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Basil plant leaves have brown lesions then death

BrianShiau
11 years ago

I am growing basil in an indoor NFT system. I recently treated the plants using a product called Biota Max which is a pro-biotic containing various strains of Trichoderma and Bacillus. Trichoderma is used to kill pythium and other fungus that can cause root rot. This is my first time using this product.

A couple weeks after treatment, my basil plants started exhibiting brown lesions on the leaves. The lesions would start at the top of the plant and work their way to lower leaves. I would remove the leaves but the lesions would appear on other leaves in the following days. This has begun to be an epidemic in my NFT system, spreading to other plants, that is ultimately resulting in plant death.

Pictures of the lesions are posted in the following links. What could be causing the lesions?

http://brianshiau.com/plants/Day_1_lesion_at_top.jpg

http://brianshiau.com/plants/Day_1_closeup_of_lesion.jpg

http://brianshiau.com/plants/Day_2_lesion_spreads.jpg

http://brianshiau.com/plants/Day_5_plant_death.jpg

Comments (4)

  • grizzman
    11 years ago

    That reminds me of plants dying from root damage or drowning. Basically a lack of oxygen. Also, some of the plants in the background appear to have some nutrient deficiencies (the yellowing between the leaf veins)
    Why did you add the biota product? are you experiencing a pythium problem or was your effort a preventative measure?

  • BrianShiau
    Original Author
    11 years ago

    Grizzman, thanks for the reply.

    I have had damping off problems in the past and it has been my biggest issue in growing and so I've been trying different methods of mitigating this risk.

    My damping off problems in the past have been in the seedling stage while growing in peat pellets. It is possible that some plants that had looked fine (but were in fact colonized by pythium) were transplanted into the NFT. My damping off problems in the past exhibited leaves blackening from the tips, from the bottom of the plant and working their way up. This problem is brown lesions forming from the middle of the leaf, from the top of the plant and working its way down. Do you think its a different kind of blight?

    The NFT itself has well aerated water. I have an airstone in the reservoir and the water falls a good distance from the channels into the reservoir. The water is very clear and there is no smell. The plants sit in net cups so there is at least an inch of roots that are entirely in the air.

    I have capillary matting at the bottom of my channels, which the roots started getting stuck to--I don't know if this has some implications for damping off.

    Also, this has only been affecting the basil plants in the NFT system. I have kale, onion, dill, and parsley that appear to be unaffected so far.

    Yeah there were some nutrient deficiencies for a while when I experimented with just running water with no nutrients for a week to see if my water stayed more clear and stop smelling. Adding the Biota Max made the water very clear and stopped the smell, so it does appear to be preventing harmful bacteria growth in the water.

  • grizzman
    11 years ago

    Everything I looked up implied a blight was killing your plants. Its possible they're not affecting the other plants as those might have some kind of resistance to it.
    sorry I couldn't be of more help.

  • BrianShiau
    Original Author
    11 years ago

    Just to follow up, it turns out the problem was an accumulation of salts in the NFT system. I scrubbed all my parts and flushed the plants with just water for a while and the plants have recovered.

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