As these resistant few breed the gene for pesticide resistance increases and thus in each subsequent generation a greater majority of individuals are resistant. The phenomena of resistance development can occur only if the population is targeted, as are cockroaches, as a pest. Since beneficial insects are not normally considered pestiferous, they are not the target of insecticide application and do not normally develop resistance. Preservation and perpetuation of the complex of cockroach natural enemies depends heavily on the non-use of pesticides. Silica gel is simply finely ground sand or glass that rubs the protective waxes off the cockroach cuticle resulting in cockroach dehydration.
Cockroaches walking across an area dusted with boric acid pick up the dust on the sticky cuticle.
As the cockroaches groom off the boric acid dust they ingest it into their stomach and it kills them. Ultrasonic Devices Extensive research has shown that ultrasonic devices neither kill nor repel cockroaches. In conclusion, reduction of a cockroach infestation without using insecticides can occur only if the insect is first prevented, or excluded, from establishing a population. Once a population is established the elimination of food, water and harborage resources must be performed. This, in many cases, involves a change in lifestyle by the homeowner.