Thursday 14 July 2016

Tomato progress report

The tomatoes are surviving. I won't say that they have "shrugged off" the residual weedkiller contamination, but they have grown through it. Only one plant is looking really bad at present. It's the "Stupice" one, seen in this photo nearest the camera:



Despite the severe damage to its leaves, this plant is still producing fruits that look normal.




Almost all the big tomato plants have exhibited a certain amount of leaf-curl and distortion, but some have fared better than others. In this next photo, notice how the plant in the centre looks very normal, whereas the others ("Black from Tula", left, and "Caspian Pink", right) have  a lot of damage, particularly leaf-roll on the lower leaves.




The centre plant is "Primabella", one of the new blight-resistant varieties. Maybe it resists weedkiller better too? My only complaint about this variety is that it took ages to produce any flowers. The first truss is about halfway up the plant. For that reason I'm letting one of the big side-shoots develop when I would normally pinch it out. This might boost the amount of fruit I get from it.


Here's a contrast in styles: the little one on the left is "Cherokee Purple", and the one on the right is "Costoluto Fiorentino". The "Cherokee Purple" is very much smaller than normal (I've grown it for the last 3 years), but curiously it is one of the most advanced in terms of its fruit - you can see a couple of big ones on it already. The "Costoluto Fiorentino" is completely different - a big, strong plant with masses of leaves, but the fruit is only just beginning to set.


In the centre of this next photo is "Ferline", another regular of mine because of its blight-resistant qualities. Ironically it has been one of the worst hit by the weedkiller problem. You can perhaps see that even the new leaves appearing at the top of the plant are twisted and curled-in.




A couple of days ago I thought I detected the first signs of blight on my "Maskotka" bush tomatoes.


"Maskotka" - gone wild!

Can you see the dark patches on the stems in the photo below? This is what I suspect(ed) of being the signs of blight. I'm still not sure, and the leaves, though pale, look OK still. It may just be natural colouration.




Anyway, it seems highly likely that blight will strike at some stage, and probably soon, judging by the warm humid weather, so I have taken a few precautions.


First, I have moved one of my two "Ferline" plants (blight-resistant, allegedly), round to the front of the house. My reasoning is that if the plants at the back of the house get hit by blight, this one might just escape it. Furthermore, its relocation has allowed me to move the other plants just a little further apart, which will improve air-flow.


Second, I have put back into the plastic greenhouses the plants I am growing from side-shoot cuttings. They are not huge yet, so they fit well enough:




My reasoning here is that since the spores of blight are air-borne, the greenhouses may shield the plants from them to a certain extent. Not completely of course, because if I close the flaps on the greenhouses they get very hot indeed - 45C on a sunny day. If the big 1st-generation plants succumb to blight, maybe these little ones will develop in time to give me at least a small late-season harvest? I'm still not sure they will develop quickly enough to produce ripe fruit before Autumn.


There's little else I can do at this stage but wait and see. If I notice signs of blight I will try to minimise the damage / slow its effect by cutting off affected foliage, but once blight gets into the stem of a plant it's pretty much doomed. Even the ones deemed to be blight-resistant will succumb if infected, just not as quickly!

11 comments:

  1. Respectfully, I do hope you consider tossing all of the fruit and produce grown in this contaminated soil. If the poison --and that's what herbicides are, chemicals designed expressly to kill cells-- is in the leaf, it's also in the fruit or vegetables. This is baaaad, baaaad stuff.

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    1. Interesting point. A brief read-up suggests that the weed killer binds tightly to Lignin (in cell walls) and passes through animals (horses etc) undigested. Wikipedia suggests that Lignin can't be digested by animals (and I would guess also humans but I don't know). It is more than probably that when it is in a tomato it is already attached to Lignin and won't act as a poison to humans. As a weed killer out of the bottle it probably is a poison as it would attach to your cell walls (if we have Lignin in our cells) but since we would be eating it in a different form, having gone through a plant, I wouldn't have an issue with eating the fruit. It must be in such tiny quantities if it gets into fruit. I guess if the fruit is deformed, then probably don't eat.

      Worth finding out more though, because I certainly don't know any more than a guess...

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    2. https://www.rhs.org.uk/advice/profile?PID=477 says

      "The Chemicals Regulation Directorate (CRD) has investigated the risk to human health and concluded that produce from affected land is safe to eat."

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    3. Yes, I have seen this. I don't always believe what I read, especially if I think vested interest is involved - e.g. if (when) Dow Agrochemicals say it is not dangerous... But on balance I think it is OK to eat the fruit from my tomatoes.

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    4. Just to clear things up, and I'm not a biologist (chemist) but lignin is an organic polymer, part of the structure of the plants vascular system (think wood). If the herbicide is tightly bound to lignin it's probably not getting into the fruit. From what I have read fruits are selective about what chemicals they allow into them. I would be much more concerned about eating leafy vegetables grown in contaminated soil. Plants have cell walls, little boxes surrounding the cells, animal cells don't have cell walls or lignin. More than likely the herbicide does not make it through the digestive system.

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    5. Thanks, Mike, that's reassuring!

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    6. Just to add to this discussion. Cattle browse on grass that has been sprayed with hormone based herbicide and we eat the beef from the cattle and also drink the milk. This has been deemed say by the powers that be.

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  2. Hi Mark, I'm afraid my Mastkotka have all just been chucked - they started with the dark stem bits and succumbed to the blight shortly afterwards. Of my nine outside plants, only three are left and I don't have high hopes for those. Hey ho. Fortunately, there are six others in the greenhouse going strong.

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    1. I'm watching mine VERY carefully! They do have dark stems, but no signs of blight on leaves, so it may just be natural colouring. I hope so!

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  3. Do you think that the difference in the level of damage from the herbicide residue could be due to the amount of contamination present in that particular batch of compost rather than resistance by the variety of tomato plant?

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    1. It could be, sure. I've no way of telling though. This year I am religiously segregating material from any affected plants (toms and beans mostly) and putting it into sacks for disposal at the tip.

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