With all grubs and all animals that break out from the grub
state, generation is due primarily to the heat of the sun or to wind.

Ascarids are more likely to be found, and grow with unusual
rapidity, in places where there is a deposit of a mixed and
heterogeneous kind, as in kitchens and in ploughed fields, for the
contents of such places are disposed to rapid putrefaction. In autumn,
also, owing to the drying up of moisture, they grow in unusual
numbers.