated Pest Management | Pro Farm Group - Formerly Marrone Bio Innovations

Pro Farm Group, formerly Marrone Bio Innovations, is a global leader in biological crop solutions. We are pioneers in developing effective, safe integrated pest management (IPM) solutions for specialty crops, row crops and water systems.

www.marronebioinnovations.com

 

[TriangleCheese]

Integrated Pest Management | Pro Farm Group - Formerly Marrone Bio Innovations

Pro Farm Group, formerly Marrone Bio Innovations, is a global leader in biological crop solutions. We are pioneers in developing effective, safe integrated pest management (IPM) solutions for specialty crops, row crops and water systems.

www.marronebioinnovations.com

Thank you for this suggestion. I can't order that fungicide here but I will look for some alternatives. Do you think I should remove affected leaves?

 

[Emilya Green]

Thank you for this suggestion. I can't order that fungicide here but I will look for some alternatives. Do you think I should remove affected leaves?

I would, after applying fungicide to everything nearby.

 

[TriangleCheese]

I would, after applying fungicide to everything nearby.

I hope I can get my hands on a good fungicide. What do you think about using hydrogen peroxide and potassium bicarbonate? As far as I can remember they work in some cases.

 

[Emilya Green]

I hope I can get my hands on a good fungicide. What do you think about using hydrogen peroxide and potassium bicarbonate? As far as I can remember they work in some cases.

I do not know... hopefully someone else can comment here so you can find a home remedy.

 

[TriangleCheese]

I found this nearby. I hope that works. It doesn't specify all of the the target fungus species but they say it kills powdery mildew. Can we say it also kills the mildew on my plants?

Amanitha fungicide by Agrobacterias - GB

Amanitha Fungicide by Agrobacterias is a very useful product, particularly effective for preventing fungi infestations such as oidium or botrytis.

www.growbarato.net

 

[Emilya Green]

I would think it would work... just make sure its active ingredients are safe

 

[PE636]

I once tried a dilute milk and water solution on powdery mildew on an outdoor plant. Worked awesome.. Honestly not sure if it might work for other mildews or fungus but thought I would mention it.

 

[Emilya Green]

I once tried a dilute milk and water solution on powdery mildew on an outdoor plant. Worked awesome.. Honestly not sure if it might work for other mildews or fungus but thought I would mention it.

I have heard of that, never tried it though.

 

[TriangleCheese]

They are promoting this one as %100 natural. I don't have any other choice though. Usuall self-made remedies sound fine but I think this is a case when you just want to solve the problem as fast as possible without doing an experiment. I will definately give that Amanitha a try.

 

[TriangleCheese]

I have heard of that, never tried it though.

That is a very common recipe for DIY fungicide. The full recipe is two teaspoons of apple cider vinegar to 1L of water. Then mix 60% milk and 40% of that water for foliar spraying.

I won't go crazy with DIY stuff for this time. If Amanitha won't work, I will give it a shot then. I will max the fan setting as well.

 

[PE636]

I have heard of that, never tried it though.

I had a 4 foot tall bag seed plant growing in the woods near home and it got a moderate case of pm, it was on quite a few leaves, luckily still in veg. Asked a long time outdoor grower what to do. Gave her the milk treatment next mid morning (important to do it in the light apparently). 2 days later you would never have known about either the PM or the milk treatment, I was quite impressed.. I think it was 8:1 water to milk (I used whole milk) if I remember right.

 

[TriangleCheese]

Just found this on a grow website. Looks just like my leaves. Can it be Magnesium deficiency? I am feeding them with minimal amounts of Advanced Nutrients Cal/Mag. I have increased the amount 4-5 days ago but I cropped more leaves with spots today. I thought FishMix had enough Cal/Mag in it but apparently not. Do you guys think this case is caused by Mg deficiency?

Magnesium (Mg):
-Commonly deficient in Cannabis
-Yellowing of lower leaves progressing upwards with severity
-Interveinal yellowing
-Rust brown patches on leaf margins, tips and between veins

 

[Emilya Green]

I had a 4 foot tall bag seed plant growing in the woods near home and it got a moderate case of pm, it was on quite a few leaves, luckily still in veg. Asked a long time outdoor grower what to do. Gave her the milk treatment next mid morning (important to do it in the light apparently). 2 days later you would never have known about either the PM or the milk treatment, I was quite impressed.. I think it was 8:1 water to milk (I used whole milk) if I remember right.

I love it... a natural bacteriological attack. Now I want to try it!

 

[Emilya Green]

Just found this on a grow website. Looks just like my leaves. Can it be Magnesium deficiency? I am feeding them with minimal amounts of Advanced Nutrients Cal/Mag. I have increased the amount 4-5 days ago but I cropped more leaves with spots today. I thought FishMix had enough Cal/Mag in it but apparently not. Do you guys think this case is caused by Mg deficiency?

Magnesium (Mg):
-Commonly deficient in Cannabis
-Yellowing of lower leaves progressing upwards with severity
-Interveinal yellowing
-Rust brown patches on leaf margins, tips and between veins

That looks a lot different... those rusted areas are crispy and gone and dead... crinkly even. Your leaves are not doing this, they are mottled and discolored, but not yet necrotic.

 

[TriangleCheese]

I love it... a natural bacteriological attack. Now I want to try it!

As far as I know, vinegar kills some of the beneficial growth in your rootzone so you might want to think twice before adding it into your medium. Vinegar also kills leaves or plants themselves. I think you should only apply that to the infected area. Good thing it is natural but not totally safe.

 

[TriangleCheese]

That looks a lot different... those rusted areas are crispy and gone and dead... crinkly even. Your leaves are not doing this, they are mottled and discolored, but not yet necrotic.

These pictures were taken with photo-flash on. I got lots of other leaves looking exactly the same. I will share some more tomorrow. Do you think that picture from that grow website is a good example of Mg deficiency?