The phenomenon of using a predator for controlling a pest is known as:

Which free-living fungus is used in biological control of plant diseases?

Given below are two statements.
Statement $I$: Baculoviruses are pathogens that attack nematodes.
Statement $II$: Baculoviruses are used as biological control agents in ecologically sensitive areas as they are species-specific in their action.
In the light of the above statements, choose the correct answer from the options given below.

The largest group of insecticides produced by plants is .......

Protozoan like $Nosema$ $locustae$ is used for controlling the target pests like . . . . . . .

From which of the following is a natural insecticide obtained?