Question

Define pest. Is the term "scientific"? Then, discuss what biocides are, in which ways biocides are classified, and why they often don't work. (Subject: Environmental Biology)

Answer 1

Pest are destructive insects or any other animals that infects plants, crops, lifestock etc. It includes animals that carry harmful microorganisms. Mosquitoes, insects, flees, cockroaches are some insect pests. Pest is just a general term for a group of insect. Hence, it is not a scientific term.

Biocides are chemicals used to eliminate living organism via chemical and biological means.

Biocides can be broad spectrum or narrow spectrum. Broad spectrum biocides act on different sites such as the cell wall, cell membrane etc. Narrow spectrum biocides work on lesser pathogens. Biocides are classified into 22 types of products that belong to four groups. The four groups are disinfectants, preservatives, pest control, and other biocide products.

A) Disinfectants: There are five groups PT1-5.

PT1= Products for human hygiene for disinfection of skin and scalp

PT2=Disinfectants and algaecides that are not applied to humans or animals. They are used to disinfect swimming pools, surfaces, furniture etc.

PT3= Disinfectants used for vetinarian hygiene which have antimicrobial action

PT4= Disinfectants used for cleaning food utensils, food equipments, storage containers etc.

PT5=Disinfectants used for drinking water for human and animal use.

B) Preservatives: There are eight types P6-P13

P6= They are used for the preservation of manufactured products such as rodenticides, pesticides etc

P7=They are used to preserve films and coatings

P8= They are used for preserving wood and wood products from insect pests.

P9= These are Fibre, leather, rubber and polymerised materials preservatives

P10= These preservatives are used for construction materials

P11=They are preservatives for liquid cooling and processing systems

P12= They preserve for slime control on materials and equipment

P13= They control microbial deterioration in fluids used in working or cutting metal, glass or other materials

C) Pesticides: These biocides are involved in controlling pests. They are of seven types; P14-P20.

P14=Rodenticides, P15=Avicides for bird pests, P16=Molluscides, Vermicides and control of invertebrate pests, P17=Piscicides for fish pests, P18=Insecticides. P19=Repellants and attractants of insects, P20=Control of vertebrate pests

D) Other Biocides: They include antifouling products (P21) and embalming products (P22)

Biocides are always not effective. Disinfectants will only prevent the growth of microorganism. They will not kill the pathogen. They are also not effective against bacterial or fungal spores or microbes that have gained resistance to the agent. Preservatives also will prevent the pest from attacking a equipment or product. Some biocides have a narrow range of activity. Hence, they will not prevent all pathogens growth. It may not be possible to completely prevent mould growth on equipment as most biocides cannot penetrate deep inside the material.