Eighty five per cent of the immature stages are eggs and larvae. The solution to flea control is to concentrate on the eggs and larval stages before they develop the cocoon or pupae. The eggs and larvae need the correct amount of humidity, sunlight, and food source to survive. These facts help us to decide where these flea stages may hide. For instance, outside flea eggs and larvae can be found in the shaded, cooler areas.
Examples are under tree limbs, bushes, dog pens, under decks ,etc.
These immature stages generally cannot complete their development out in the sunny areas of your yard, so there is not point in using flea products in the middle of the sunny yard. In the house, flea larvae and pupae will be deep in your carpet or just under the edge of furniture, not more than a few inches out of the light. Concentrating on flea control in carpeted areas is the most productive for indoor control. If you see or feel fleas on you, they are usually the pre-emerging fleas which are the ones coming out of the pupae. Immature fleas can stay in the pupae stage for months until all the right conditions enable them to break out of their cocoon.