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15 messages
13/09/2012 at 12:16

Aaggh. Newbie here growing greenhouse Alicante tomato's. Whole branches of each of my plants are dying and the ripening friut is rotting. Obviously no good this year but any ideas on how I can prevent further happenings pls.

13/09/2012 at 13:14

Any chance of a photo, Colin? It sounds like a fungal problem. If the spread from foliage to stems to fruit has been rapid, it could be Late Blight. If not rapid, it could be a number of things. There are even fungal problems specific to greenhouses that are rarely found with outdoor toms.

Anyway, given that it's probably fungal, you can never guarantee against it ever happening. Fungal spores are airborne, they travel on the breeze, they're everywhere in the air, and invisible to the naked eye.

One option is preventive spraying, which means spraying before the spores arrive. Once they have arrived - when the symptoms are starting to show - it's too late. It means spraying about once a week from not long after the toms are planted out.

If you don't fancy spraying, you have to concentrate on a housekeeping routine that aims to minimise the fungal spores' chances of getting a grip.

In a greenhouse, ensure as much air circulation as you possibly can. The closed environment can be an incubator for disease.

Keep as much space between plants as you can for air circulation purposes.

Try to avoid great clumps of dense foliage developing on plants by judicious pruning of excess foliage and branches. Again, for air circulation purposes.

Keep a gap of at least a foot between the lowest foliage and the soil. Fungal spores can and will fall from the foliage to the soil and can be splashed back up again when watering causing re-infection. The gap will help against this.

The bottom line is that you can't avoid fungal spores. All you can do is try to minimise their impact.

14/09/2012 at 06:36

Really grateful for the trouble u have taken Italophile. All relevant and useful information. Really rapid spread os symptoms but, thanks again.

14/09/2012 at 08:06

Colin, do the symptoms look like this?

http://s4.gardenersworld.com/uploads/images/original/11636.jpg?width=255&height=300&mode=max

 

http://s4.gardenersworld.com/uploads/images/original/11637.jpg?width=210&height=300&mode=max

 If so, it's Late Blight.

14/09/2012 at 12:35

Exactly like that + mouldy fruit. Sorry, new camera and haven't worked out how to load pics onto laptop

14/09/2012 at 13:14

I have found with my outdoor tomatoes that they have been much better for the last couple of years when i started using chimney pots filled with compost placed on top of the soil. So the roots can still get into the soil, but they are elevated awy from the soil.

 

14/09/2012 at 14:40
Colin7 wrote (see)

Exactly like that + mouldy fruit. Sorry, new camera and haven't worked out how to load pics onto laptop

Mouldy fruit a bit like this?

http://s4.gardenersworld.com/uploads/images/original/11642.jpg?width=259&height=194&mode=max

Late Blight is one of the ugliest, most virulent fungal diseases. It can demolish an entire tomato plant inside a week.

Sparkle - I can't picture what you're describing. The plants are planted into the chimney pots but grow down into the soil underneath?

14/09/2012 at 14:50

Think of the chimney pot as a large bottomless flower pot, filled with compost and placed on top of the soil, eventually the roots will grow through the compost into the soil beneath.

my toms in the chimney pots are taller then I am now, really good strong plants. I have now cut off the tops and all the flowers and even picked off some of the tiny toms, desperatly hoping that the trusses left on will ripen. The yeild had been well down this year as it was so cold for so long

I am still waiting for the blight to strick and feel it will be a when rather then if, (the allotment 1 mile away was devistated this year) but so far so good.

The toms just in normal pots are not nearly s healthy and might have the first signs of blight.

14/09/2012 at 16:14

Ah, now I get the picture.

The chimney-pot plants have a big advantage over those in containers. By the time they get down into the soil they've developed very good root structure. Plants in containers will always have hindered root structure. But the blight difference is a matter of luck. All plants are susceptible, no matter how they're planted.

Taking off the tops, flowers, small fruit, etc, doesn't hasten the ripening process. Ripening is purely down to temperature. Optimum ripening temperatures are anything above low-20sC. The lower you go, the longer it takes. And, as soon as the toms start to turn from their very darkest green, the plant pretty much shuts off moisture to the fruit anyway.

15/09/2012 at 14:33
Hello, I have some tomato plants with the dreaded blight next to sweetcorn which also looks sick. Please could you let me know if it is transferable to the other plants in my garden and if any blight treatments are ok for them, I know it is likely that my potatoes will succumb but am worried about courgettes and the sweetcorn. Thanks very much.
15/09/2012 at 14:58

Tomato and potato blights are transferable to each other as I understand it but not to other plants

However that is not say other plants are not susceptible to other fungal diseases-it has been yet another poor and troublesome season

Onwards and upwards

15/09/2012 at 15:55
Mia's grandma wrote (see)
Hello, I have some tomato plants with the dreaded blight next to sweetcorn which also looks sick. Please could you let me know if it is transferable to the other plants in my garden and if any blight treatments are ok for them, I know it is likely that my potatoes will succumb but am worried about courgettes and the sweetcorn. Thanks very much.

When you say "the dreaded blight" it depends exactly which fungal problem you have on the toms. It might not even be fungal. It could be bacterial. Can you post a photo?

As Geoff says, toms and spuds are both prone to a couple of the same fungal diseases. One is Late Blight. If you have Late Blight, the tomato plant will be wiped out within a week or ten days. If your plants have been coping for that or longer it's probably not Late Blight. Early Blight, another common tomato fungal problem, can also affect spuds, though, as with toms, it's nowhere near as destructive.

I've never heard of any of the tomato/potato fungal diseases affecting sweet corn. Sweet corn only has one fungal threat that I know of. It's called "smut" and you'd know whether your plants are affected. The kernels expand to three or four times their size and are a dark grey/purple colour. It looks hideous, though, in some parts of the world, it's a delicacy. I get it a lot on my sweet corn here in Italy.

In terms of dealing with your disease problem now, it's too late for prevention. Once the spores are in place, you can't kill them, per se. You can only try to minimise the impact by removing affected foliage to try to stop the spread.

 

15/09/2012 at 21:38
Thank you both for your help, I have been working today in the garden, removing the worst affected tomato plants and will have a closer look at the sweetcorn tomorrow. It is disheartening when you put so much work into growing and nurturing these plants, sometimes I wonder if it is all worth it, but I'm sure I will try again next year.
16/09/2012 at 11:37

Having done some internet research, Italophile is spot on. This is Late Blight, the same that caused the Irish potato famine in the 19c. It thrives in the damp conditions that we have experienced this year. As suggested, prevention is better than cure (If indeed there is a cure) Italophile's measures have been endorsed by a number of sites. Hope no-one has suffered as badly as I have in losing the whole crop.

16/09/2012 at 12:25

There's no cure, Colin, not just for Late Blight but for any of the other fungal diseases. Once the spores have arrived and settled in - when the symptoms are showing - you can't kill them off. The same applies to most fungal garden problems - Black Spot on roses, etc.

All you can do is try to mimimise their effects after arrival or take preventive measures - prior to their arrival - by either spraying or undertaking the basic housekeeping procedures I've mentioned here so many times.

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