Lessons from the Bogarden: Diseases

We invested a lot of time to producing seedlings for the bogarden. Unfortunately, due to factors beyond our control something we used in the garden was contaminated with the spores of the fungus (septoria leaf spot) that infected our tomato plants! It was first evident that there was something wrong when they did not grow anymore after we transplanted them into the garden. Next, the leaves turned yellow and eventually developed little black spots that rotted from the inside out. Unfortunately, many of the tomatoes were all planted in the same bed so they all contracted the disease. This should be a lesson to everyone to avoid mono cropping and use companion planting to reduce the risk of diseases spreading throughout the crops. Also, a local master gardener suggested a few things. Here's what she had to say:

"Good garden hygiene is very important. Make sure you dispose of all the infected leaves and clean your tools when you switch working with different plants or areas"

"Once the tomatoes have it, the soil is contaminated because the fungus is spread by spores. I would start new tomato plants in different areas and replace the tomatoes with a different crop."

"You can help prevent fungus in tomatoes by keeping the leaves dry; most plants don’t like their leaves wet so when you water water around the base of the plants."

Also, an online resource had this to say about the fungus. It is surprising to me that its development was so widespread due to the relatively low humidity we have had in Charleston this spring.

"Because free moisture is necessary for spore infection through stomates, long-lasting dew and rainy days (100 percent RH for 48 hr accumulated over several days) favor disease development."
Also, the only way to get rid of a fungus involves use of fungicides that are dangerous substances to other organisms. She also said:

"trying to get rid of the fungus involves things I wouldn’t use in my garden and the plants never really thrive after that."

I though it was also interesting that the fungus can be carried in the seeds. Thus, buying seeds from large seed producers (which is where we got our tomato seeds) may risk your plants contracting the fungus. The Cornell's gardening website (http://vegetablemdonline.ppath.cornell.edu/factsheets/Tomato_Septoria.htm) said:

Tomato seed has been shown to carry spores and produce infected seedlings, but whether the pathogen is truly seedborne is unknown.