[strider84]

Hi all,

Have a problem with one of my potato plants think it may be black leg?

IF it is black leg do I just chop the plant off and hope for the best for the tubers or will it be to late?

Also will it spread onto my other potatoes?

Many thanks

[mumofstig]

yes, blackleg - there's a lot of it about this year 
Take off tops and lift potatoes, which are usually ok to eat if you catch them before the rot sinks down into them.

This helps stop the rot spreading, but I have to say most of my Charlottes got BL despite me lifting them as soon as they showed any sign of it 

[strider84]

Thanks for your help I was a bit worried about lifting them as they have only been in 2 months (moved into new place in June and thought I'd give them a try despite being very late).

Lifted the one plant effected and all ok

For the foliage that has come out ok to compost? Or does it get added to the burn pile?

Thanks again

[mumofstig]

I burned mine!

[Grubbypaws]

I have blackleg in one of my containers of pink fir apple. I have lifted the potatoes and although they are on the small side it is a good crop. I will have to see if the flavour is as good as last year though as I am sure that I read somewhere that the flavour gets better the longer you leave them.

I have four more containers of pink fir apple which at present are not diseased but they are in close proximity. Am I OK to wait and watch or should I lift them as well?

[mumofstig]

It is supposed to spread from one plant to another, through the soil, so the other pots should be ok - but - if you used bought compost in the pots, it seems it was on the seed potatoes you planted 

[Grubbypaws]

The compost is our own home grown so I will wait and watch. Does blackleg just attack potatoes? Am I OK to re-use the compost that the affected potatoes were growing in?

[mumofstig]

Just the potato family, everything else should be ok 

[JayG]

Found this:

The blackleg bacterium survives poorly in soil. Although other members of the pectolyic erwinia survive in surface water and in the soil environment, all evidence suggests that the blackleg bacterium does not survive very well outside of association with host plant tissue. Hence, the seed tuber is the most important source of inoculum in the blackleg disease cycle.

The above is an extract from a very hefty article here:
http://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/Blacklegpotato.aspx

As Mum says, unless your compost actually had blackleg infected tubers already in it, the disease must have come from your seed potatoes - hopefully it was only the odd one (it usually is when grown in open soil although this year it has been a bigger problem for many than usual.)

It's obviously very important to make sure as far as possible that there are no "volunteers" left to possibly re-infect next year's crop, although outdoors rotation of the crop should take care of that.