BioChemical pathways
& Their Application in Biotechnology
What are Insecticides?
Insecticides are defined as fatalistic agents with either a chemical or biological origin that is specifically designed to control unwanted insects. The primary mode of action of insecticides is to poison and damage the nervous system of the insects it comes into contact with. Often times, if a lethall enough dose is applied, the neural pathways become damaged as well causing motor problems, tremors, and respiratory problems. [1] [2] [3] [4] [5]
Nervous System: Insect Edition
Before we can hop right in and begin learning about how different insecticides inflict terror on different pathways within an insect, it is crucial to first develop a clear understanding of how the central nervous system of a typical insect works.
How Do Insecticides Work?
Let's begin! Insecticides typically work through three major methods.
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Systemic vs. Contact
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Type of Compound
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Mechanism of Action
Systemic vs. Contact
Systemic Insecticides refer to a type of chemically created pesticide that is soluble enough in water to be absorbed into the cell structure of the plant, and move around in its tissues. It is important to note that these types of insecticides are actually within the plant structure, rather than located on the external surface. The movement of these insecticides occurs within the plant’s vascular system through the phloem and xylem. This fatal circulation of chemicals within the plant’s tissues will effectively kill the insects that feed on them. [4] [5] [6]
Type of Compound
Contact insecticides refer to a type of chemically created pesticide that come into direct contact with the insect. These insecticides infect the insects by entering through their skin or respiratory system. Unlike systemic insecticides, they are not soluble enough in water to be absorbed into the cell structure of a plant. Thus, when a contact insecticide is applied to a plant, it acts as a form of residue. And when the insect lands on the plant, the residue is absorbed by their feet which then enters the blood stream and damages the nervous system. [6] [7]
By classifying insecticides by compound, there are three categories: inorganic, organic, and naturally-occuring. [6]
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Inorganic insecticides come across as the oldest type of pesticide. These compounds consisted of metals referred to as "heavy" - these included arsenic, copper, fluorine, and sulfur.
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​Organic compounds are the most reknowned ones, having been manufactured during the 40s. These compounds are created with Carbon molecules.
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​And the last type, are the naturally-occuring insecticides. These, hence their name, are all natural - made from various flowers such as nicotine and pyrethrum.