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Basil leaves have brown lesions then wither and die

Posted by BrianShiau none (My Page) on
Mon, Apr 23, 12 at 12:20

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. 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 that is ultimately resulting in plant death.

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

Day 1: Lesion on top leaf
Day 1: Closeup of leaf
Day 2: Lesion spreads to lower leaves
Day 5: Leaves wither (but tiny new leaves look fine)

Follow-Up Postings:

RE: Basil leaves have brown lesions then wither and die

maybe cause they are all growing sideways .. man those pix hurt...

are you absolutely positive you diluted the product you sprayed on properly ...

if you had no problem until you sprayed.. does that mean anything???

looks like chemical burn to me ... and as soon as you remove one.. the one below.. coming into more light.. then burns ....

one thing that comes to mind.. when trying a new product.. experiment on 'some' rather than 'all' ...


RE: Basil leaves have brown lesions then wither and die

Sorry Ken, the pictures are right side up on my computer I don't know why some turned sideways when uploaded.

Biota Max is not a chemical, its contains strains of Trichoderma (a fungus) and Bacillus (a bacteria). The microbes colonize on roots so I sprayed the solution on the roots.

I do spray a neem oil solution on leaves, but I have been doing this for a long time w/o this leaf problem arising. I will stop the neem oil spray and see if the problem persists. Thanks.

RE: Basil leaves have brown lesions then wither and die

Brian, I would certainly contact your local extension office to see about sending plant samples to your research university's plant pathology lab. They (office staff) should be able to tell you how to collect and pack the samples so that they get to the lab in the best possible condition for evaluation.

I am pretty much totally ignorant of NFT or other hydroponic systems of plant culture. What benefit does Biota Max provide outside of a soil based medium?

RE: Basil leaves have brown lesions then wither and die

Rhizo, thank you very much for you suggestion--that is a really good idea. I'm going to look into that now.

Since hydroponics doesn't use soil, such systems lack the naturally occurring beneficial microbes that inhabit the soil. Normally, pythium microbes could be eaten by trichoderma microbes living in the soil.

In a hydroponics system, the trichoderma colonies will not naturally be there, so pythium may arrive through airborne spores and colonize plant roots with impunity. It's just like bringing in an invasive species in which natural predators are not there to control the population. The microbes in Biota Max would inhabit the root structure of the plant, defending it from harmful microbes.

RE: Basil leaves have brown lesions then wither and die

I'm not sure I'd call those "lesions", but that's just me. I wonder though why gimmicks would be needed to grow basil. How about starting with good-quality seeds, use healthy soil, and then water them and give them light? Adding things that aren't part of the normal equation usually leads to problems.

Maybe a less science-lab stuff would help. Good luck.

RE: Basil leaves have brown lesions then wither and die

Yikes, I sure do disagree, JimR! Forms of hydroponics have been around and known to be successful for generations. Some people would argue that taking the soil OUT of the equation makes it easier, MUCH easier. It simply requires veering off the beaten path a bit and learning some new principles. After all, plants have very few requirements....water, light, air, dissolved nutrients. They can get all of those things without the benefit of soil in any form.

I've not experimented with hydroculture, hydroponics, or aeroponics myself, though I daresay that my years of growing in a completely soilless medium (Turface, granite grit, bark fines) might qualify. But I know many that have, including successful commercial growers of leaf crops, tomatoes, and cucumbers.

I've spoken with hydroponic growers of cut flowers for the florist trade, which is becoming more and more popular. I visited Epcot about 30 years ago and remember being really amazed at their underground aeroponics system. For some reason, the huge squash plants stand out in my memory, suspended in the air with roots hanging below...covered with ripe yellow crooknecks!

So, not a gimmick at all but tried and true agricultural methods that have been around for many, many years. It's only natural that the methods have been down-sized for use in basements and small greenhouses.

Here is a link that might be useful: Take a look at this.

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