Tomatoes rotting


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We planted a few tomatoes some months ago and even used bug spray back in June. The lants were booming and there were a lot of tomatoes coming in.
However, starting in Aug the plants started going black, leaves startedto rot and some of the tomatoes going black.
 

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The conditions for outside tomatoes in some broad areas have been poor this year. I have noticed not only the usual pathogenic fungi in my garden, but also have discovered that other immediate cousins of those fungi (such as my usual septoria leaf spot) have also shown up. I had to up the spraying, both in the antifungal and fertilizer/insecticide areas to return to a more expected growth pattern and result.
 
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What is shown in the pictures is called Late Blight and unless you have been spraying copper throughout the season you may as well pull them up and work on your soil for your next crop of vegetables. There is no cure.
 
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What is late blight a result of? Is it a fungal infection? Are there organic sprays to help prevent it?

Thank you! Complete newbie trying to understand as much as I can :)
 
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Copy pasta from https://extension.umn.edu/diseases/late-blight

"Late blight is caused by the oomycete Phytophthora infestans. Oomycetes are fungus-like organisms also called water molds, but they are not true fungi.

There are many different strains of P. infestans. These are called clonal lineages and designated by a number code (i.e. US-23). Many clonal lineages affect both tomato and potato, but some lineages are specific to one host or the other."

Like most fungal attacks, by the time you see it, you missed your chance to stop the attack, and are only able to help the plant or future growth.

Organic growers have a tough time with this. A product that the plant thinks is phosporus but is actually salts of phosporous acid is used as a systemic defense against Phytophthora. Agri-Fos is one brand name. I am not clear whether it is considered organic or not.
 
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What is late blight a result of? Is it a fungal infection? Are there organic sprays to help prevent it?

Thank you! Complete newbie trying to understand as much as I can :)
In reality there just isn't much a gardener can do about late blight. Basically, it is up to Mother Nature as to whether one will have the disease or not. This disease appears during extended cool, damp, foggy, misty, rainy, humid weather, usually late in the season. Thus the name. It does not overwinter in the soil but the spores drift with the wind. Basic gardening techniques of cleanliness is about the best thing one can do. Copper sprays applied very early have some effect but IMO as soon as the plant shows any symptoms, pull and burn the plant. The first symptoms look like water-soaked spots on the leaf edges and on the bottom of the leaves, usually close to the bottom of the plant. Sort of like if you crushed the leaf between your fingers. Anyway, the disease does not happen every year. Try to plant only late blight-resistant plants and seeds.
 
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Warning long post!

Some following words are a struggle, but they make GREAT google search terms when you are struggling with a garden problem like how to impact this disease organically.

We have an easier time fighting off attacks that are on the outside of a plant. This late blight has the ability to get inside and without something systemic to stop it, the party is over quickly. This is why I will pull out agri-fos when it gets bad. I have not found better. This family of pathogens even attacks fish. I was fascinated to read the following from the Berkeley website:

Water molds were once thought to be fungi.​

The Oomycota were once classified as fungi, because of their filamentous growth, and because they feed on decaying matter like fungi. The cell wall of oomycetes, however, is not composed of chitin, as in the fungi, but is made up of a mix of cellulosic compounds and glycan. The nuclei within the filaments are diploid, with two sets of genetic information, not haploid as in the fungi.

The ultrastructure, biochemistry, and molecular sequences of these organisms indicate that they belong with the Chromista. The free-swimming spores which are produced bear two dissimilar flagella, one with mastigonemes; this feature is common in the chromists, as is the presence of the chemical mycolaminarin, an energy storage molecule similar to those found in kelps and diatoms. Thus, although oomycetes are in the minority as heterotrophic chromists, they quite definitely belong with these other chromist groups.




Parasitic water molds damage fish and many crop plants.​

Some water molds are parasites on other organisms; they may grow on the scales or eggs of fish, or on amphibians. The water mold Saprolegnia causes lesions on fish which cause problems when the water is rather stagnant, as in aquaria or fish farms, or at high population densities, such as when salmon swim upstream to spawn. Other species of Saprolegnia are parasitic on aquatic invertebrates such as rotifers, nematodes, and arthropods, and on diatoms.

Their greatest impact on humans, however, comes from the many species of water mold which are parasites on flowering plants. These include root rotting fungi, seedling dampening mold, blister rusts, white rusts (Albugo), and the downy mildews that affect grapes, lettuce, corn, cabbage, and many other crop plants. Two of these disease-causing chromists have had a major impact on world history.

The first of these is Phytophthora infestans, the organism which causes late blight of potato. The potato is native to North America, but once it was introduced to Europe, it quickly became an important food crop. Late blight did not follow its host plant across the Atlantic until much later; the disease organism grows into the stem and leaf tissues, causing death, and may also infest the tubers, which are the part of the plant that is eaten. The disease spreads rapidly under cool and damp conditions, which are common in western Europe. In one week during the summer of 1846, this diease wiped out almost the entire potato crop of Ireland, a crop which was the primary food of the poor at that time. Nearly a million Irish died in the Great Famine, and an additional one-and-a-half million emigrated to other countries, including America. Thus, if you are an American with Irish ancestry, it was probably the oomycetes that brought your family here. Other species of Phytophthora destroy eucalyptus, avocado, pineapples, and other tropical crop plants.

The other oomycete which has severely impacted recent history is pictured at right -- Plasmopara viticola, the downy mildew of grapes. It also is a native of North America, but in the late 1870s was accidentally introduced to Europe. At the time, the French wine industry was concerned over a massive aphid infestation, and so brought resistant vine strains over from America to breed them into their own grapes. When these American stocks arrived, they also brought the downy mildew, which almost wiped out the entire French wine industry. The industry was saved by the serendipitous discovery of Bordeaux mixture, a mixture of lime and copper sulfate, which brought the disease under control when applied to the leaves of the plants. This discovery is also important for being the first known fungicide, and in fact the first chemical used to control a plant disease.
 
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Wow! Thank you @DirtMechanic & @Chuck! I’m currently reading “The Botanical Bible,” & trying to refresh my knowledge of the one botany class I took in college… Understanding the science & history behind different garden problems is invaluable to me. Much, much appreciated!
 
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Check roots for Root Knot Nematodes. Those are easy to spot.
When I pulled up my spring tomatoes I checked because we have RKN. I thought it significant that I did not see the knots. I speculate that the wetness hindered them in some way. The roots were distinctively clean.
 
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I pulled out all but one of the of the tomatoe plants; thats a couple of Kgs gone to waste.
But just now, the nearby young fruit trees have started to suffer with leaves going yellow. Could this be blight as well?
 
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I pulled out all but one of the of the tomatoe plants; thats a couple of Kgs gone to waste.
But just now, the nearby young fruit trees have started to suffer with leaves going yellow. Could this be blight as well?
Fall is getting near so your fruit tree leaves will start to change colors before they all fall off for the winter. Nothing to worry about.
 

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