Spuds with blight

Hi chums. Last week I dug up my main crop spuds (Desiree) and found that a few of them had blight. Question is, should I refrain from growing spuds there again at any time in the future ? If so, how long ?
Cheers...freddy.

 

Did you notice any infection on the leaves? (If not are you sure it is blight on the tubers?)

For blight I reckon wait 3 years minimum. Make sure you have got every last tiny tuber out of the soil so no "volunteers" grow back next year. Remove any that do grow back as soon as you see them.

If you had any volunteers growing anywhere else in the garden / compost heap this year then treat them the same, and don't grow spuds there either :(

Ditto for anything else that might have been a carrier, I suppose. Tomatoes for example.

I wonder if there is a means of sterilising the soil?

 

Hi Kristen. No, I didn't notice blight on the leaves, BUT, the said spuds were grown on another plot I have up the road, and I hadn't been up there for a while, so I wasn't able to see them at the crucial time. The tubers were discoloured and matched the description in the 'bible' (that'll be The Herb And Vegetable Expert )
That's something of a blow, as the said plot was mainly for bulk crops, like spuds and onions. Thing is, my onions have problems too, white rot ! Hmm, I might have to give up that plot :(
Cheers...freddy.

 

..

Blight is mainly an airborne disease spread by spores when the conditions are ripe.
That is high humidity with high temperatures over a certain period, then we get blight, this is usually mid July onwards.

The only practical way we gardeners have of trying to minimise the problem is to pull "ALL" the leaves and staulks off all plants as soon as brown/black patches of blight are seen on one!

Commercial growers resort to copper fungicide as a preventive spray, otherwise they would never have any crop.
It is not really practical for amatuers to use as we cannot get enough pressure or fine enough spray to be effective, (no doubt someone will say they are able to spray successfully) but I have never succeeded so have giving up trying!

Normally one should try not to plant potatoes in the same spot for about three or four years according to the experts, blight or no blight.

In 2007 I had almost all my main crop ruined by blight, and I failed to get the leaves/stalks off in time when it was first noticed.
In 2008 there was none on my crop as conditions were not right for it, not so this year but I got all the stalks off the plants as soon as first sighted.

I also dug out all my crop as quickly as I could to stop them rotting in the ground.
I have checked those in storage and have found some before they have gone putrid!

Hope next season is better!

 

I read somewhere once that spraying the foliage with water that nettles had been soaked in was supposed to work as fungicide against blight (although the author admitted it wasn't very potent). They claimed that some chemical in the nettles makes for an inhospitable environment for fungal spores. I've never tried it though, and have no idea if there is any scientific backing for the authors claims.

I wouldn't grow spuds in the same spot for two or three years, just as a precaution.

On the point about commercial growers using copper based fungicide, I think the main difference there is that with modern farming methods, they have to be far more careful about blight. They often have little choice but to use the same patch of ground over and over for their crops, and as they often get contracts demanding that they produce a certain quantity of a specific crop, there is little room for maneuver, so they have to use potent fungicides routinely.

 

Well we have had blight on our main crop for a long time (surrounded for a long time by fields full of potatoes). So we stopped growing main crops and now only grow First Earlies (Lady Crystl) and Seconds(Nadine). Both of these are out long before the weather conditions are right for Blight. They both store well until the new season the following year. No trouble, no blight.

 

"I also dug out all my crop as quickly as I could to stop them rotting in the ground."

I've read that after removing the foliage the crop should be left in the ground for a while (how long?) so that spores on the surface are not transferred to the tubers.

Although I expect that the disease will be in the process of transferring from the foliage to the tubers, so timing is probably still of the essence.

 

That's a useful tip. I might start doing that. I've never had a case of blight yet (fortunately), but that's no reason to ignore the risk.

 

Hi guys, thanks for the replies :thumb: All things considered, it looks like I'll have to give up the plot. Thankfully, in my own garden, pests and diseases aren't TOO bad and this is where the most of my veggies are grown.
Cheers...freddy.

 

Not planting potatoes in the soil for several years does not help in the prevention of blight, neither is there any need for soil sterilisation. The blight needs living tissue to survive from year to year. this means that you can compost potato leaves and it will not pass on the disease, the same with tomato haulm as they are dead tissue. The blight can survive on tubers and blight often starts off from volunteers from the previous blight year. So you really need to get every tiny little tuber out and any that regrow next year destroy them as soon as you spot them.
I have had blight on my allotment and I would not let a thing like that defeat you. I am going to concentrate on blight resistant varieties and spray with Copper fungicide before the disease takes hold. If that fails then I will do what Palustris does.