Black spots on yellowing tomato plant leaves

A couple of days ago I noticed that one of my precious tomato plant was not well and I thought that it was some kind of bug attacking it like aphids. Did the soap water treatment and some of the leaves turned yellow. I washed the plant with clean water 5 minutes after treating it with soap water so it couldn't be the soap water treatment.

This morning some black spots start to show at the yellowing part of the leaves and bacteria infection comes to my mind.


Bacteria ??? ( photo / image / picture from KK Ng's Garden )
(Sorry for the blur photo. Taken without glasses on )
I then armed myself with a pair of shears and started snipping all the infected leaves whole ... did I do it right?

Moderator's note: added a more descriptive title to topic

 

Might be blight. Clippings should not lay on the ground and should be burned.

 

Not sure what it really is, KK, but I would be more inclined to think of a mold issue with your high humidity.
A spray to try would be either a milk spray (1 cup of milk to about a gallon of water) or a baking soda spray (1 teaspoon to 1 quart of water and 1 teaspoon of dishsoap) to see if that helps. Or buy a fungicide if you have them available to use for tomatoes there.
The tomatoes in my garden that are planted behind my greenhouse look the nicest where the greenhouse fan constantly is blowing on them... just an experiment for you to try since it was just an observation for me, but maybe a fan blowing on the plant might help if there is some protection from it getting rained on.

 

I think Carolyn has it right. A fan really will help dry the leaves and keep mildew and mold from growing.

 

Thanks Barb, I had the clippings disposed of far far away.

Thanks Carolyn I wish that is the problem. Even though the humidity is very high, the water on the plants evaporate real fast because of the heat and breeze. Out of the 3 plants in the same condition and location, one is having this problem - sorry I did not mentioned this earlier.
One of my suspicion that I cannot investigate is that the possibility of beetle grub eating the affected plants roots. To confirm my suspicion I will have to dig up the whole plant.

Thanks Mart, there is no fungus growing on the surface of the ground in the container and I made sure that the grow media is never damp but just moist. I think it could be those beetle grub because I had lots of problem with them recently and I lost all my pepper plants to them.

 

The soda / water mix worked for the powdery mildew on our Squash and Zucchini. Also on cucumber vines. We have very humid summers, usually.

 

Thanks Growingpains, the plant looks better now after removing the leaves.

 

Black Spot Remedy

I found this remedy on another garden site. It worked very quickly. 2 uncoated aspirin (325mg), 1 Tablespoon molasses, in 1 quart water. Spray twice weekly.

 

Thanks and welcome SRL123, I'll keep that in mind.

 

It may also be Pseudomonas siringae pv. tomato.

 

That is awful Macshadow, I hope it is not that!

Thanks for the info.

 

Have you figured out if its the grub or something else? Good that its doing better.

 

Yes Mart, it has nothing to do with the grub. I dug out the plant yesterday and wash the roots clean and also all the earth in the container to look for grubs but there was none. I figured that it must be blight. After removing all the infected leaves, the plant must have gone into recovery because there was no growth, it just remain the same size. Anyway I planted it back with a dose of Epsom salt and compost around its roots. Keeping my fingers crossed that it will recover fully.

 

Mate, if it was blight, your tom plant would be dying or dead by now.

If it is not growing AFTER your removal and root-cleaning, there will be a period of 2-3 weeks when the plant will do nothing...that is normal. It is quietly recovering from its trauma.

 

Thanks Sjoerd, so I guess the mystery is not solved. From now I guess it is a waiting game.