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No red tomatoes?? - Is that black stem the reason? Is it too late to treat?

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--- Quote ---I find it odd that the majority of the Harbinger tomatoes are ripening with no sign of blight even though there are long black areas on the stems and no leaves left on the plant!
--- End quote ---

It seems odd but good  :happy7:

Blight came in days (maybe hours) after the worst flash downpour I've seen for years (in London). It went straight to the stems, so it was doubly bad.

Up till then I'd had maybe 5 ripe toms from 10x 2m+ outdoor plants that were loaded with ripening fruit.

I cut every blighted leaf, fruit and flower off and then tried to decide which fruits might ripen before the stem blight got to them.

I knew it was a gamble, but it paid off quite quickly when the squall was followed by some really hot weather.

The blight stopped dead, even in the stems. I managed to ripen a dozen or so fruit in the weeks of heat. when it returned it was a totally new infection, none of the original brown patches have grown even now.

Obviously you can't heat a garden to kill blight - I've written those plants off; but blight is now occasionally creeping into my polytunnel - I only have to remove leaves at the moment, but if I get stem patches I'll be tempted to apply heat to those patches - somehow - maybe flame them, maybe cauterise them, maybe a "bandage" wetted in situ with boiling water - we'll see.

If it works I might have a cure for stem patches in future - even in the garden.

Science is fun! And you often learn more from experiments that fail...


PS. I must  point out (again) that Dithane is indeed "-ghastly stuff" since all the alkylene bisdithiocarbamate fungicides taste of rotten cabbage (and have been "tested" on humans for less than 40 years).

Copper however has been tested for 180 years (since its accidental discovery - blight couldn't be found within a few miles of copper refineries).

It's not surprising that Copper isn't "ghastly" since it is absolutely essential to the mammal metabolism - pathways exist to deal with an excess (unlike zinc). The copper sulphate I buy (cheapest and most readily available) is sold as a feed supplement for animals - we don't need it as our diets are so diverse, but some animals are fed on monoculture.

Deb P:
Well my indoor toms were culled yesterday, a load of caterpillars from what I suspect it tomato moth was on almost every bit of foliage, they had eaten bits out of most of the tomatoes too, so Iíve under up with only 10 viable plants left standing, and a load of unripe fruit from the culled plantsÖ..arrrgh!
My peppers snd chillies are pants too, also attacked by caterpillars and what looks like dark brown blotches on the stems..Iím not having a very good greenhouse year this year! 🙄

This is what excess copper can do - this is nearly a century after mining stopped, and much of the landscape is still free from vegetation.

Acute copper poisoning can occur - though, as you say, the body does have mechanisms to deal with it - and copper salts as used in organic fungicides are all toxic. There's a big difference between trace element needs, see for example selenium. If LD50 calculated in rats is directly transferrable to humans (hopefully you will understand why that's (a) not always the case and (b) not calculated in humans!), about 2g of your copper sulphate could potentially kill someone of my body weight.

I don't know how that compares with Dithane but I assume that both are equally nasty, and use what I have as a last resort. As I've got Dithane, that's what the toms get. 


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