London (change)
14 messages
20/09/2012 at 22:41

Hi there,

Its my first time growing tomatoes in the greenhouse. Almost all the tomatoes on the lowest trusses have some kind of rot / infection. See pic below

 I'd love to know

  • what's wrong
  • how to avoid it next year
  • Can I compost them, or is it in the rcycle bin?
Many thanks in advance for your help   James
20/09/2012 at 23:07
Its a type of blight. A lot of people have had the same issue. It may also be affecting the leaves and stem too (turns brown) if caught early enough you can treat the plants with an appropriate fungicide. However based on your picture its probably a bit late. Best to pull all the affected plants out and either burn it or send to tip
21/09/2012 at 09:10

Thanks for your reply. Strange that I've had the lowest tomatoes doing this for 3 to 4 weeks now, but remainder (75%) and plants all healthy. If it is blight what are the ramifications for the soil (they are planted into the ground, not gowbags)?


Again, many thanks for any help



21/09/2012 at 09:38

James, are there absolutely no signs of disease on the foliage or stems/branches?

21/09/2012 at 11:29

No - its only on the lowest fruit. The rest of the toatoes are all slowly ripening / still growing. My only thought was that these tomatoes would have been the only ones to have been splashed by me watering, so I wondered if that could somehow be the cause (the waterbutt water certainly isn't drinkable!), or maybe splash up from the earth?

Here's the proof





21/09/2012 at 12:53

Mmmmm. If it were one of the common fungal or bacterial diseases there would be symptoms elsewhere. It looks a wee bit like Late Blight -

- but it can't be with no other symptoms. And if it were Late Blight it would have demolished the plants within your two or three week time frame.

Any chance of it being fertiliser burn?

Nice toms, though, and I like your gap between the lowest foliage and the soil. Good housekeeping!

21/09/2012 at 14:11

No blight in the greenhouse so far, but the plants on the allotments succomed weeks ago.  Something to do with growing them alongside potatoes which also have succomed to blight.

21/09/2012 at 14:52

I agree it does look a bit like the photo of late blight. Maybe I've just been lucky - I've removed the fruit as soon as I noticed a problem.

I have used liquid tomato fertiliser - that could be the issue and would explain why its only the lower ones where I watered

21/09/2012 at 14:54

Gary, both Early and Late Blight affect spuds and toms so, if the spores are around, they are going to spread.

21/09/2012 at 14:58
Jammy2 wrote (see)

I agree it does look a bit like the photo of late blight. Maybe I've just been lucky - I've removed the fruit as soon as I noticed a problem.

I have used liquid tomato fertiliser - that could be the issue and would explain why its only the lower ones where I watered

Late Blight usually manifests on leaves and branches/stems before it spreads to the fruit. If it's the fruit alone that's damaged, I suspect something else has impacted.

21/09/2012 at 15:16
Agree with all of the above. Most forms of blight you Will see affect the leaves then spreading to fruits and stems.
If it doesnt spread put it down to water or chemical scorching. Which would be unrelated to soil issues. However if there is any further spread it would most likely be blight related. And would suggest changing the soil or not using the greenhouse for toms (or spuds) for a couple of seasons
21/09/2012 at 15:30

If it's a blight - let's call it fungal - issue, it has no devastating impact on the soil. If Late Blight, the spores don't live on in soil. If Early Blight, much more common, spores can have fallen to the soil. Turn the soil over and bury them. Buried, they're harmless. Ditto the other fungal diseases. A scrub of the greenhouse with a 1:10 bleach solution will deal with any lingering nasties.

Given reasonable precautions, reinfection from spores from the previous season is pretty rare. Most infections are new ones. Fresh spores arrive every season. They travel on the breeze. There's really no avoiding them.

21/09/2012 at 16:43

This looks very much like blight to me, don't forget we've just had the wettest summer ever which favours blight spread. Unusual though that there are no lesions on the foilage. Best to remove infected fruit and ' infected 'whole' branches and hope for the rest to ripen. Too much humidity in glass house will favour spread of spores but it has been so wet with very early dews and dusk dews. Mine in soil in the garden have a few infected plants - those in pots on a South facing wall seem to be OK, better pollination and fruit set -  a long time to ripen though - may be the year for Tom Chutney????

15/11/2012 at 14:38

I agree with the above. Looks like Late Blight.

Leaves infected with Late Blight develop water-soaked patches that turn brown. In humid weather there may be a white, downy growth on spots. Over time the spots expand rapidly and become brown to purplish- black as tissue dies. Plant may look “frosted”.

Fruits can be affected at any stage. Large irregular, rough, brown-green lesions can be found on the fruit. The disease (which is devastating
in potatoes) can also cause severe losses in tomatoes when conditions are favourable (cool, wet weather) resulting in severe defoliation. 

For more info check out this site: Best Juicy Tomatoes

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