What are these yellow/brown spots on my tomato plants?

[Augustmomx2]

I need some professional opinions (that means you guys of course!). What the heck is going on with my tomato plants, I'm noticing this:

Is it fungus? Any opinions or ideas would be greatly appreciated...thanks

 

[bigredfeather]

Yes it is a soil fungus. If you notice, it almost always starts at the bottom and works its way up. When ever it rains or you water, the water bounces up and gets the fungus on the vegetation.

I have tried something this year that has really helped. As my plants grow, I trim off all vegetation near the ground. This prevents the fungus from ever getting started. So far, I haven't had any problems, where in years past, I have had plants completely engulfed by mid-August.

If you do have an infected plant, trim off infected area, making sure not to touch it on any healthy part of the plant as it can spread by contact. A prevention method have read about but never tried is to mix 1 tablespoon baking soda and 1 teaspoon of any type cooking oil (corn oil is recommended) per gallon of water. Spray this solution directly on the plant. The ph of the baking soda will kill the fungus and the oil will prevent future fungus spores from attaching to the plant. You will need to do this once a week or after it rains.

I was getting the fungus up higher on my plants a few years ago. At first, I couldn't how it was getting started. After thinking about it, I realized it was coming from my tomatoe cages. The plants had been infected the previous year, and the fungus was on the cages, spreading it to the current years tomatoes. Now I fill a container bigger than the cages with water and add some bleach. I dip the cages in the bleach solution prior to putting around my tomatoes. I haven't had any problems since.

Hope this helps.

 

[vfem]

A.K.A. - Late Blight

Use an anti fungal treatment spray. Start in the morning EARLY as not to burn leaves. Spray, and respray every 5-7 days (as bad as yours looks start on 5 days), also after every rain and continue the treatments for the rest of the season.

To stop this fungus from happening try to mulch under your plants. Heavy rains can cause this as well as watering your plants not using a drip system. It causes the soil to jump up onto the bottoms of your leaves... the fungus is in the soil and only gets to the plant through the leaves.

Good luck... I hope you caught it early enough. I had it earlier this year, and managed to save all but 3 of my plants that had to be burned.

 

[Augustmomx2]

Thanks for the tips! It is spreading...a lot! It has gotten substantially worse, since most of my tomato plants fell a few weeks ago due to rain and winds. Its so odd, since one side (the side that was laying on the ground) is completely covered... the other side is just fine. I'm definitely going to try the oil/baking soda, I've purchased some anti-fungal stuff that seems to be keeping it at bay. Next year, I will sterilize my cages (never thought about that) & mulch like a crazy lady.

Thanks again

 

[bigredfeather]

Thanks for the tips! It is spreading...a lot! It has gotten substantially worse, since most of my tomato plants fell a few weeks ago due to rain and winds. Its so odd, since one side (the side that was laying on the ground) is completely covered... the other side is just fine. I'm definitely going to try the oil/baking soda, I've purchased some anti-fungal stuff that seems to be keeping it at bay. Next year, I will sterilize my cages (never thought about that) & mulch like a crazy lady.

Thanks again

I forgot to add about mulching. That is an excellent prevention method. If you cover the ground, it makes it harder for the fungus to reach the plants.

 

[insiderart]

As it turns out you have Early Blight (Alternaria solani), a common fungal pathogen of tomatoes. Hallmark is the dark lesion concentric rings of growth. The spores often overwinter in infected debris or soil. Once the initial infection occurs and begins to sporulate the spores can be carried by the wind, rain, birds, your clothing, etc. Most of the infection you see is secondary spread from airborne spores, from lesions on the lower leaves. You can try spraying every 7 days with Bravo. From a cultural standpoint planting your plants where they don't remain wet for long periods of time. Make sure there is sufficient ventilation around the plants. Don't work the plants when they are wet. Rotate your tomatoes to prevent reinfection the next year.

Remove any infected plant debris and dispose of it in the trash, do not compost your tomato plants.