Black spot on lettuce

[heidi critchfield]

I have black spot on nearly all my lettuce in my raft system. I understand that it is spread in dirt gardens by irrigating with river water and that sounds a lot like aquaponi water to me! Does anyone know what to do about it? Some sites suggest once you have it you may not be able to grow lettuce again (in dirt) without probs. Does anyone have a good source for resistant seeds or any other knowledge that might help?

 

[Converse]

I have not heard of BLack Spot on lettuce before...I do know that worm casting tea does stop Black Spot on roses.  My recommendation is to get some fresh worm castings (ones that have not been kept in a sealed bag - you need all the normal microbial population normally acssociated with worm castings alive).  Brew some worm casting tea.  If you need the directions let me know.  Spray the plants down with this AND the soil/media they are growing in.  Also, make sure the area where your black spot is present has good ventillation. 

    My best to you in this battle for your lettuce!.

 - Converse

[heidi critchfield]

Thank you for the reply! I'm sorry, it is actually bacterial leaf spot and is very common for lettuce in dirt gardens.---Not sure why it is on nearly all my lettuce. It is very damaging. At first it was only the mature outer leaves. I did spray with compost tea but will continue. I was actually worried that the tea may hve been the carrier since it showed up after I began using it. Thx for the suggestion on the fresh castings. I have been using purchased castings from a bag, but do have fresh ones. I would love to have your instructions in case I am doing it wrong! I just took some info from online...

Has anyone else dealt with Bacterial Leaf Spot on their aquaponic lettuce?
 
Converse said:

I have not heard of BLack Spot on lettuce before...I do know that worm casting tea does stop Black Spot on roses.  My recommendation is to get some fresh worm castings (ones that have not been kept in a sealed bag - you need all the normal microbial population normally acssociated with worm castings alive).  Brew some worm casting tea.  If you need the directions let me know.  Spray the plants down with this AND the soil/media they are growing in.  Also, make sure the area where your black spot is present has good ventillation. 

    My best to you in this battle for your lettuce!.

 - Converse

[Jonathan Kadish NYC AA Chair]

Question... Did you place anything in your system from a nursery or outside seedlings that you grew yourself?

[heidi critchfield]

Not in the aquaponic system. Yes on the dirt part of my garden.

 
Jonathan Kadish said:

Question... Did you place anything in your system from a nursery or outside seedlings that you grew yourself?

[Jonathan Kadish NYC AA Chair]

I have the same issue, that is why I asked. Is it possible that there was some cross contamination? I can't grow Basil, Lettuce & Arugula. I have been blaming it on a transplanted basil plant that I got from wholefoods.  Pseudomonas Cichorii is what it is called, and yeah you have to not grow species that can be infected for a year they say. I have been avoiding taking the system out of service and decontaminating it by growing species that will do ok. Bok Choi, peppers & A dwarf tomato variety. It sucks, but it is a lesson in bio-security.

[heidi critchfield]

OMgoodness! A year? The only thing I grow well in the raft system is letuce, basil and celery! Where did you see this for a year?

No, I don't think mine was due to cross contamination from the dirt garden, since it has not (yet) appeared in the dirt garden. I think it may have been on seeds? I read on line that seeds are often the source. I buy all my lettuce seed at Johnny's, but have used other companies for other plants and it is on my collards and broccoli as well, to a lesser degree. This is so sad.

I found some lettuce varieties listed on line that are somewhat resistant to it, but the study I read said they did poorly for the fall season, so maybe I have to wait for next spring anyway. Well I may try them now and spray the seedlings with Serenade before I put them in the system and then at the 7 day intervals as suggested on the bottle.

Now I'm really scared that it will migrate to the dirt garden! Sick...

Wow, this is a terrible setback! 

Thanks for your input, please let me know how you are doing with it over time, won't you? 

 
Jonathan Kadish said:

I have the same issue, that is why I asked. Is it possible that there was some cross contamination? I can't grow Basil, Lettuce & Arugula. I have been blaming it on a transplanted basil plant that I got from wholefoods.  Pseudomonas Cichorii is what it is called, and yeah you have to not grow species that can be infected for a year they say. I have been avoiding taking the system out of service and decontaminating it by growing species that will do ok. Bok Choi, peppers & A dwarf tomato variety. It sucks, but it is a lesson in bio-security.

[Damon Polta]

the transfer of disease mainly in two ways.

1. mechanical transfer. where two plants rub against eachother causing micro tears in the leaves inwhich disease and bacteria can get in.

2. injection or bug transfer. a bug lands and eats an infected plant, then move one to a new non-infected plant... this type of spreading would explain how the infected plants in the dirt garden could have spread the disease into the AP system.

also, one thing i learned by watering my grandmothers roses the wrong way... standing water on leaves and petals act as a lens, focusing the suns rays and burning or spotting the leaves...

really any kind of standing water on the leaves or excess moisture is a breeding ground and elevates the risk of bacterial disease and mildews... sometimes spraying, even though has proven at one point to cure a problem, can perpetuate the situation by keeping things moist... sometimes the best thing to do is to burn it all and start over... saves time and energy in the long run...

[Jonathan Kadish NYC AA Chair]

Well I don't have the reference, it was one of a million google searches. The year of waiting time was quoted to a dirt garden, so it may be different for a hydroponic set up. I read that too about the seeds but I tried many varieties and every one suffered. By the way is your system in a green house or outside & exposed?

I also read about Seacide which is cottenseed oil and fish oil to combat fungus and bacteria, but i don't know if it is safe for fish.

I will try lettuce again after this tomato crop is done and let you know the results.

heidi critchfield said:

OMgoodness! A year? The only thing I grow well in the raft system is letuce, basil and celery! Where did you see this for a year?

No, I don't think mine was due to cross contamination from the dirt garden, since it has not (yet) appeared in the dirt garden. I think it may have been on seeds? I read on line that seeds are often the source. I buy all my lettuce seed at Johnny's, but have used other companies for other plants and it is on my collards and broccoli as well, to a lesser degree. This is so sad.

I found some lettuce varieties listed on line that are somewhat resistant to it, but the study I read said they did poorly for the fall season, so maybe I have to wait for next spring anyway. Well I may try them now and spray the seedlings with Serenade before I put them in the system and then at the 7 day intervals as suggested on the bottle.

Now I'm really scared that it will migrate to the dirt garden! Sick...

Wow, this is a terrible setback! 

Thanks for your input, please let me know how you are doing with it over time, won't you? 

 
Jonathan Kadish said:

I have the same issue, that is why I asked. Is it possible that there was some cross contamination? I can't grow Basil, Lettuce & Arugula. I have been blaming it on a transplanted basil plant that I got from wholefoods.  Pseudomonas Cichorii is what it is called, and yeah you have to not grow species that can be infected for a year they say. I have been avoiding taking the system out of service and decontaminating it by growing species that will do ok. Bok Choi, peppers & A dwarf tomato variety. It sucks, but it is a lesson in bio-security.

[heidi critchfield]

My systems are all outside, exposed. I have given up trying to figure the how of it happening. I need to find a way to deal with it. This is a common lettuce/brassica problem so I am surprised you are the only person responding!
 
Jonathan Kadish said:

Well I don't have the reference, it was one of a million google searches. The year of waiting time was quoted to a dirt garden, so it may be different for a hydroponic set up. I read that too about the seeds but I tried many varieties and every one suffered. By the way is your system in a green house or outside & exposed?

I also read about Seacide which is cottenseed oil and fish oil to combat fungus and bacteria, but i don't know if it is safe for fish.

I will try lettuce again after this tomato crop is done and let you know the results.

heidi critchfield said:

OMgoodness! A year? The only thing I grow well in the raft system is letuce, basil and celery! Where did you see this for a year?

No, I don't think mine was due to cross contamination from the dirt garden, since it has not (yet) appeared in the dirt garden. I think it may have been on seeds? I read on line that seeds are often the source. I buy all my lettuce seed at Johnny's, but have used other companies for other plants and it is on my collards and broccoli as well, to a lesser degree. This is so sad.

I found some lettuce varieties listed on line that are somewhat resistant to it, but the study I read said they did poorly for the fall season, so maybe I have to wait for next spring anyway. Well I may try them now and spray the seedlings with Serenade before I put them in the system and then at the 7 day intervals as suggested on the bottle.

Now I'm really scared that it will migrate to the dirt garden! Sick...

Wow, this is a terrible setback! 

Thanks for your input, please let me know how you are doing with it over time, won't you? 

 
Jonathan Kadish said:

I have the same issue, that is why I asked. Is it possible that there was some cross contamination? I can't grow Basil, Lettuce & Arugula. I have been blaming it on a transplanted basil plant that I got from wholefoods.  Pseudomonas Cichorii is what it is called, and yeah you have to not grow species that can be infected for a year they say. I have been avoiding taking the system out of service and decontaminating it by growing species that will do ok. Bok Choi, peppers & A dwarf tomato variety. It sucks, but it is a lesson in bio-security.

[Jonathan Kadish NYC AA Chair]

A good PDF on leaf spot in peppers, it is a different organism but similar in modality

http://aces.nmsu.edu/pubs/research/horticulture/nmca30.pdf

These type of bacteria can apparently take a ride on a gust of wind. I guess if your exposed to the elements anything goes. Although there are a ton of people registered on the site, relatively few have been at aquaponics long enough to have seen problems like this. We are the leaf spot pioneers! Lucky for us.

[heidi critchfield]

Thx  Damon. It appeared in AP first and out of no where, seemingly. Very disheartening.
 
Damon Polta said:

the transfer of disease mainly in two ways.

1. mechanical transfer. where two plants rub against eachother causing micro tears in the leaves inwhich disease and bacteria can get in.

2. injection or bug transfer. a bug lands and eats an infected plant, then move one to a new non-infected plant... this type of spreading would explain how the infected plants in the dirt garden could have spread the disease into the AP system.

also, one thing i learned by watering my grandmothers roses the wrong way... standing water on leaves and petals act as a lens, focusing the suns rays and burning or spotting the leaves...

really any kind of standing water on the leaves or excess moisture is a breeding ground and elevates the risk of bacterial disease and mildews... sometimes spraying, even though has proven at one point to cure a problem, can perpetuate the situation by keeping things moist... sometimes the best thing to do is to burn it all and start over... saves time and energy in the long run...