Pesticides and Pest Control

A method to eradicate pests using the pest's natural predators or parasites, which is environmental friendly is termed as biological method.

Killing of insects using insecticides does not involve plasmolysis. The action is done by chemical means.

Photosynthetic inhibitors at photosystem II site A type herbicides are chemicals that disrupt photosynthesis, so carbohydrates cannot be produced and the plant dies. These chemicals have activity when applied to leaf tissue, but they are typically used as pre-emergent applications as they are taken up by the roots of newly emerging weeds. For example, Atrazine, Hexazinone, Terbacil, Simazine.

Glyphosate targets EPSP synthase (5-enolpyruvyl shikimate-3-phosphate synthase) in the shikimate pathway. Bromoxynil is detoxified by nitrilase enzymes. Sulfonylureas inhibit acetolactate synthase (ALS), a key enzyme in branched-chain amino acid synthesis. Dalapon is metabolized by dehalogenase enzymes. Option A correctly matches each herbicide to its target enzyme.

Bacillus thuringiensis is a gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide.

Correct answer. Agrobacterium radiobacter is an effective, commercially applied, biological control agent for the prevention of crown gall disease caused by many virulent strains of Agrobacterium tumefaciens and A. rhizogenes. Trichoderma harzianum is an effective biocontrol agent against several fungal soil-borne plant pathogens.

This option is correct because Bacillus thuringiensis (or Bt) is a gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide

Bordeaux mixture is a classic copper-based fungicide composed of copper sulfate and lime. It has been widely used in agriculture since the late 19th century to control fungal diseases on various crops. Carboxin is a systemic fungicide, chloropicrin is a soil fumigant, and mercuric chloride is a mercury-based compound (now largely banned).

None of these is a commonly used pesticide.

Excessive use of pesticides pollutes the lithosphere. Lithosphere is the solid crust from the centre of the earth to the outer surface. It gets polluted due to the dumping of pesticides and herbicides. 

Pesticides are chemical substances specifically designed to control or eliminate pests that damage crops, spread disease, or cause nuisance. They include insecticides, herbicides, fungicides, and other agents targeting various pest types. The other options are too narrow - pesticides work against many types of pests, not just insects, plantlets, or weeds.

DDT is an insecticide (“insect” + “cidal” – killing). It is used to kill a variety of insects and pests, particularly mosquitoes. It should be noted here that though DDT is useful but at the same time, it is a pollutant and hence, its use must be limited. Apart from DDT, all other options given here are vaccines and hence, they cannot be used to kill mosquitoes because their function is to give immunity inside our body. BCG is a vaccine against TB; ATS is Anti Tetanus Serum and DPT is a triple vaccine against diphtheria, pertusis and typhoid.

Enzymes released by bacteria helps in breaking down biodegradable waste products.

No, environmental factors are not included in PEST.

DCMU  3-(4-chlorophenyl-1,1-dimethylurea} inhibits PS2 phase of phtosynthesis.