Potato Blight

nick615

For those who didn't see the re-run of Rick Stein's programme about Cornwall on TV last night, he talked to an old gardener called John Harris who had a large crop of spuds and no blight in his large walled garden.  His regular method of prevention is evidently full cream milk, diluted with water @ 10:1 - 10 parts water to one of milk.  Never fails - he says.

Dovefromabove

I suspect the protection provided by the high walls surrounding the veg garden may also have something to do with it. 

I suspect that if something as easily available to them and as cheap, simple and safe to apply as milk were really effective,  my brother and all the other big potato farmers would be spraying it all over their crops. 

😉 

robairdmacraignil

Saw the same piece of TV and it sounded interesting and it reminded me of material I read before that advocated in a similar way using aerated compost tea as a spray on the potato leaves to reduce the damage from blight. This article is an example of some study in the area. I think the material I read before found it effective if the compost tea application was fairly regular and it makes sense to me that something like compost tea or diluted milk could increase the level of microbes on the leaf surface that might compete with blight spores and make it more difficult for them to get established. Big potato farmers as far as I know use commercial fungicides when conditions suit blight transmission. The price of these for large scale users might be at a level that experimenting with alternatives may seem unnecessary.

Happy gardening!

Dovefromabove

The premium paid for veg grown without fungicides is sufficient I’m pretty sure farmers would use milk if it worked well enough to be worthwhile 😊 

robairdmacraignil

Dovefromabove said:

The premium paid for veg grown without fungicides is sufficient I’m pretty sure farmers would use milk if it worked well enough to be worthwhile 😊 

I think there are lots of veg that can be grown well without fungicides but was posting specifically about potato which is almost always effected by the blight fungus. Even organic growers use Bordeux mixture as a chemical means of stopping blight on potato crops. I'm just saying I can see how the diluted milk method might work and provided a link to a related article where a study found compost tea had an effect on reducing blight on potatoes. I'm not going to pretend to know enough about commercial vegetable growing to know what farmers are likely to do but think organic vegetables only account for a limited portion of the overall market so a lot of farmers don't see that avenue as being an option for them and even more so for the potato crop which is so frequently attacked by blight. The idea of diluting milk to spray on multiple acres of crops is a very different proposition to doing so for a home scale vegetable plot and I just don't think the cost saving would be that significant for larger farmers but you obviously know better.

Happy gardening.

fidgetbones

I grow Sarpo potatoes. Blight free, even when grown next to other sorts that succumb.  Even at my sister in laws in Wet Snowdonia.

Hostafan1

Unless they only sprayed half the crop one year and made a comparison, it's not really " evidence" any more than saying something like " my grandad smoked 40 a day and lived to be 90" doesn't mean it was the fags which kept him alive longer

ZeroZero1

Hostafan1, “proof” smoking prolongs life ? Lol