We have a relatively recently planted crop of potatoes, maybe 6 to 8 weeks old, without using any kind of pesticides - and they had been doing fine with watering almost every day, or every other day.

Then in the space of 24 hours, all the potato plants seemed shriveled up, or kind of withered, as in the photos attached. But, as seen in photos, some other plants/ small weeds nearby survived intact.

Some of the photos are around 48 hours after they had looked absolutely fine, and healthy. Any idea why this happened. Could it be due to some kind of parasite?

Thanks.