Pesticides are intensively used to protect cereals from pests, but they are known to increase pest resistance and affect the environment and non-target organisms, including humans, which points to the need for sustainable alternatives. Some of the main cereal pests are the weevil Sitophilus spp., which proliferate on a cereal-exclusive diet thanks to a mutualistic association with the intracellular symbiotic bacterium (endosymbiont), which provides the insect the nutrients that are scarce in the grains.