At what stage of the mosquito life cycle can larvicides be effectively applied?

Larvicides are specifically designed to target the larval stage of the mosquito life cycle. This stage is crucial for effective intervention because it is when mosquitoes are still in the water and are growing and developing. By applying larvicides during this stage, they can disrupt the growth and development of the larvae, thereby preventing them from maturing into adult mosquitoes that can emerge and breed further.

If larvicides were applied to the adult stage, it would be too late to prevent the growth of new mosquitoes, as they would have already developed and potentially laid numerous eggs. The egg stage is also not suitable for larvicides since the product needs to act on living larvae to be effective. Similarly, applying larvicides at the pupal stage would not work, as pupae do not feed and are in a transitional phase. Thus, the larval stage is the optimal time for larvicides to effectively reduce the mosquito population.