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| AGRICULTURE TRIBUNE |
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Give old mango trees a new lease of life Let pesticides not harm you Herbicides: learn before you spray Disease-resistant rice developed
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Give old mango trees a new lease of life
MANGO, the king of fruits, is cultivated throughout India. In the South, Banganpali, and in the North, Dusehri, hold the place of pride at any dining table. Alphonso is an important cultivar with untapped export potential. Seedling plantations of “desi” mango varieties, the fruit of which is essentially “sucked out” rather than “eaten”, are still found in the countryside, where no commercial cultivars are grown. Mango is a huge tree: a single tree growing in the open can occupy up to an acre of land. It can bear fruit for 60 years. The yield may vary from a few kilograms to a ton, depending on the age and bearing capacity of the tree. There are reports that many seedling mango trees, which had been bearing good crop of high-quality mangoes for juice and pickle, are being uprooted and sold for wood across the region. The commercial plantations of grafted mango trees that have grown old and are not bearing good crop are also being replaced with new plantations. Dr K.K. Sharma, who retired from PAU, says orchardists can avoid uprooting inferior seedling trees and other low or non-bearing mango trees. He recommends the rejuvenation of old trees or top-working of seedling trees. For this, a tree should be beheaded keeping 30cm stubs on 3-6 major limbs from January 15 to February-end. Several sprouts will come up on these stubs during March-April. Let all these sprouts grow till September. Select the best one or two sprouts on each stub and graft them with the desired cultivar. Remove the rest of the sprouts gently by giving a clean cut close to the stub so that these may not re-sprout. If any of these shoots are left they will overpower the newly sprouted grafts. This way one will have 6-12 grafted shoots. These grafts sprout within 20 days of grafting. The shoot above the sprouted graft should be headed back by keeping only one whorl of old leaves in November. These leaves provide food to the newly sprouted graft. Newly sprouted grafts should be covered with basmati trash or plastic bags to save the grafts from frost or severe winters in December. The covers may be removed in February-March. While removing the covers, the polythene sheet used for tying the graft union should also be gently removed. The old sprout above the graft union should also be re-cut, keeping only the newly sprouted grafts. Care should be taken that grafts should not get damaged since these cannot tolerate even small pressure. For at least two years take care that no sprout should come up on the tree limbs other than the grafted shoots. Top-worked trees come into bearing within five years, depending upon the grafted cultivar. The old superior mango trees (dusehri-langra, etc) can also be rejuvenated similarly. In the rejuvenated trees, select 6-12 out-growing sprouts on the 3-6 stubs during June. Remove the rest of the sprouts. These selected shoots grow very fast. During August, the apex of the shoots may be pinched to check the fast growth. This will also help in the development of side branches. The land rendered open to sun after top-working can be utilised for growing crops till the trees come into bearing. With rejuvenation, the benefit of an established root system of the trees can be utilised profitably. These trees can bear a good crop for a number of years once more.
Precautions The following precautions should be taken in the process: A clean cut should be given to the limbs with a sharp saw to avoid bark splitting. Start beheading from base to the top. Apply bordeaux paste on the cut surface soon after beheading. Preparation of the paste: dissolve 2 kg of copper sulphate in 15 litres of water; mix 3 kg of quick lime in 2-3 litres of water and then add the remaining 12-13 litres of water; mix the two concentrated solutions. If the old trees are infected with fungi, do not behead the limbs since the stubs may not sprout. The Fruit Research Station, Gangian (Dasuya), of Punjab Agricultural University, Ludhiana, has to its credit a collection of 70 promising “sucking” mango selections and 10 grafted table varieties. PAU has recommended seven “sucking” mango selections (Gn 1 through Gn 7). Table-mango cultivars recommended are dusehri, langra, chausa, alphonso and amrapali. The grafted mango plants come into bearing within five years, whereas seedlings take 7-10 years. |
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Let pesticides not harm you PESTICIDES are an important tool for pest control in most situations like protection of plants, stored foodgrains, household articles, domestic animals and even human beings. Even in integrated pest management pesticides have a major share, though the use of other control methods like biological control agents and bio-pesticides is on the increase. Synthetic pesticides are popular because of the ease of application, effectiveness and high economic returns. Being poisonous in nature and harmful to human beings and other creatures, pesticides should be used with care purchase onwards. Purchase At the time of purchase, select the pesticide according to the recommendations of competent authorities. According to the Insecticides Act, 1968, certain information is mandatory to be given on the label of the container. These include technical and trade names of the pesticide, composition (percentage of active ingredient and other auxiliary materials), manufacturer’s address, registered uses, designation of the toxicity class, net contents, date of manufacturing and expiry, etc. Purchase the insecticide by trade name. For example, if you want to purchase endosulfan, which is a technical name, ask for Thiodan, Endocel, etc., rather than for endosulfan. Do not purchase pesticides after their expiry date. Before use After the purchase, read the label information carefully. The toxicity label is in a diamond shape, divided into two triangles. The lower triangle is red/ yellow/ blue/ green; these colours depict the toxicity class, red being extremely toxic, followed by yellow, blue and green. The handling of the red-label pesticides needs utmost care. One should not work alone while handling the extremely toxic pesticides. Store the pesticides in labelled containers out of the reach of children. Check the spray equipment by filling water and rectify the problems. During use While opening the packing, take care not to blow or splash the contents. Use only the recommended dose as a higher dose, besides being costly, can also cause phytotoxicity, residues and other health hazards. On the other hand, a lower dose will not be effective. Mix the pesticide in a ventilated place to avoid inhalation. Do not mix in containers meant for general use. For mixing, use rod and never bare hands. Do not use your mouth to siphon pesticide out of a container. Those handling pesticides should not be sick or have any bruise or cut. Wear protective clothing while using pesticides. Do not eat, smoke or chew during the spraying operation and never rub the mouth or eyes with your hands while spraying. Do not spray against the wind, as it will cause drift, leading to harmful effect to non-target organisms, and the wastage of pesticide. Never apply granules with bare hands as these formulations are highly toxic and are absorbed through the skin. Generally, with packs containing granules, gloves are provided; if not, then wear synthetic gloves and use a granule applicator. The risk of skin absorption is increased in warm weather when sweating. Also, people tend to avoid protective clothing in such weather. Do not use your mouth to blow open clogged nozzles, instead use a fine wire. When there is bee activity in the field, avoid pesticide application. But if necessary, then do it late in the evening when there is no bee activity. Most ready-to-use formulations are inflammable; do not bring these near a flame. After use, clean the spray equipment thoroughly with water. The unused pesticide should be kept in a labelled container. Do not use empty pesticide containers for any purpose, particularly for storing water or feed for animals. The containers should be destroyed and buried. Wash hands thoroughly with soap, take a bath, and change your clothes. After application of the pesticide, observe the waiting periods recommended for different pesticides before harvest. |
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Herbicides: learn before you spray IMPROPER spray of herbicides, besides giving poor control of weeds, may also lead to herbicide resistance in the target weed. The application of herbicides thus requires special attention because the target and the host belong to the same class, whereas in the case of insecticides and fungicides they belong to different classes. In herbicides, accuracy and uniform application are very important, besides using adequate quantity of water and the recommended rate of herbicide because the gap between crop injury and weed control failure is very small. Wild canary grass, (Phalaris minor Retz.) one of the grassy weeds in wheat, has become resistant to isoproturon in most parts of Haryana and Punjab. Isoproturon, a substituted urea herbicide, has been withdrawn from the resistance-affected area in Haryana and four new post-emergence herbicides have been recommended for the control of Phalaris minor. This resistance to isoproturon is also due to improper application of isoproturon through urea or sand mixing, termed as broadcasting. The point of concern now is the improper spraying of the newly recommended herbicides like sulfosulfuron, clodinafop, fenoxaprop and tralcoxydim. It is seen that more than 70 per cent farmers apply herbicides the way they apply insecticides in paddy and cotton, spraying with flood-jet nozzles directed upwards and swinging the lance while spraying. Farmers use knapsack sprayers, which require continuous hand pumping and are generally fitted with a single-nozzle lance and a variable cone nozzle. Spray nozzles come with various spray patterns like flat fall, even fall, variable cone, flood nozzles and hollow-cone nozzles. Flat-fall nozzles are used for herbicide spray, which can be used on a multiple-nozzle boom to increase the efficiency. Farmers generally use a single nozzle, which consumes more time in spraying the herbicide with adequate quantity of water. Using multiple-nozzle hand booms will not only save time but also give a more uniform spray pattern. Application of herbicides requires a flat-fall nozzle. The tapered pattern from the centre to the edges requires 30 per cent overlapping with every pass for an 80° flat-fan nozzle spaced 50 cm apart and the boom height must be 43-48 cm from the target. For a 110° nozzle spaced 75 cm apart, the boom height should be 50-55 cm. Spacing of nozzles is important to overlap the spray pattern and give uniform coverage. A higher boom height results in drift while a lower height may cause crop injury and may leave strips unsprayed between two nozzles. Farmers prefer flood jet nozzles because of the bigger droplet size and higher output, which saves time. But the same can be achieved by using a multiple-nozzle boom fitted with flat-fan nozzles. Pressure variation in the tank with the up and down strokes is another reason for improper spray. Constant pressure regulator valves should be fitted before the nozzles to ensure a uniform spray. Nozzles available in the market generally come without pressure regulator valves and strainers. A damaged nozzle may lead to erratic spray patterns, thus a worn-out nozzle must be replaced. Improper spray of herbicides can either cause crop injury or fail to give satisfactory weed control. It may also lead to spray drift, which can play havoc with adjoining sensitive crops. Spray tanks must be cleaned before moving to the next crop. Residues of some of the herbicides like 2,4-D can destroy certain broad-leaf crops like cotton. Mixing of surfactants is very important where they come in separate packets, as in the case of sulfosulfuron. Surfactants help the herbicide to bind, penetrate and spread uniformly. |
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Disease-resistant rice developed HYDERABAD: Applying DNA-marker technology, the Centre for Cellular Molecular Biology (CCMB) and the Directorate of Rice Research (DRR) have developed bacterial leaf blight (BLB)-resistant Samba Mahsuri and Triguna rice lines in a unique collaborative effort. At a press conference last week, DRR Director B. Mishra said that BLB was one of the serious production constraints of rice in India, limiting the yields by more than 15 per cent in endemic areas like Punjab, Haryana and western Uttar Pradesh. He said Samba Mahsuri was a premium rice variety of Andhra Pradesh. Triguna, another rice variety, grown in certain areas of Andhra Pradesh, was resistant to pests like brown plant hopper, but susceptible to BLB, he explained.
— UNI
Vanilla in Karnataka BANGALORE: With the production and demand gap increasing by 10 per cent every year and the crash in coffee prices, farmers in Karnataka are attracted to vanilla cultivation. According to official sources here, the aggregate demand for processed vanilla beans globally was around 4,000 to 5,000 tonnes. Crash in coffee prices also has forced the farmers to vanilla cultivation, the second costliest spice after saffron, the sources said.
— UNI
Micro-irrigation ANAND (Gujarat): The total land area under micro-irrigation in India has almost touched the 5-lakh hectare mark, which has propelled it to the top five nations in the world having the maximum area under micro-irrigation, said a study by the International Water Management Institute (IWMI) at Anand. A paper on this aspect was presented last week during the third annual IWMI-Tata Partners Workshop held here. According to the study, micro-irrigation in India has increased almost twofold from the previous figures recorded in 1994-95. In India, Maharashtra tops with 46 per cent of land under micro-irrigation.
— UNI
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