Topic: Possible potato blight- advice sought

[plot88(Cardiff)]

Hello all,
Some of you may recall my garlic panic a few months ago, well despite that, and a fierce case of rust, I pulled a fantastic crop of Garlic a few weeks ago.

That's the good news.

Panic no. 2.
My spuds are not well.

I have uploaded a series of images to my picassa web album :-

http://picasaweb.google.com/plot88/PotatoWoes?authkey=0jyhvP2x4BY

The first series show what I believe to be early potato blight on my Charlottes.

The last three, show a "rotten" stem on one of my Maris pipers, and also a discoloured patch on one of the Maris piper leaves(different plant) Couldn't this be late potato blight.

What should I do - cut back the affected foliage and spray with Bordeaux mixture?

If so, how aggressively should I cut?

Any advice would be much appreciated.

Thanks

Plot88

[SueSteve]

They are great pics, thats what I had on 2 of my Ambo, now dug up.
I dont have the brown stems though, just the yellow and brown patches.
At the lottie, neighbours have the same on their plants, but fortunately not mine (last visit saturday!).
Would love someone in the know to confirm if this is or isnt blight.
Thanks,
Sue

[Trevor_D]

Don't think it is, but I'd spray anyway.

My Charlotte are dying back. (I thought it was blight & sprayed - even dug one up to check. It was fine.) The weather has been so odd this year, they've just finished growing.

[manicscousers]

I thought potato blight made the plant a smelly, wet black mess..some of ours were like your picture, the rest of the plant looks ok, just a bit of damage due to the weather..hope someone answers your question soon  :)

[Tee Gee]

I don't think it is on your Charlottes but not so sure with your Maris Piper.

Did a google and found these pictures (click on them to enlarge) and have a look for yourself.

http://tinyurl.com/ywqlsu

[ladybizzy]

I can't help, but your Charlottes are exactly like my Duke of Yorks - they have got worse over the last week, so I have cut the haulms off tonight, as I can see signs of it on other varieties

[e4e5Kt-f3]

Agree with Tee Gee, Maris looks to be early Blight. I would dig out that root as the blight is in the stalk. Cut away the nearby haulms surrounding that plant. Dispose of in a plastic bag to the tip or burn. Spraying is a preventative not a cure so you need a dry day (sic) and spray BEFORE any signs appear.  (hence the smith period advice)
Copper based sprays should cover 80% of the leaf area including the underside!
Best spray is Fubol but not easy to get hold of, needs less coverage to be effective.
If the spread of the spores is persistant make a bold decision to cut down alll the haulms and leave the potatoes in the ground for the skins to `set`.
You may need to spray once a week if this humd weather continues.
ps. I`ve cut down all my picasso and pink fir stalks and resigned to a small crop this year.

[hippydave]

your pots look a lot like mine, Ive been away for just under a week went to the lottie tonight and the pots are looking a lot worse for ware but i was really upset when i went into the greenhouse and found all my toms had started to rot and were very smelly so now I'm resigned to to the fact that Ive got blight, just got to remove the toms and bin them and hope for the best for the pots.

does anyone know if i can plant peppers and cues from my home greenhouse in the lottie greenhouse without any ill effects from the blight i was thinking of spraying with jayes fluid would this kill any spores that may be left...

[Kepouros]

Although it`s always difficult to be precise from a small photo, I would stick my neck out and say that the Charlottes are simply  dying back because they have done all that they want to do.  The spotting is probably due to minor mineral deficiences caused by the continual rain recently.  There certainly doesn`t appear to be any evidence of the typical `halo` usually associated with blight. I would be inclined to get them up anyway before the slugs get them.

The Maris Piper appears almost certainly to have blight, and I would be inclined to cut down the whole plant very carefully to ground level so as not to distribute free spores on to the surrounding plants (although they probably have it by now anyway). Don`t dig the plant up yet - it takes about 14 days for the skins to set, and for any spores on the soil surface to die, and premature disturbance of the surface may bring the spores into contact with the tubers.

Spray the remainder. As e4e5Kt-f3 says, this is not a cure, but it should help to slow the spread of the infection, then keep picking off any newly affected leaves that show, and cut down all plants that become badly affected.

Contrary to popular belief, blight does not usually turn the whole plant into a rotting black mess overnight, and unless the blight attacks the lower stems, the plants can, with careful management, often be kept growing for another two or three weeks before it becomes necessary to remove all the tops to save the crop.