Pesticides and Pest Control

Caprylic acid is used commercially in the production of esters.

Manual method refers to hand picking of the weeds. Chemical method refers to spray of weedicides to prevent the growth of weeds. Biological control method refers to the use of some insects or other organisms, which help in the destruction of weeds by feeding on them and thus is the correct option. 

Leaves of a neem plant are used to mix with grains to keep insects away, because of their insecticidal property.

2,4-D is a weedicide that can kill unwanted plants (weeds) growing in the field.

Nuclear Polyhedrosis Virus (NPV) is a well-known biological pesticide used to control various insect pests in crops.

Work Culture is the factor of 'S' in PEST analysis and 'S' stands for social and cultural environment.

Fiscal Policy is the factor of political and legal environment in PEST analysis.

Monetary Policy is the factor of political and legal Environment in PEST analysis.

Weedicides are specific chemicals used to kill or inhibit the growth of unwanted plants (weeds) in a field without harming the main crop.

Pesticides are chemical substances used to control, repel, or kill pests, including insects that damage crops.

Threshing is the process of separating grain from the harvested crop stalks. Option B correctly identifies this process, though it contains a typo. The other options describe different agricultural operations like spraying pesticides or adding manure to fields.

Biological magnification (or biomagnification) is the process where the concentration of toxic substances, like DDT, increases at each successive trophic level in a food chain.

Pesticide is used to prevent damage to crop, antiseptic is used to prevent infection of wounds.

Pyrethrum, Nicotine, and Cinerine are all naturally occurring alkaloids found in plants that possess insecticidal properties.

DDT (dichlorodiphenyltrichloroethane) is a synthetic organochlorine compound that was historically used as a potent insecticide.