Face to face with The Blight

Wednesday 1st August 2012
Summer could be over!

I didn't mention this before, but when I was wrestling with the (non) self-drilling screws on the polytunnel I wrenched a shoulder muscle fairly badly and have been trying to rest it ever since. This was not helped when the geese discovered they could easily hop the fence. I had to catch them and clip their wings, an adventure which set back the already slow recovery of my shoulder. Next morning, one of them was back over! So I had to attend to the fence.

The point of this shoulder story is that, lurking in the background has been the urgent need to venture into the maincrop potatoes. I need to pull the tops, hopefully before the tubers become infected, but the fat hen and sow thistles have grown gigantic and will need to come out too. Last time I tackled a giant sow thistle it beat me!

Everything I've read about blight is starting to make sense now I've come face to face with it. I'll be much the wiser next year. For starters, I now know what it looks like. More importantly, I know how it behaves.

It starts as blotches on the leaves, which quickly shrivel up and die. Then it heads down the stem, which turns brown and basically rots. Now it's reached the tubers. Bad news.
Some of my spuds have, unfortunately, reached this stage. The potatoes nearest the surface are infected, showing spots of white, furry fungus, or just rotting down to a mushy mess. I don't know whether I'll be able to save any of those further down.

Others still have the stem fairly green and intact, like those below. With these, I've pulled the stems and left the tubers undisturbed in the ground. They need to stay there for two weeks so they don't pick up the blight from the soil surface when they come up.
Of course, there's also the question whether or not they've had enough time for the tubers to grow properly anyway.

Blighted spuds.
Not the worst though.

One variety, Sarpo Mira, seem unaffected at the moment. It is supposed to be the most blight resistant available. I've left these plants, but I'll be keeping a very close eye on them. If they cook nicely and taste good, I suspect they'll be high on the list for next year. It'll be interesting to note how the tubers have faired on the other varieties too.

Although not a great situation, I was always going to meet blight at some point, so I will just have to treat this year as a learning experience and salvage what I can.

One thing I do know is not to put the diseased material on the compost! It needs burning straight away.

 



Tops cleared away and burning.
In the background are the Sarpo Mira, which still seem healthy.
(Not the really tall ones. They are Jerusalem Artichokes!)