Advice on cleaning up after tomato blight

[Ellesbells]

This year my tomatoes suffered a really bad bout of tomato blight. Really. Really. Bad.

Unfortunately I wasn't able to deal with it as I was in hospital with an unforseen emergency, so I came home to a complete and utter disaster zone. Normally I would cut back lower leaves & thin everything out, but wasn't able to this year and with a combination of the weather, lack of attention and everything else going on it was a bit of a perfect storm. I've never had blight as such in the garden and now I am worried this will hang about and continue next year.

I've cleared all the plant material (all of it, every single plant was destroyed) and collected the fruit into the green bin. What do I do with the soil from the containers? Can I spread it somewhere without contamination? I'll clean all the pots with *****, but I am very concerned that any tomatoes next year will not have a hope of success!

Any help, advice or reassurance would be wonderful!

Thank you

[ameno]

You don't need to do anything. Indeed, there was never any need to destroy the infected plants in the first place. They can be safely composted. And the soil can be safely used for anything you like (although it's best not to use it for tomatoes again, not because of risk of infection but just because it won't have enough nutrient left).

Blight cannot survive for more than a few weeks without a living host. Any spores in the soil or anywhere else, along with any spores and fungus on the plant material, will be long dead by next spring.
If you are wondering how, then, blight survives from year to year, the answer is potatoes. It survives on infected potato tubers, which go through the winter as a living tuber (and thus a living host for the blight), then grows into a potato plant the next year, gets infected with blight almost immediately, then spreads it to everything else.

[Ellesbells]

Thank you Ameno for all that amazing info! My potatoes were also hit badly, but they are all out of the ground and I use a crop rotation system so they won't be in the same place next year. If i've missed any, I'll whip them out of the ground as soon as I spot them (there's always one isn't there!). It is a relief that the blight shouldn't be too bad next year, I was worried the garden would be at risk.

[Jungle Jane]

Its best to destroy the blighted plants,not in your home compost. New blight strains are found,oospores can overwinter in home composting. Info from RHS -

“The presence of new blight strains in the UK means that the pathogen now has the potential to produce resting spores (oospores) in the affected plant tissues. The oospores are released from the rotting tissues to contaminate the soil. These resting spores have yet to be found in the UK, but genetic analysis of the recent variations in blight strains occurring in potato crops in some parts of the UK suggests that they could be being produced. Little is currently known about their survival and their potential as a source of the disease, but investigations are continuing and more information is likely to become available over the next few years. However, because oospores are resilient structures, if they are produced in infected foliage it is quite possible that they will also survive many home garden composting systems. This is why it is preferable to dispose of waste from blighted crops in other ways. Municipal and commercial composting systems usually reach the very high temperatures necessary to kill oospores and other resilient pathogen propagules.”

https://www.rhs.org.uk/disease/tomat...llowing%20year.

[ameno]

It specifically says "These resting spores have yet to be found in the UK".
That advice is based entirely on speculation on the part of whoever wrote it. There is as yet no empirical evidence to support it.

If you look up the life cycle of Phytophthora infestans you will see that the requirements for producing oospores are very specific and strict, and is not something which will happen just by random chance. The organism favours asexual reproduction via zoospores, which are very short-lived.

[Jungle Jane]

It says analysis of the potato crop suggests they could be being produced. Read the whole paragraph not just the section you took out. Its not based on speculation it’s based on analysis as it says. I have been reading scientific papers about blight for about ten years,you can do whatever you choose,I’m giving help for the person who posted.

[ameno]

I did read the whole paragraph. They are saying that analysis suggests that they have the potential to be produced, however as of yet no evidence of them actually being produced has been found in the UK. At this stage, it is merely a theoretically possibility.

[Jungle Jane]

It says little is known about their potential & it says analysis shows they could be being produced. We can agree to disagree now of how we interpret the statement. Analysis shows they could be being produced not the potential,it doesn’t say that. I know what I’m reading,I understand what it says there.

[Jungle Jane]

On the Bayer crop science website they talk about oospore reproduction from the blight A1 & A2 mating types -
“In British crops, however, despite the prevalence of the A1 and A2 mating types, oospores have not yet been found. It is almost certain that they are there, but we just haven’t looked for them. There is an increasing body of evidence to show that oospores could be an important source of primary infection. In the North of Scotland, the presence of “Other” or “Miscellaneous” genotypes in Fight Against Blight reporting is evidence enough of sexual recombination occurring.”

“Each germinating oospore is genetically distinct, and such ‘re-shuffling of the genetic pack’ generates new combinations of traits. Through a process of natural selection those genotypes that are more aggressive, fitter, resistant to fungicide or more capable of overcoming host resistance than the existing pathogen population, will be more likely to spread and cause crop disease that is more difficult to manage.”
https://cropscience.bayer.co.uk/late-blight/

This further explains why it is recommended by RHS etc to destroy blighted material & use crop rotation.

[Nicos]

Thanks both of you- differing views but it’s all very helpful to other gardeners make their choice.

It’ll be really interesting to see the results of Ellesbells' growing in potentially infected soil.

Personally , I’m pretty paranoid and destroy everything, as I have enough other things in the garden which do their utmost to ruin my fruit and veggie growing. It certainly is a serious problem when it gets hold.

For those willing to risk, or feel confident they will be fine- from personal experience or otherwise, then that approach has certainly opened my eyes.

Do keep us updated Ellesbells - it’s an interesting ‘experiment’.

[Jungle Jane]

Thanks both of you- differing views but it’s all very helpful to other gardeners make their choice.

It’ll be really interesting to see the results of Ellesbells' growing in potentially infected soil.

Personally , I’m pretty paranoid and destroy everything, as I have enough other things in the garden which do their utmost to ruin my fruit and veggie growing. It certainly is a serious problem when it gets hold.

For those willing to risk, or feel confident they will be fine- from personal experience or otherwise, then that approach has certainly opened my eyes.

Do keep us updated Ellesbells - it’s an interesting ‘experiment’.

Ellesbells says they use crop rotation so won’t be in the same soil next year.

[Nicos]

^^^^ true!…I’d forgotten - thanks!