(a) What do you mean by "Economic Injury Level" (EIL) and "Economic Threshold Level" (ETL) ? Describe their roles in classifying…

(a) Economic Injury Level, Economic Threshold Level and pest classification in IPM

The Economic Injury Level (EIL) is the lowest pest population density that causes economic damage, that is, where the loss prevented equals the cost of control. The Economic Threshold Level (ETL), or action threshold, is the density at which control must be started to prevent the rising population from reaching the EIL. ETL is therefore set below EIL, leaving time for control to act. Both depend on crop value, control cost, crop stage and the damage per pest, and examples are the ETL for cotton bollworm and for rice yellow stem borer.

Role in IPM: ETL is the decision rule that replaces calendar spraying, so treatment is applied only when needed, reducing cost, residues and harm to natural enemies. Pests are classified by their General Equilibrium Position (GEP), the average population density over time, relative to EIL:

Key pests have a GEP near or above the EIL and cause regular economic damage unless controlled, such as cotton bollworm and rice stem borer. Occasional pests have a GEP below the EIL but cross it from time to time through weather or management disturbance. Potential pests have a GEP far below the EIL and become serious only if the ecosystem is disturbed, as when natural enemies are killed by pesticides. Migratory pests, such as locusts, invade from outside.

(b) Importance of fruit cultivation, and horticulture in poverty alleviation and nutritional security

India is the second largest fruit producer after China and the leader in mango, banana, papaya and lime. Fruit crops give higher returns per hectare than cereals, use wasteland and rainfed areas, support processing industries and earn export income. Horticulture output has exceeded foodgrain output since the early 2010s.

Poverty alleviation: fruit orchards give small and marginal farmers high net returns from small holdings; they create year-round labour in nursery raising, orchard management, harvesting, grading, packing and processing, much of it for women; and they build rural enterprises through value addition, such as pulp, juice and dried products. Orchards on degraded land in tribal areas, as under wadi programmes, give lasting incomes.

Nutritional security: fruits supply vitamins A and C, folate, minerals such as potassium and iron, antioxidants and fibre, and so address 'hidden hunger', anaemia and micronutrient deficiency, and diversify cereal-dominated diets. Support comes from the Mission for Integrated Development of Horticulture and from state horticulture missions.

(c) Protected cultivation: problems and prospects compared with open cultivation

Protected cultivation is growing crops under structures that modify the microclimate, such as greenhouses, naturally ventilated polyhouses, shade-net houses, insect-proof net houses, low tunnels and walk-in tunnels, for light, temperature, humidity and pests.

Prospects: year-round and off-season production at premium prices; yields several times those in open fields for crops such as capsicum, tomato and cucumber, and high-value cut flowers; efficient use of water and fertiliser through drip and fertigation; fewer pest losses and pesticide use; disease-free nursery and hybrid seed production; and independence from weather and suitability for cold or arid areas. Government subsidy under MIDH adds to the viability.

Problems: high initial investment and running cost, especially energy for cooling and heating in fully controlled houses; shortage of trained labour and technical know-how; heat build-up and high humidity favouring whitefly, mites, powdery mildew and soil-borne diseases and nematodes; salt build-up in the soil; poor marketing and cold-chain links; and limited availability of structures and equipment.

Compared with open cultivation, which needs little capital and is simple but exposed to weather, pests and seasonality with lower and variable yields, protected cultivation gives higher and more uniform, quality produce but suits high-value crops and farmers able to manage capital and skills.