गोभी वर्गीय फसलों का जैविक उत्पादन
Cole crops are a group in Brassicaceae that includes varieties of the species Brassica oleracea such as broccoli, cabbage, cauliflower, and Brussels sprouts found in the Mediterranean region. Cole crops are high in carotenoids, vitamins C and A, calcium, iron, magnesium, and contain synergrin alkaloid.
Isothiocyanates are biologically active compounds that are of considerable interest to farmers because of their ability to suppress some insects, diseases, nematodes, and weeds in a process known as biofumigation.
The number of crops in this family, their nutritional qualities, health benefits, compatibility in planting rotations, and pest suppressive qualities make these crops an excellent choice for many organic farmers.
Varietal selection for organic cultivation of Cole crop:
Factors influencing selection of varieties include market demands, disease resistance, suitability to production systems, and regional adaptability.
|Diseases/ pest||Resistant varieties|
|Black leg||Cabbage- Pusa Drum Head|
|Club root||Cabbage- Badger Shipper|
|Cabbage mosaic||Cabbage- Badger Market, Badger Ballhead|
|Sclerotinia rot||Cabbage- MR-1Cauliflower- Janavaon Ewawh, Pusa Snowball K-2 S|
|Black rot||Cabbage- Green Land Hammer, Pusa Muktha, MidoreCauliflower- Pusa Shubra, Golden Acre, late gaintBroccoli- Solo Head|
|Black spot or curd blight||Cauliflower- Pusa shubra|
|Cabbage butterfly||Cabbage- Green Acre, Red Rock, Red pickling|
Raised nursery beds of 2 x 1.5 m were prepared and 10 kg FYM was mixed in the soil. Seeds are sown in lines 5 cm apart and covered with 1 kg of vermicompost.
The main field was prepared with application of FYM at 8 t/ha. Vermicompost at 2.6 t/ha was applied in 2 splits at planting and 30 DAP.
Three foliar sprays of groundnut cake and vermicompost extract mixed with panchagavya were given 27, 35, and 42 DAP @ 1000 lit/ha. For this purpose, 1 kg of groundnut cake was soaked in water and to this 0.5 kg vermicompost was added next day and fermented for 1 more day. This was filtered and made to 10 liters. The requirement of groundnut cake and vermicompost was 100 and 50 kg/ha//spray, respectively. Panchagavya was prepared afresh each time by mixing 200 ml of cow urine, 200ml of milk, 200g ghee, pulp of 1 Robusta banana, along with 500 g of cow dung. The mixture was squeezed by hand, filtered through muslin cloth and made into 10 liters.
Phytozeal, an organic tonic, was sprayed 2 times @ 2.5ml/liter at 20 and 45 DAP in cabbage. Soil testing is recommended for application of proper dose manure and fertilizers.
Cultivation of legumes (Black gram/Green gram) and green manure crops (Sun hemp/ Dhaicha) as rotational crop and tomato as intercrop in the ratio of 8:2. Soil application of 5 kg/ha Azospirillium, Azatobactor, PSB, Molybdenum each and 10 kg/ ha Boron at the time of transplanting
Weed control :
Weed control is done manually by using small hand operated tools. The crop should be hand weeded twice at 20 and 40 days after transplanting.
Weed management before planting:
Weed control is easier and cheaper in fields that are not infested with difficult-to-control weeds. Problematic weeds include burning nettle, annual sowthistle, shepherd's-purse, London rocket, purslane, hairy nightshade, chickweed, and nutsedges. If problematic weeds are present in significant numbers, the best strategy is to rotate to a crop in which they can be successfully controlled. Planting date can have an impact on weed problems in a given region. For instance, fields planted between October 1 and October 15 in the southern regions are usually fairly weed-free.
Fallow: Sanitation is critical in a weed management program. Some weeds can produce thousands of seeds in a single season. To reduce seed production, disc or mow harvested fields before weeds flower and produce seeds. If weed species are present, cultivate areas around the field such as field edges, fence lines, roadsides, and irrigation ditches regularly to prevent weed seed production. Cultivation equipment and irrigation water must also be kept free of weed seeds and vegetative propagules to avoid spreading weed populations
Cultivation and bed preparation: Pre-plant ploughing followed by irrigation and one or two harrowing before bed formation, will destroy many weeds. Deep ploughing with MB plough can reduce the nut sedge population by 95 to 98%. Proper bed preparation is important for successful weed control after the crop is planted. Poorly leveled land will cause water to collect in low areas of the field, favoring growth of water-loving weeds. Effective cultivation of bed tops requires precise row spacing and careful alignment of cultivating tools.
Stale seedbed: The concept depends on controlling the final flush of weeds before crop emergence, followed by minimal soil disturbance to reduce subsequent weed flushes. To do this, prepare a seedbed and pre irrigate it to germinate weed seeds. Kill all emerged weeds just before the crop emerges and the crop can be direct seeded.
Weed management after transplanting:
Cultivation: Cultivation is one of the most effective post plant cultural practices that can be carried out at the critical stage of the plant. Effective cultivation of bed tops requires precise row spacing and careful alignment of cultivating tools. Direct-seeded Cole crops are frequently cultivated at about the two to three leaf stage and again 2 weeks later. The first cultivations remove early emerging weeds, and later cultivations cut out weeds that germinate later in the growth cycle. The goal of cultivation is to cut weed seedlings as close to the seed row as possible without disturbing the crop. More precise cultivation allows for reducing the width of the uncultivated band and thereby removing a higher percentage of the weeds. Uncontrolled weeds in the seed line are removed by hand or other mechanical means by the use of specific weeding implements such as finger and torsion weeders.
Hand hoeing: Hand hoeing is generally necessary in Cole crops. Cole crops are frequently transplanted as such there is generally no need for a thinning operation. However, weeds are usually removed by hand in the first 30 to 40 days after transplanting. Careful hand weeding is necessary at this early stage of the crop cycle because of the delicate stems of the crop. Depending on weed pressure, one or two subsequent hand weeding may be undertaken.
Integrated pest management in cole crop:
Diamondback moth (DBM), Plutella xylostella: Sow 2 rows of mustard for every 25 rows of cabbage. Mustard attracts 80-93% of DBM. Sprays of NSKE 4% at head initiation between 17 & 28 days after planting were found to be highly effective against DBM.
Sprays of neem soap and pongamia soap both at 1% help in reducing DBM, aphids and leaf Webber. Under natural conditions in an undisturbed ecosystem (insecticide-free environment), the parasitoid, cotesiaplutellae @ 50,000 adults/ha is capable of exercising about 70-80% control of DBM in India. ‘Biotrol’ WP (25X106 spores/mg) can be used. Application of 5 rounds of B. thuringiensis var.kurstaki @ 1kg/ha.
Cabbage butterfly (Pierisbrassicae): Mechanical removal of egg masses and gregarious larvae is effective. Spraying of Bacillus thuringiensis at 1kg/ha.
Tobacco caterpillar (Spodopteralitura): Destruction of egg masses and skeletonized leaves where young larvae are feeding gregariously. Spray of NSKE 4% early stage larvae. Large larvae have to be controlled by picking(use the sharp thick iron needle by piercing hole in head and killing).
|Organically Accepted Materials to Caterpillars||Commercial Products|
|Bacillus thuringiensis||Agree, Deliver, Javelin, Dipel, Xantari, Prolong, Britz BT Dust|
|Beauveria bassiana||Mycotrol, Naturalis, Botanigard|
|Neem||Neemix, Argoneem, Azadirect|
|Pyrethrin + Diatomaceous Earth worms||Diatect V|
|Garlic||Cropguard, Garlic Barrier|
Aphid (Lipaphiserysimi): Aphids pierce plants and suck their juices, distorting leaves and growing points. Large colonies infest leaves, heads, and flower stalks, making products unmarketable. Cauliflower intercropped with non-crucifer host plants like sunflower, tomato and marigold to reduce the aphid incidence and enhancing the number of natural enemies resulting in higher yields. Mustard as trap crop to attracts aphids or spray of NSKE 4%.
Integrated Disease Management in Cole crops
Damping-off (Pythium sp. Aphanidermatum sp., Rhizoctonia solani): Prepare well drained nursery beds, use of well decomposed organic manure, wide spacing between rows, lesser density of seedlings and light but frequent irrigations helps in reduction of damping off. Good control of damping off was obtained through soil incorporation of wheat bran preparation with T.harzianum in commercial nursery.
Seed treatment with Trichoderma spp. @ 4gm/kg to control the disease. Soil drenching with 0.6% Bordeaux mixture commencing 15 DAS and subsequent 2 more drenching at 10 to 15 days interval to control of this diseases.
Black rot (Xanthomonas campestris pv.campestris): Xanthomonas enters the plant at leaf margins or through wounds. Leaf margins develop yellowish patches that turn brown with black veins. The infection works its way down the leaves, leaving a "V" pattern in its wake.
This bacterium favors humid, rainy conditions, and is dispersed by the splashing of droplets of water. Hot water treatment of seeds at 500c for 30 minutes, drenching of seed beds with 1% bordeaux mixture, 3 years crop rotation with non-host crops and strict field sanitation will help in checking the disease. Rouging of diseased plants helps in reducing the disease incidence.
Crop rotation with rice was found to be best in reducing the black rot disease. B.subtilis used as seed treatment, seedling root-dip treatment and soil drenching.
White rot or stalk rot (sclerotiniasclerotiorum): Avoiding excess moisture with less frequent irrigation and reducing the plant population by following wider spacing will create micro climate less congenial for disease development.
Application of FYM or saw dust reduces the disease incidence. Follow cabbage/cauliflower- paddy rotation. Remove diseased leaves and destroy them. Soil application of T.harzianum and Aspergillus niger
Alternaria black spot and downy mildew (Alternaria brassicae and Peronospora parasitica):Small dark spots initially form on leaves, but later develop into tan spots with target-like concentric rings. When dried, these spots, resulting in a "shot-hole" effect.Prolonged periods of high humidity, cool temperature, and rain favor to its development cottony white masses, usually under leaves.
The tops of leaves develop purplish spots that later turn yellow or brown. Infected young seedlings may die, while cauliflower curd and cabbage heads may all become unmarketable. Seed treatment with hot water maintained at 500c for 30 min is effective.
Giving wider spacing of 60x50cm and removal of basal leaves from time to time helps to reduce the disease incidence.Seed treatment with T.viride and P.flourescens @ 4-5gm/kg andsoil treatment of nursery beds with neem cake enhanced the seed germination and seedling stand.
Club root (Plasmodiophora brassicae): As the fungus spreads it distorts and disfigures the roots, causing them to swell and crack, allowing secondary organisms to invade and aid in decay.
The disease is favored by acid soils; therefore, liming is recommended if the soil pH is lower than 7.2. Other methods to control clubroot include rotating out of Cole crops for a couple of years, having good drainage, and controlling brassica-type weeds. Cole crops vary in their susceptibility to clubroot, with cabbage, Chinese cabbage, are very susceptible while cauliflower and kohlrabi have medium susceptibility
Lalu Prasad yadav & Dr. Avtar singh*
*Senior scientist, Department of vegetable science
College of Agriculture. CCS, Haryana Agricultural University, Hisar (Haryana) 125004