Is It Blight?

[SarzWix]

I've moved this thread back to Vegging Out for the time being. If you think you might have blight, check out the pics and links on the first couple of pages before you panic. Also, blight testing kits are available from a numbet of seed potato retailers such as JBA Seed Potatoes.

[VirginVegGrower]

Thanks, I thought I'd got it, but doesn't look like it.

[poly]

I found Late blight on some of my potatoes last monday I'm in South West Wales.
Only in one bed so far, I'm hoping I spotted it and removed the foliage quickly enough to stop it spreading to the main potatoes and my tomatoes.

[ItsEssexRob]

I recently bought a cherry tomato plant from a Wyevale and since learned that the others around it had this disease that looks exactly like this when I type Tom blight into google images.

Google Image Result for http://nuwildroots.files.wordpress.com/2010/06/septoria-leaf-spot2-copy.jpg.

I cant see anything major on my plant yet but I isolated it from my GH tomatoes and others just in case.

Can it affect anything other than Toms and Pots at all as I have masses of Chillis and Peppers?

Also I found a suibstance called Dithane avialable on ebay but it says it was taken off the shelves a few years ago. Anyone know why? Is it safe to use if I did get blight?


Thanks

[snohare]

Anyone know why? Is it safe to use if I did get blight?

Here you go, have a look.
LD50 is the dose at which 50% of the test animals died, a teratogen is something which causes fetal abnormalities - eg spina bifida, a mutagen causes changes to DNA which may lead to cancer or other development disorders in successive generations.

http://http://pmep.cce.cornell.edu/profiles/extoxnet/haloxyfop-methylparathion/mancozeb-ext.html


Basically, most fungicides have been removed from availability for use under most circumstances due to toxicity concerns. Partly this is because many of them are endocrine disruptors; the endocrine system in effect regulates what chemical reactions go on in the body, and these disruptors may affect many different species, so you can imagine that the potential for environmental damage is great. Fish changing sex and tadpoles with extra limbs are examples of this phenomenon, but of equal concern is the potential effects on fertility and the ability to cause epigenetic changes - changing the way genes switch on and off in offspring. (Diabetes is sometimes an example of this, as a result of the effects of malnutrition in the parents. Some autistic spectrum disorders may also result from epigenetic factors.) The fact that many chemicals may be synergistic is also relevant - in other words, being exposed to a cocktail of say three chemicals, may multiply the damage each one could cause individually, rather than merely adding to it. As we are exposed to a large number of chemicals nowadays, this is not good !
The recent ban has been of great concern to the agricultural and horticultural trades, as there are now many fungal diseases for which there are few if any remedies. Furthermore, fungal diseases are forecast to become more of a problem as climate change progresses - a convention of biological scientists came to the conclusion some time ago that the 21st Century was going to be "the century of the mould".
So - dithane works, it is still used commercially in the UK. The only question really is, how lucky do you feel, were you planning on having a family...?

[dominic10]

We have blight in our area and there was a notice on our allotment notice board saying to be on the look out for it. Later in the day it was discovered on one of the plots. We were told we would be OK as we are 'downwind' of the affected plot but we'll see. We have had a Smiths period in our locality apparently. But the site notice board warned of avoiding rain on tomato plants - does anyone know why? The person who has the blight seemed to know quite a bit about how to deal with blight but didn't know about why to avoid the rain with tomato plants.

[taff]

same reason as with potatoes. blight spreads by spores, spread by wind and rain.

[dominic10]

same reason as with potatoes. blight spreads by spores, spread by wind and rain.

Thanks Taff - I've been reading more about the causes of blight on the net. What I was concerned about also was watering my plants from the water butt i.e. rainwater but I have now found a site which advises watering with tap water. I knew to avoid watering the leaves but as it has rained today I will just have to wait and see. My tomatoes are outdoors. I can't find information about whether the spores stay active in the water butt but am aware that damp weather encourages blight. I appreciate the rain may wash the spores onto plants but the mating habits of the spores themselves is way beyond my biological ability.

[taff]

if you can avoid splashing water onto the plant, there's no reason not to use rainwater. the spores have to be damp at the right temperature to infect a plant, so if you keep the water off the plant, you're more likely to avoid it.

[ItsEssexRob]

I keep my GH flap open to avoid it getitng too humid inside and to prevent Botyritis. Does this increase the likelyhood my Toms would catch blight though? Also, what is a Smiths period and how do I know if we have one?

Thanks.

[dominic10]

Also, what is a Smiths period and how do I know if we have one?

Thanks.

This link should help Blightwatch.co.uk - the essential service for professional potato growers

[Alison]

To be honest I keep meaning to unsubscribe to the blightwatch site as it just worries me and I'm not going to spray anyway as it's horrible stuff so I think I might be better in ignorance as not all Smiths periods lead to blight.

[FlawlessVictory]

Is this blight

Hi I'm new to the boards and have just been reading rather than contributing but I have come across a problem and I was just wondering if my tomatoes have blight and if infact I can salvage anything from them.

[VirginVegGrower]

Five out of about thirty plants in the polytunnel have blight. All pulled out. This is because my eye was off the ball. Fingers crossed for the GH ones.

Edited because I think in my confused state I have just uprooted five tomato plants with magnesium deficiency instead. Brown spots not black

[binley100]

Noticed that some of my tattie leaves are yellowing the same as some of my toms so did a bit of hunting ..found this site with pictures and it looks like magnesium deficiency again........From what I've read the heavy rain has battered the soil making it hard for the plants to take up the mineral. Guess the tatties will be having an epsom salt spray as well.
Color Pictures of Mineral Deficiencies in Potato Plants