Plant Protection (Entomology and Plant Pathology)
What the exam tests
Plant Protection tests pest and disease identification, economic thresholds, integrated pest management (IPM), pesticide selection and safety, and resistance management in Nepal's rice, maize, vegetables and citrus.
Core rules
- Disease triangle: susceptible host + virulent pathogen + favourable environment. Management removes at least one leg; resistant varieties and sanitation are usually the most durable.
- Economic threshold level (ETL) is the pest density at which control prevents economic loss. It is not the same as the economic injury level (EIL), which is the break-even density.
- IPM combines monitoring, cultural methods, host resistance, biological control and judicious pesticides-pesticides are a last resort, not the first.
- Pesticide labels state active ingredient, formulation, pre-harvest interval (PHI) and re-entry interval. Always calculate product dose from active ingredient and treated area.
Worked example
A field of 0.5 ha needs a spray at 200 g a.i./ha using a 20% EC product. Active ingredient needed = 200 × 0.5 = 100 g a.i. Product needed = 100 ÷ 0.20 = 500 g (or 500 mL) of 20% EC. Reasoning: convert area first, then divide by formulation concentration; do not multiply by 0.20.
Traps
Treating ETL as a fixed national number; spraying prophylactically for blast or bacterial blight; confusing contact and systemic insecticides; and ignoring PHI before harvest.