Tomato blight

[littlemoney]

One of outdoor tomato plants has brown on the stem and another has brown on the central stem of the leaf. Is this blight and what should I do please. I only have 6 plants, am I likely to lose them all of can I do something to delay the progress so I can get some of the tomatos ripe. Thanks.

[burnie]

A picture of the problem would help us

[ameno]

A picture would help to give a definite diagnosis, however if you have brown patches on the stems then it almost certainly is blight.

You can delay its spread somewhat by removing all infected leaves and stems (whole plants if the stems are infected near the ground), however unless you are growing blight resistant varieties then this is only going to keep it at bay for maybe another two or three weeks at most. So unless your tomatoes are nearly ripe already, you are unlikely to get any ripe fruit.
You can compost blighted material, as blight fungus and spores cannot survive more than a few weeks without a living host. You need to make sure you put them in a lidded compost bin, though, so that the spores don't spread around and infect more plants this summer, before the spores die.

There are recipes you can use with green tomatoes. I made soup from some of mine yesterday. It tastes just like normal tomato soup, really, only a bit less sweet and a bit more sour.

[goosander]

Would i be safe to say that if the stems have brown on them it is blight and if no brown then no blight.
Have been and given all my plants a dose of Epson salts dissolved in water but see no change. How soon would you expect to see a change in the leaves.
Thanks.
Bob.

[littlemoney]

3 of my 6 plants have brown stems. one plant the brown is half way up so as suggested I have cut the stem below the brown. The other two the brown is near the bottom, so no hope there. Also as advised I have removed affected leaves.

If I leave the two plants with brown stems planted in the garden will this mean the blight will spread quicker or do I have nothing to loose and may get a few tomatos for all my had work as the spread is inevitable. Thanks

[ameno]

3 of my 6 plants have brown stems. one plant the brown is half way up so as suggested I have cut the stem below the brown. The other two the brown is near the bottom, so no hope there. Also as advised I have removed affected leaves.

If I leave the two plants with brown stems planted in the garden will this mean the blight will spread quicker or do I have nothing to loose and may get a few tomatos for all my had work as the spread is inevitable. Thanks

If you leave infected plants then it will potentially spread quicker, but remember that it only affects tomatoes and potatoes, so if you're down to your last few plants and they are all infected then it may be worth just stripping all of the infected leaves and then keeping your fingers crossed, as at that point you don't really have anything to lose. Just be sure to remove any infected fruit as they arise, too.

[ameno]

Would i be safe to say that if the stems have brown on them it is blight and if no brown then no blight.
Have been and given all my plants a dose of Epson salts dissolved in water but see no change. How soon would you expect to see a change in the leaves.
Thanks.
Bob.

If the stems are brown/black then it is almost certainly blight, yes.
However, just because the stems are not brown, doesn't necessarily mean it is not blight. Stems tend to get infected a bit later than leaves, so it could just be early stages of blight on the leaves. Or, it could instead be something less harmful, like a nutrient deficiency or early blight (a completely unrelated and far less harmful disease).

Late blight (the devastating one) is the only one which will infect stems, so if you have infected stems then it is indeed a sure identifier. On leaves, late blight tends to be quite dark (dark brown or grey, quite often grey on leaves, actually), usually the patches are wet-looking (unlike early blight or nutrient deficiencies, which tend to produce dry brown patches), in damp conditions they may have white fuzz on the underside (the fungal spores), and the dark patches spread very quickly.

[goosander]

Thanks for that Ameno. Had blight [brown stems] last season and cleaned the greenhouse and fumigated it with smoke candles to try and get rid of it.
Bob.

[ameno]

Thanks for that Ameno. Had blight [brown stems] last season and cleaned the greenhouse and fumigated it with smoke candles to try and get rid of it.
Bob.

That's actually completely unnecessary.
The fungus which causes blight is not terribly hardy. Both the living fungus itself and the spores cannot survive more than a couple of weeks, a month at the very outside, without a living host. So it's perfectly safe just to clear up all the debris and compost it; it won't survive.

The way it usually overwinters is on infected potato tubers. The tubers are obviously still alive, and low temperatures make the fungus in them go dormant, so they don't rot over winter. Then they start growing again the next spring, the plant gets blight almost immediately, and it then spreads to to other plants that year.

[goosander]

[QUOTE=ameno;n2530874]

That's actually completely unnecessary.
The fungus which causes blight is not terribly hardy. Both the living fungus itself and the spores cannot survive more than a couple of weeks, a month at the very outside, without a living host. So it's perfectly safe just to clear up all the debris and compost it; it won't survive.

Thought i would just take no chances not knowing much about greenhouse pests.
Thanks for your help. Better peace of mind for me now,
Bob.

[Plot70]

It is worth burning the infected plants if there are others near by that are still healthy.

[ameno]

It is worth burning the infected plants if there are others near by that are still healthy.

That's overkill. And indeed could do more harm than good, as the updrafts caused by the fire could just spread the spores further before the heat is able to kill them.
Far better just to compost them. As long as you have a lidded bin then any spores will be contained an unable to escape to infect other plants. Within a few weeks, the plants will have rotted to sludge, at which point the fungus and its spores should be dead, too
Or if you're that worried, there is always the Council green waste collection.

[Plot70]

The green bin gets tipped into a truck throwing spores all over the place.
If I was going to do anything else it would be under the brassica patch below root level where the material would stay for an entire growing season undisturbed.
The fire is in a steel cylinder that glows red hot with dry wood offcuts in it. It gets a lot hotter than those dusty bin things with a little chimney on the top.

[ameno]

The green bin gets tipped into a truck throwing spores all over the place.
If I was going to do anything else it would be under the brassica patch below root level where the material would stay for an entire growing season undisturbed.
The fire is in a steel cylinder that glows red hot with dry wood offcuts in it. It gets a lot hotter than those dusty bin things with a little chimney on the top.

The problem is that the spores are incredibly light, so updrafts of hot air from the fire are liable to send a lot of them aloft without you even realising it as you feed the plants into the fire.
It's also just redundant. Composting them in a lidded bin is more than sufficient.

[Plot70]

Well the kohlrabi is almost ready and that bed will have room for the waste.
The radiant heat is more of a problem with other plants about. The burning space is limited right now.