(a) Describe the principles, components and strategies for Integrated Disease Management in crops. Write down its application in…

(a) Integrated disease management: principles, components, strategies and applications

Principles: prevention and exclusion of the pathogen, monitoring of disease and weather, use of economic thresholds, combination of compatible tactics, minimum harm to the environment and to natural enemies, and farmer participation.

Components and strategies: cultural (clean seed, sanitation, rotation, balanced nutrition, planting date); resistant varieties; biological agents (Trichoderma, Pseudomonas fluorescens); physical methods (solarisation, hot water); and need-based, rotated chemicals as the last resort.

Rice blast (Magnaporthe oryzae): grow resistant varieties (for example Pusa Basmati 1637); use clean seed and treat with Pseudomonas fluorescens or carbendazim; avoid late sowing and excess nitrogen (apply in splits); destroy stubble and alternate grass hosts; and spray tricyclazole (0.6 g/L) or isoprothiolane when leaf blast appears, repeating at booting for neck blast.

Bacterial blight of pomegranate (Xanthomonas axonopodis pv. punicae): plant disease-free material; prune and burn infected twigs and apply Bordeaux paste to cuts with disinfected tools; avoid overhead irrigation and injuries; adopt proper bahar timing; and spray streptocycline (0.5 g/L) with copper oxychloride (2.5 g/L) at intervals during humid weather, with soil-applied Pseudomonas in the root zone.

(b) Guava cultivation package

Soil and climate. Hardy; grows on light to heavy soils with good drainage and pH 4.5–8.2, in tropical and subtropical climates with 100–150 cm rainfall, at 15–30°C; frost harms young plants.

Propagation. Vegetatively: air layering (clonal), stooling, inarching and patch budding or wedge grafting on seedling rootstock; micropropagation is also used.

Varieties. Allahabad Safeda, Lucknow-49 (Sardar), Lalit (pink flesh), Shweta, Arka Amulya, Hisar Safeda and Pant Prabhat.

Bahar treatment. The tree flowers three times: Ambe (February–March flowering, rainy-season fruit), Mrig (June–July flowering, winter fruit) and Hasta (October flowering, spring fruit). The rainy crop has poor quality and heavy fruit-fly damage, so the winter Mrig bahar is preferred by withholding water in April–June, root exposure and light pruning to induce leaf fall, while deblossoming sprays (urea or NAA) remove the Ambe flowers, followed by manure and irrigation.

Disease management. Wilt (Fusarium oxysporum f. sp. psidii): healthy planting material, resistant rootstock, organic manure with Trichoderma, drench carbendazim; anthracnose and fruit rot: pruning and copper fungicide sprays.

(c) Round-the-year marigold cultivation

Varieties. African marigold (Tagetes erecta): Pusa Narangi Gainda, Pusa Basanti Gainda, Arka Bangara; French marigold (T. patula): Pusa Arpita.

Sowing and transplanting. Raise nursery seedlings in three seasons to give flowers throughout the year: rainy season (seed June–July, transplant July–August), winter (seed September–October, transplant October) and summer (seed January–February, transplant February–March). Transplant 30–35-day seedlings at 45 × 45 cm.

Diseases. Damping-off (seed treatment with thiram or captan, Trichoderma, drench), Alternaria leaf spot and flower bud rot (mancozeb), and powdery mildew (wettable sulphur).

Value addition. Loose flowers and garlands for religious use; lutein and xanthophyll extraction for poultry feed and nutraceuticals; essential oil and natural dyes; and use as a trap crop against nematodes, with careful grading and packaging for shelf life.