A method and projectile to combat nests of harmful insects comprising: - the provision of a mould with cavities shaped like a projectile； - the pouring into the mould cavities of a liquid pesticide suitable for the type of insects to be combated； - the freezing of the liquid pesticide poured into the mould cavities； - the removal of the pesticide frozen projectiles from the mould cavities； - the firing of the pesticide frozen projectiles into the inside of the nest and - the distribution of the liquid pesticide inside the nest during the gradual thawing of the projectiles at room temperature.
