The Biochemical Basis of Inorganic Insecticides: A Review

Because of a growing world population, there is pressure to increase and preserve the food supply by using insecticides and other agricultural chemicals. The concept of insecticides is not new and man has been using insecticides for thousands of years to try to control these pests. An insecticide is defined under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) as any substance or mixture of substances intended for preventing, destroying, repelling or mitigating the effect of any insect including crawling and flying insects. By chemical nature, one traditional classification of insecticides places them in one of two groups: Organic and inorganic insecticides. Insecticides have also been classified based on their mode of entry and they are those that act as stomach poisons, contact poisons and fumigants. Insecticides have also been classified under the Insecticide Resistance Action Committee (IRAC) based on their mode of action and they are those that affect; the nervous system, the production of energy, the production of cuticle, the endocrine system and water balance. The mode of action of some of these inorganic insecticides are yet to be fully understood but some have been shown to affect the nervous system, energy production and water balance. Inorganic insecticides such as arsenates affect energy production in insects by replacing inorganic phosphate in the sixth step of the glycolytic pathway thereby uncoupling the ATP formation. Fluorides also affect energy production by forming a complex with phosphate and magnesium which competitively inhibits the enolase enzyme thereby uncoupling the ATP formation. Barium affects the nervous system by blocking the potassium ion gated channels which can lead to vasoconstriction, paralysis and death eventually. Mercury and phosphine also affect the nervous system by inhibiting acetylcholinesterase resulting to hyperactivity and death eventually. Boric acid, silica aerogels and diatomaceous earth affect water balance in insects by absorbing lipids from the outer layer of the insect’s exoskeletons causing it to dehydrate.

The Biochemical Basis of Inorganic Insecticides: A Review

Okeke, Chioma Blessing,The Biochemical Basis of Inorganic Insecticides: A Review