Need Help Diagnosing Systemic Disease - (pics)

[rnewste]

This year, I have been hit with something I've never seen before.



Interesting thing is that this is appearing only on the sunny side of the plants - not on the North facing side:



From listening to Carolyn and others on TV, I have concluded it is a systemic disease, as not only the leaves are infected, but so too are the vines:



In fact, some of the main vines are looking actually kind of gnarly:



I'd appreciate any kind of identification / treatment, as I've been spraying with Exel LG, without any meaningful suppression of the disease.

Thanks,

Raybo

[carolyn137]

Ray, check out Alternaria Stem Canker b/c the stem and leaf and fruit lesions seem to match although there is a bit of a problem with some lesions showing up purple when they shouldn't be. No doubt a photography problem.

But to me Alternaria Stem Canker seems possible and the interesting thing is that it's found mainly in Califormia.

Look at some good disease sites such as Tamu or Cornell or look at Google IMAGES, or just plain Google it and see what you think.

[amideutch]

http://www.ipm.ucdavis.edu/PMG/r783101311.html

http://www.seminis.ru/resources/dise..._blight_en.asp

http://www.sciencedirect.com/science...6894529290032H

[rnewste]

Carolyn and Ami,

Thanks very much for the analysis. The spots / lesions are black - not purple, and as you say Carolyn, it was photography late in the day that mis-colored the pictures.

From one of the links Ami referenced:

""For plants that have already become infected, it may be necessary to use a fungicide spray to save them. While the disease cannot be completely eradicated, it can be controlled through spraying. There are several commercial fungicides available. Preparations containing mancozeb are particularly effective, as are copper sprays for tomatoes. Chlorothalonil, mandipropamid and fluopicolide are effective fungicide ingredients, when treating the disease in later stages.""

I've resisted using Daconil for the past several years, but this seems to be the only effective fungicide. I was hoping a more benign spray such as Exel LG would help, but Alternaria Canker seems to be a pretty aggressive problem, from what I am reading.

Last year it was the bugs - Tomato Russet Mites, Psyllids, and Aphids. This year it is Fungal. Well, considering the much wetter and colder Spring and Summer we are having, I guess I shouldn't be surprised.

Raybo

[carolyn137]

Ray, Alternaria Stem Canker is a systemic disease so spraying with anti-fungals I don't think will help. Of course you can try it, but here's what my Tomato pathology monograph says about Control of this disease:

( it is difficult to control this disease with fungicides so resistant varieties should be used.)

And in the symptoms section they say that " all above ground parts of the plants can be infected." And you showed that with your pictures.

So right now I think the only recourse you have is to remove as many infected leaves and fruits that you can and spray the heck out of the plants, and my choice would be Daconil as being THE most effective antifungal, but the choice is yours. And there's no harm alternating that with Mancozeb or whatever.

[rnewste]

Originally Posted by carolyn137

So right now I think the only recourse you have is to remove as many infected leaves and fruits that you can and spray the heck out of the plants, and my choice would be Daconil as being THE most effective antifungal, but the choice is yours. And there's no harm alternating that with Mancozeb or whatever.

As Mancozeb has a warning that you must wait 10 days after spraying to pick the fruit, while Daconil says "next day", I think I will go the Daconil route. Of course, I will wait longer after spraying to harvest from these plants, but it just appears that Daconil is less of an issue in this regard.

Thanks!

Raybo

[amideutch]

Ray what has been the dosage rate you have been using with the EXEL LG. You can go up to 4 tablespoons per gallon. Ami

[rnewste]

Originally Posted by amideutch

Ray what has been the dosage rate you have been using with the EXEL LG. You can go up to 4 tablespoons per gallon. Ami

Ami,

On my spraying 3 days ago, I used 4.5 tablespoons per gallon of water. No effects as of today. Guess I need to bring out the "heavy weapons". Fortunately, it is only on 3 of my 32 plants - - so far).

Raybo

[amideutch]

Ray; Something I came across. Check out "Onion Bulb Extract 3". Might want to do a test on an infected plant and see what happens. I'm definately going to get you some azoxystrobin to test for next season. Ami

http://www.oisat.org/control_methods...rol/onion.html