Allotment Gardening Advice Help Chat

Growing => Grow Your Own => Topic started by: surbie100 on July 05, 2012, 17:11

Title: Brown bits on potato leaves
Post by: surbie100 on July 05, 2012, 17:11

Can any of you tell me whether this is the dreaded b-word?

The brown spots/lesions don't seem to have concentric circles inside, and are on leaves on my balcony potatoes (one of which had blackleg before). Similar marks on yellowing leaves on my tomatoes, which have been on the plot for 2 weeks and were perfect before being planted out there (they'd previously spent about a month on the balcony).

Not having grown anything before, I'm not sure what I am looking at.

Thanks!
Surbie

Title: Re: Brown bits on potato leaves
Post by: Kleftiwallah on July 05, 2012, 17:25

The weather conditions are ideal for (that word) to spread.  Untill proved otherwise I should say you have it.   If it's any consolation we have just cut down all the floiage from our early, 2nd early and maincrop spuds before the spores travel down and spoil the tubers.

Cheers,    Tony.

Title: Re: Brown bits on potato leaves
Post by: arugula on July 05, 2012, 17:26

Have a look at this thread Avoiding and recognising blight (http://chat.allotment-garden.org/index.php?topic=56717.msg668473#msg668473). There are some clear pictures and links to others.

Title: Re: Brown bits on potato leaves
Post by: surbie100 on July 05, 2012, 21:57

Will take the affected leaves off and start spraying the others. My area had a full Smith Period over the last 2 days, so this might be it!

Agyllie, just so you know the links on the other thread are broken. But as you say, there are plenty of Google images.

Thank you both for the advice.

Surbie

Title: Re: Brown bits on potato leaves
Post by: mumofstig on July 05, 2012, 22:29

I've deleted the broken links - thanks for letting us know.

Title: Re: Brown bits on potato leaves
Post by: Salmo on July 05, 2012, 23:31

I will stick my neck out and say I do not think that is blight. It could be magnesium defficiency. Magnesium defficiency tends to be between the veins and will only increase slowly. Blight lesions will develop rapidly and at random especially in warm and humid conditions. Turn the leaf over and you should see mould.

Title: Re: Brown bits on potato leaves
Post by: surbie100 on July 06, 2012, 10:47

Hi Salmo,

Thanks for sticking neck out - but there isn't any mould. Looking today there were a few more leaves with more characteristic blight bits (according to comparisons with Google images anyway!).

Have removed leaves, sprayed with Bordeaux mix, crossed fingers...

My plot neighbour was asking what the brown spots on his potatoes were, so I think it's just a matter of time before it gets to my ones on the plot! (despite the spraying)

Surbie

Title: Re: Brown bits on potato leaves
Post by: Goosegirl on July 06, 2012, 14:18

It's not something sucking the sap out of the leaves so you are left with a brown "skeleton"? Try spraying with insecticidal soap or whatever, as blight is usually very quick in its decimation.