Q.54 Which of the following is/are prophylactic (preventive) methods of plant disease
control
(A). Eradication of alternate host
(B). Spraying plants with pesticides and fungicides on a regular basis
(C). Crop rotation practices to control soil borne diseases
(D). Growing antagonistic plants
Choose the correct answer from the options given below:

1. (A) and (D) only.
2. (A) and (C) only.
3. (A), (B), (C) and (D).
4. (B) and (D) only.

Prophylactic Methods of Plant Disease Control

Prophylactic methods prevent plant diseases before infection occurs. This article explains the correct answer for Q.54 with detailed breakdowns of all options.

Correct Answer

The right choice is 3. (A), (B), (C) and (D). All listed methods qualify as prophylactic since they aim to avoid disease establishment by reducing pathogen inoculum, host susceptibility, or environmental favorability.

Option (A): Eradication of Alternate Host

Eradicating alternate hosts removes pathogen reservoirs that could spread to crops. This preventive tactic breaks disease cycles before primary infection.

Option (B): Spraying with Pesticides and Fungicides

Routine spraying creates a protective barrier on plants, stopping pathogens from colonizing surfaces. Though often called curative, regular application is prophylactic by preempting outbreaks.

Option (C): Crop Rotation Practices

Rotating crops disrupts soilborne pathogen buildup by denying continuous hosts. This cultural method prevents disease escalation over seasons.

Option (D): Growing Antagonistic Plants

Antagonistic plants release compounds or harbor microbes that suppress pathogens. Intercropping them prophylactically inhibits disease via biological competition.