I thought the potatoes I dug were fine, even though the plants were heavily hit with late blight. But after three weeks of storage, I have realized they’re not fine. The fingerlings and Russets that were hardest hit and that I cut down and dug first are turning brown and rotting in their bags.
[Late blight produces] characteristic coppery-brown discoloration of the potato flesh under the skin…. Infection of potato tubers arises from spores that develop on foliage. Tubers exposed by soil cracking or erosion of hills may come in contact with spores washed down from infected leaves and stems by rainfall or irrigation. Tubers infected during the growing season may partially decay before harvest. Tuber infection may also occur at harvest when tubers contact living spores remaining on infected vines. Little if any tuber-to-tuber spread of late blight occurs during storage if tubers are kept under cool, well-ventilated conditions. Ohio State Univ Extension Fact Sheet on Late Blight
And here’s a very helpful comment Soilman left me a few days ago:
Blight is a pain, isn’t it?
I’ve given up with tomatoes. I just can’t bear seeing them struck down with blight every year. Potato blight, though, can be managed. I get it every year (it’s a routine hazard in the UK climate), but I’ve never had a crop failure. The key is to remove all the haulms when the blight starts to really get hold.
You then wait at least 10 days before you dig the potatoes; without the haulm, the blight spores get fried in the sun. Choose a warm, dry day to harvest the potatoes. If they’re thoroughly dried before storage, you should be OK. It’s always worked for me. One crucial point: NEVER put potato haulms on the compost heap. Burn them.
And here’s a what the CSA farmer at Piccadilly Farm in southern New Hampshire wrote about late blight yesterday:
A note on the Late Blight front: farmers in all parts of New England are reporting serious losses in potatoes and tomatoes. The spread seems to be snowballing, and any prolonged cool, wet weather exacerbates the problem. We scout daily and have seen no sign of Late Blight here. The tomatoes look great and are beginning to size up. Every passing week means more spuds sizing up and less loss on that crop if we do get the blight here. I know I’ll be counting down the weeks until the relief of that last potato harvest in October (12 weeks…)! Coupling this stress for vegetable growers with the devastating financial crisis that dairy producers are facing, many regional farmers are having a tough go of it.
These rotting potatoes were dug right after I cut down the foliage, so I guess that was the error. I have lots of potatoes still in the ground now though I have cut down all of the foliage. Guess I’ll just be patient for a few weeks before harvesting more.
And, someday I need to figure out how to dispose of my compost pile. Its full of blighted tomato and potato foliage. I don’t think anything around here is dry enough to burn. Maybe a big deep hole? I don’t know … Can I just dump it in the woods?