Author Topic: Blight (Read 3043 times)

mat · « **on:** January 15, 2006, 13:05:04 »

Has anyone had any success with covering potatoes (or tomatos) with polythene (or anything else) to protect against blight? (i.e to try and keep them dry) I have found a couple of old posts by people who mentioned they were trying it, but not found any results...

I'd rather not spray my food with a heavy metal (copper...)

If you have had any success, what have you used?

cheers
mat

Jesse · « **Reply #1 on:** January 15, 2006, 21:13:02 »

There was an article in KG magazine last year about an Italian chap (I think he was italian) who grows his tomatoes under a covered structure and said it prevented blight, did you see the article?

mat · « **Reply #2 on:** January 15, 2006, 23:09:16 »

I'll look for it. There were a few copies that for various reasons, I didn't get; I hope it wasn't in one of those! If I can't find it, the next time I am at Wisley, I will look through their archive.

mat

Jesse · « **Reply #3 on:** January 16, 2006, 09:56:00 »

If you can't find it let me know and I'll see if I can find and photograph my copy and post it somewhere for you to look at.

Doris_Pinks · « **Reply #4 on:** January 16, 2006, 12:06:10 »

EJ had sucess, Ava made her some kind of structure to protect her tommies. EJ can you post a pic so we can see it, would like to try and save my toms this year and actually get some edible ones from the plot before the blight hits! ;D
Mat Ferline did OK for me, they were the last to get blighted!

derbex · « **Reply #5 on:** January 16, 2006, 14:48:21 »

Bob F. had a setup a bit like a goal -with polythene as the netting- and the plants growing under it in the goal. I imagine that you'd need to position it for the prevailing wind to get the best out of it.

Jeremy

Doris_Pinks · « **Reply #6 on:** January 16, 2006, 15:31:41 »

Jeremy, wouldn't the blight just blow in through the goalmouth though? Or is it more a rain issue with blight?
See me old brain cells are trying to dredge up how blight works! ;D

derbex · « **Reply #7 on:** January 16, 2006, 16:05:24 »

It's certainly not guaranteed, even if it is just rain the wind might blow the other way (I grow my toms in the greenhouse for this reason. The book happens to be by my PC and he thinks that the plastic will keep off the rain (which runs down to the base of the plants) and blight spores. I think the plants are led up strings close under the sheeting.

I've never tried it but could be tempted one year.

Funny stuff though blight, I've grown outdoor toms in the garden with no problem, but the allotments (not a mile away) seem to suffer.

Jeremy

Doris_Pinks · « **Reply #8 on:** January 16, 2006, 18:33:40 »

Jeremy for the past 2 years I have somehow had it in the greenhouse too! :o :o :'( And that is with me being meticulous about washing down sterilising etc.
Our lotties are rife with it too, what a pain it is!

mat · « **Reply #9 on:** January 16, 2006, 18:59:26 »

okay, so it sounds like I need to build some kind of tall tunnel for them, with ventilation at the top, but this is not guarateed, but may help! I will have a think of a design...

oh, how tall do potato plants grow on average??? I thought they would be short, but something that I read recently made me think I am wrong and that they grow tall... I need to know how hight the tunnel needs to be (allowing ventilation space above plants, so condensation doesn't drip onto them...

mat

Jesse · « **Reply #10 on:** January 16, 2006, 20:16:07 »

I think it depends on the variety mat, mine were about 3ft high but I've seen others taller than that.

Doris_Pinks · « **Reply #11 on:** January 16, 2006, 22:29:59 »

opps sorry Mat I should have clarified, I was talking tomatoes! :-[

redimp · « **Reply #12 on:** January 16, 2006, 22:37:09 »

I am sure DP that it will work for potatoes as well - just on a much larger scale which means that watering will also have to be on a much larger scale and to the base of the plants as well. Something else to factor in mat.

Doris_Pinks · « **Reply #13 on:** January 16, 2006, 22:49:32 »

That would be a big bloody goal RC!!! No one would miss! ;D

redimp · « **Reply #14 on:** January 18, 2006, 21:03:11 »

We shall have to install a portable one at Sincil bank then DP so that it too can swap ends at half time. I have though about taking them a barn door to practice with. ;D

Doris_Pinks · « **Reply #15 on:** January 19, 2006, 23:10:40 »

;D ;D ;D

kenkew · « **Reply #16 on:** January 20, 2006, 12:24:22 »

I made 2 structures for tommy's last year. The first pic is just a flimsy affair to keep rain to a minimum. This one got sun for about 40% of the day. Most of the tom's got blight.
The second pic is a better shelter with just the front open which I sometimes put a fine mesh net over. This one got sun all day. No blight at all.

jennym · « **Reply #17 on:** January 20, 2006, 19:29:59 »

Last year, and before, I've noticed that the tomatoes grown which had some shelter from wind by being in the lea of taller plants and structures didn't get hit by the blight until much later that ones that weren't. Some didn't get affected at all. All were grown outside, so all got rained on.
The plots to the south of mine got blight before mine did.
I deduce from this that the spores travel in the wind? maybe rain too, but it definitely seems like there is a wind factor to me.

redimp · « **Reply #18 on:** January 20, 2006, 19:51:55 »

I think the spores travel on the wind and get stuck to wet foliage rather than come down with the rain.

john_miller · « **Reply #19 on:** January 28, 2006, 13:10:19 »

Quote from: jennym on January 20, 2006, 19:29:59

Last year, and before, I've noticed that the tomatoes grown which had some shelter from wind by being in the lea of taller plants and structures didn't get hit by the blight until much later that ones that weren't. Some didn't get affected at all. All were grown outside, so all got rained on.
The plots to the south of mine got blight before mine did.
I deduce from this that the spores travel in the wind? maybe rain too, but it definitely seems like there is a wind factor to me.

Correct, Jenny. Rain actually suppresses blight. The spores need dry, buoyant air to spread. Rain drops will physically knock the spores to the ground where they will die- some fungi are able to sense whether it is raining or not and will not release their spores until it stops because of this. Blight may or may not be able to do this (I've never seen it mentioned anywhere).
If a fungal spore lands on a host leaf and then it rains it may also get washed off before it has a chance to establish. All that blight needs to establish is a thin film of moisture on the leaf that will quickly allow the mycelium to grow into the leaf tissue and take hold. The optimum conditions for this to happen are either warm days and cool nights, promoting dew, or the period after rain (or manual watering- which is why watering in the morning is best) when the foliage is still wet.
I regularly grow speciality tomatoes in completely enclosed greenhouses next to field tomatoes. I have never had to spray in the greenhouse but the outdoor ones are always on a fixed 10 spraying schedule with copper.

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Author Topic: Blight (Read 3043 times)