Plant Protection and Pest Management: IPM and Safe Pesticide Use
This domain tests integrated pest management, the economics of spraying, pesticide formulation arithmetic, and the diagnosis of insect, disease and weed problems.
Core concepts
- IPM combines resistant varieties, cultural methods, mechanical traps, biological agents and chemicals as a last resort.
- Economic threshold level (ETL) is the pest density at which control measures should be applied to prevent reaching the economic injury level; EIL is the density where damage equals the cost of control.
- The disease triangle requires a susceptible host, a virulent pathogen and a favourable environment; removing any one prevents an epidemic.
- Selective herbicides: 2,4-D is a translocated synthetic auxin that kills broadleaf weeds, so it is unsafe near cotton and other broadleaf crops.
Worked example
A recommendation says 500 g a.i. per hectare of a 50% wettable powder. Product needed = 500 ÷ 0.50 = 1,000 g, that is 1 kg per hectare. If the sprayer applies 500 litres of water per hectare, product per litre of water = 1,000 g ÷ 500 L = 2 g/L. Filling a 16-litre knapsack then needs 32 g of product.
Traps
- Using the product dose and the active-ingredient dose interchangeably.
- Mixing up ETL and EIL definitions in one-line answers.
- Forgetting the waiting period between the last spray and harvest.
- Describing Bordeaux mixture loosely. A 1% preparation is 1 kg copper sulphate plus 1 kg lime in 100 litres of water.