I tell my personal sad experience on the disappearance of seedlings.We raised it at home, then transplanted into a greenhouse.On the night sheltered, afternoon reopened.And it has always been fine.
But then came the heat once - at once.In the morning all went to work, it was very fresh.Greenhouse touch did not, remained closed.The sun literally hell.When in the evening we saw that our seedlings, believe me, even Stalks he did not find it!It's so seedlings burned roasting under the film !Imagine the heat from the greenhouse was because there the manure was laid, the sun was shining so plus the greenhouse effect!That's the result - even a trace is left of the fragile plants.
If you have such a situation, it "ate" your seedlings heatwave.
Of course, I do not know the conditions of your seedling cultivation.Eat roots could and cricket - but then the plant would not have disappeared, and lay on the bed limp.
I could eat a goat, for example.Then you would see the marks of its hoofs.
So, speaking of the "disappearance" of seedlings, I bow to his first option.
18 December 2016