Doubling time is the time a population growing at its intrinsic rate of increase takes to double: 0.693 divided by r_m. An r_m of 0.2 per day gives 3.5 days; 0.35 per day gives 2 days. It is the most intuitive way to explain why a week of inaction matters.
In practice
Doubling time is an upper bound from lab conditions; real rooms with predators or poor food run slower. Even so, a pest that doubles every 3 days goes up about 128-fold in 3 weeks (seven doublings), which is why weekly scouting is the minimum.
Don't confuse with
- Generation time: birth to next birth, several doublings long.
The average time from a female's birth to the birth of her offspring; at a set temperature it fixes how often a pest population multiplies.The per-day rate at which an unchecked pest population multiplies under set conditions, from a life table; N(t) = N0 x e^(r_m x t).
