| Package of Practices for Cashew cultivation in Goa |
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Cashew (Anacardium occidentale L.) which was introduced in Goa by the Portuguese in the 16th century, mainly to control soil erosion and to use in afforestation programmes has now become an important cash crop of Goa. It is grown in an area of 47,094 ha which comes to 30 percent of the total cultivated area. Goa has more land under cashew than any other state. Although there has been significant increase in the area under cashew since liberation (13,513 ha in 1961), there has been no significant increase in the productivity. The average yield is around 1.5 kg nuts per tree which is quite low as compared to other states. The estimated production of raw nuts is about 11,310 tonnes which is insufficient to meet the requirement of about 13 cashewnut processing factories having 20,000 tonnes capacity. At the national level, cashew area has increased from 1.10 lakh ha (1955-56) to 6.37 lakh ha (1987-88) with the production increase from 79,000 to 2,60,000 tonnes. However, the current production is not sufficient to meet the requirement of cashew processing industries with processing capacity of more than 4.5 lakh tonnes of raw nuts. Therefore it became imperative to increase the production of cashewnut by adopting extensive and intensive methods, within the shortest time. Lack of conscious efforts to plant selected high yielding varieties and leaving the crop to nature's care has been the major factor for the low production in the state. Of late, growers are convinced of the need to adopt package of practices to step up productivity and production of cashew plantations. The package of practices suggested in this bulletin would go a long way to augment overall production of nut and cashew apple in the state. The agroclimatic situation in Goa offers good scope to raise successful cashew plantation in varied soils ranging from coastal sandy to sandy loam and laterite soils in the hill slopes upto an elevation of about 700 mt. Although cashew can adopt itself to wide range of soil conditions, it suffers in the soils with prolonged water logging. Extreme low temperature and frost are also not conducive to raise plantations. There is scope to extend cashew cultivation in the wastelands identified by the land survey department of the state. Till recently there were no distinct high yielding varieties of cashew. Today several cashew varieties are evolved which are capable of giving 20 kg yield of raw nuts per tree per year as against the average yield of 1.5 kg per tree per year of local cashew trees in Goa. Therefore, planting of high yielding varieties is a must for attaining high productivity levels. Out of the several varieties released so far, following varieties are observed to be performing well under Goa conditions. Venguria - I : This variety gives an average yield of 15 kg nuts per tree per year at the age of 10th year. The size of the nut is medium (160 nuts/kg) with a shelling percentage of nearly 31. The size of apple is medium with yellow colour. Venguria - 4 : This variety yields about 20 kg nuts per tree per year at the age of 12th year. The size of the nut is medium ( 140 nuts/kg ) with shelling percentage 31. The apple is medium to small in size and red in colour. A survey was undertaken by this Institute to identify in the state high yielding cashew trees with bold nuts and big size apple and the clones of about 10 selections are under evaluation. Until recently, cashew was propagated only through seeds. Cashew being a cross pollinated crop, there is a wide variation in nut and apple characteristics as well as yield in seedling progenies. It also takes about 5-6 years for first bearing when propagated through seeds and hence should be discouraged. Vegetatively propagated planting material is necessary to obtain higher and early yield. Many techniques of vegetative propagation like grafting, budding and layering have been tried in cashew with varied degrees of success. Amongst different vegetative methods of propogation tried so far, soft wood grafting has been found suitable under Goa conditions, giving 60 % success. Soft wood grafting Following steps should be followed to obtain better success with soft wood grafting in cashew. (a) Raising seedlings for rootstock : Collect uniform cashew seednuts during the peak period of harvest i.e. February to April, preferably from high yielding uniform cashew trees.Select the seeds with high specific gravity ( 1.025 to 1.05) to get quick germination and to obtain vigorous seedlings with healthy shoots. In order to identify the weighty seed nuts, immerse the seed nuts in 10% saline solution, reject the floating nuts and select the nuts which are settling at the bottom for sowing. Prepare polythene bags of 30 cm x 20 cm size of 300 gauge thickness and punch 15-20 holes on the bag. Fill the bag with potting mixture 2:1:1 (soil: sand: compost) upto the brim leaving I" of gap at top. Add 5 g of Mussorie Phosphate per bag, which can be mixed with the soil mixture at the time of preparation. Sow the seed nuts, stalk end up, 2 to 2.5 cm deep in the centre of the filled polythene bag. To hasten the process of germination, the seed nuts can be soaked overnight in water before sowing. Water the bag immediately after sowing and everyday in the morning. Seednuts usually germinate within 15-20 days after sowing. The seedlings will be ready for soft wood grafting in about 30-40 -days after germination. Select healthy vigorous seedlings having tender flush, for grafting (with four developed leaves). Spray insecticides like Nuvacron, Rogor, Endosulfan and Malathion at the rate of 1.5 ml/litre of water to control leaf damaging insects. (b) Selection of scion : Scion should be selected from high yielding mother trees preferably from the trees of proven performance. The selected scion shoot should be 8-10 cm long, straight, round, of pencil thickness and brown coloured having dormant plumpy terminal bud. The selected scion should be precured by clipping off leaf blades, leaving behind petiole stubs, about a week prior to its detachment from mother plant for grafting. (c) Grafting procedure : Remove the leaves from the top portion of the seedlings, keeping one or two mature leaves at the bottom. Give the transverse cut at the top of the seedling and remove the terminal shoot and make a cleft of 3-4 cm deep in the middle of the decapited stem of the' seedling by giving a longitudinal vertical cut, on the soft portion of stem. Mend the scion into a wedge shape of 3-5 cm long by chopping off the bark and little wood from two opposite sides, taking care to retain some bark on remaining two sides. Insert the wedge of the scion into the cleft of the stock seedling, taking care that the cambium layers of the stock and scion come in perfect contact with each other. Cambium is a thin layer of cells in between the bark and the wood seen as a line on close observation. Tie the graft joint firmly with 1.5 cm wide and 30cm long polythene strip of 100 gauge thickness. After-care of the graftKeep the newly grafted plants under shade and humid conditions. Sprouting of the terminal bud will be seen after about 15-20 days. Water the grafts as and when required depending upon the season and weather conditions. Any sprouts observed on the rootstock portion below the graft joint should be removed at frequent intervals. Remove the polythene strip from the graft joint about 3 months after grafting, to avoid girdling. Shift the grafts from one place to another or just lift the grafts and keep at the same place once in amonth, to prevent them from striking roots into the ground. Inorder to avoid this shifting work, grafts may be kept on polythene sheet ( I m wide,1000 gauge ). Protect the grafts from pests and diseases as and when they are noticed. Spray endosulfan / Nuvacron @ 1.5 ml/litre of water to control pests at weekly intervals and drench the bags with bavistin ( 4 goitre of water ) to control leaf diseases just before grafting and afterwards at 15 days intervals till the grafts are well established and grown. June to September is ideal period for soft wood grafting in Goa, recording about 60% success during these months. Top working One of the major reasons for low yields of cashew in Goa is that most of the plantations have been established from seedlings. Adoption of improved practices like manuring and timely plant protection measures would no doubt increase the yield to a certain extent, but raising the level of productivity is possible either by grubbing out the trees which are poor yielding and replanting with grafts of high yielding varieties or by rejuvenating the unthrifty trees by " top working ". Sentimentally, removal of healthy trees eventhough they are poor yielders, is not acceptable to many growers and therefore " Top working " is a better solution to raise the level of productivity of unthrifty cashew trees. Top working is nothing but substituting the crown of the tree with the shoots of high yielding 'nature, taking advantage of the well developed root system, to improve the productivity of poor yielding cashew tree which are otherwise quite healthy. This procedure is generally successful only with trees which are about 10 year or less. Procedure for Top working ' : First, mark the trees which are yielding low ( less than 2 kg/tree ) and which are to be top worked. Cut such tree at the height of 0.75 to I m from the ground level with the help of saw, axe or koyta, in the month of April-May. While beheading the tree, take care that the cut is smooth and bark does not split. Soon after the beheading, seal the cut surface with melted paraffin wax. Swab the stump with B.H.C. 50% solution. Apply 250 gm of BHC 10% to the soil around the stump, upto a radius of I m. A periodical treatment at fortnightly interval till the onset of monsoon is desirable to check the borer attack. Depending upon the vigour of the stump, 20-80 new shoots emerge out from each stump within about two months from the date of beheading. Select 6-8 vigorous shoots and graft them with the scions collected from high yielding variety, by using soft wood grafting technique, during July-August. Die-back of the shoots may occure during monsoon. This can be checked by spraying either Bavistin (o) 20 gm/101 of water, or I % Bordeaux mixture, at fortnightly interval. Also spray Rogor / Nuvacron ( 1.5 ml/litre ) to the sprouts to keep away insects damaging the new leaves. On securing about 4-6 grafts on each stump, the remaining nongrafted shoots can progressively be clipped off, taking care that the bark of the stump is not exposed to the heat of the sun. The. successful grafted shoots should be provided with support by fixing the shoots with jute thread to avoid lodging and damage by heavy winds. Care should be taken to provide shade to the stump to prevent sunscorch, either by covering with straw or by white washing with lime. The trees beheaded in April-May and grafted in July- August will start yielding from the fruiting season of subsequent year. The newly planted grafts take two to three years to attain a sizeable canopy. But the top worked trees attain a sizeable canopy and start yielding in one year, because of the well established root system of the stock. Hence, rejuvination of low yielding cashew trees by top working is possibly the best technology for boosting existing unthrifty young plantations in Goa. Clear the land from bushes and other trees well before the pre-monsoon showers. As soon as the premonsoon showers are received, dig pits of 60x60x60 cm size at a distance of 8 x 8 m. Fill the pit completely with top soil, half kilo sterameal, half kilo Mussorie Phosphate and one basket of compost or farm yard manure. Add 100 gm of BHC. 10% to each pit before planting, to check the attack of white ants. Immediately after the onset of monsoon, plant the graft in the centre of the pit and support it by using pegs. Planting should be completed before June end, to take full advantage of the prevailing monsoon rains. Wherever irrigation facilities are available, it is advisable to plant the grafts in March and irrigate them so that by June the grafts are well established in the field. Cashew is usually grown in poor soils but it responds well to fertilization. A fertilizer dose of 500 g N, 125 g PzOs and 125 g K,O per tree per annum is recommended for Goa. The details of the manurial requirement for different age groups are given in the table 1. The fertilizer may be applied half in June and half in August or if the first application is delayed due to some reason, the full dose may be applied in August. For applying fertilizers, basins should be opened leaving 25 cm from the trunk, 10-15 cm deep and to a radius of 1- 2 m, depending upon the canopy of the tree. Fill the basins with the green leaves and add the recommended quantity of chemical fertilizers and cover it with the soil. The best way is to grow dhaincha (green manuring crop) in the month of June immediately after the onset of monsoon which can be cut and used a green manure in the month of August. Manurial requirement of cashew in Goa.
During the first year of planting, cashew grafts should be irrigated once in fifteen days during summer months. About 10-15 I of water should be given at a time. Mulching of basins with straw or dried leaves would help in conserving moisture and also prevent weed growth. Though cashew can come up well and yield under rainfed condition, it gives good response to irrigation. Cashew cannot withstand water stagnation or flooding. In the places where such problems exist, adequate drainage should be provided during monsoon. IntercultureInterculture in cashew orchard is necessary for the proper upkeep of the plantation. Cashew garden should be kept free from weeds as they compete for nutrients and moisture. Growing of green manuring crop dhaincha in June reduces the weed growth to a greater extent. Weeding can be done manually or by spraying weedicides. Since labour is costly and scarce in Goa, it is advisable to go for chemical weed control. Spray Gramaxone @ 50 ml for 101 of water on emergence of weeds. Since it is non selective weedicide, care should be taken to see that the weedicide does not fall on leaves of cashew trees at the time of spraying. When cashew is grown on slopy land, soil erosion and leaching of plant nutrients are generally experienced. Therefore, terracing may be done by cutting the elevated portion of the slope and spreading the soil to the lower side. Such a type of terracing also helps in conserving the rainwater and increase subsoil moisture. Contour trenches across the slope are also beneficial in slopy lands. Since cashew is grown on hill slopes and most of the plantations are rainfed, intercrops can be grown only in rainy season. It is advisable to grow leguminous crops like cowpea, mung, udid, tur and groundnut in rotation with the vegetables like bhendi, amaranthus, chillies, cucurbits etc., to get income during the juvenile period of plantation. Ragi, tapioca, and local varieties of pineapple can also be grown successfully as intercrops in cashew orchards. Cinnamon (Tiki) is also suitable as intercrop if grown as a small bush in between cashew trees. Cashew tree exudes gum resin from the cut ends and therefore regular prunning is not advisable. In the initial stages prunning may be done for giving proper shape to the plant. In the adult plantation, the dried and criss cross branches may be removed with minimum damage to the plant in alternate years. Prunning helps the plant to take good shape and it makes the cultural operations easy. It is advisable to remove all branches to a height of 3' from base during the initial years to keep a clear straight trunk for easy cultural operations. Systematic plant protection schedule should be followed to get steady returns from cashew plantations. Of the several insect pests reported to infest cashew in Goa, the tea mosquito and the cashew stem and root borer are of major importance. The production loss from a single pest, the tea mosquito, alone is estimated to be about 30 percent. Cashew stem and root borer is yet another pest responsible for killing 5-10 percent of productive trees. Tea mosquito ( Helopeltis antonnii ) Tea mosquito is a serious pest of cashew in Goa. The adult is a reddish mirid bug which usually appears at the time of emergence of new flushes. The nymphs and adults suck the sap from tender shoots, leaves and inflorescence and even immature nuts and apples. As a result, the shoots and other inflorescence dry up. The tender fruits and immature nuts develop erruptive spots and they finally shrivel up. The pest can be easily controlled by spraying 0.05 % Endosulfan ( 15 ml in 101 of water ). Three sprays should be given for complete control of the pest. The first spray of Endosulfan should be given in October-November when the new flushes emerge, second of systemic insecticide like Monocrotophos amd Dimethoate in Dec-Jan during emergence of inflorescence and followed by third spray of Endosulfan in February at the time of fruit set. Stem and root borer ( Placaederus ferrugineus L. ) This is a serious pest of cashew and is capable of killing the tree outright. The adult is medium sized, reddish brown longicorn beetle, the head and thorax of which are dark brown or almost black. The female lays eggs into the crevises of loose bark in the trunk or the exposed portion of the roots of cashew trees. The grubs that hatch out bore into the bark and feed on the soft tissues. The attack could be identified by presence of small holes in collar region, gummoses, extrusion of chewed up fibres and excreta and discolouration of bark. If no control measures are taken up, the leaves start yellowing followed by drying of branches and finally resulting in the death of the tree. It is very difficult to control the pest in the advanced stage. Therefore, control measures should be taken up at early stage of infestation. For effective control of the pest, swab the trunk of the tree with coal tar and kerosene (1:2) upto one metre height from the ground. Treat the soil with 500 g BHC 10 % to a radius of 45 cm. The trees showing the severe infestation should be removed alongwith roots and burnt. Heaping the organic waste around the trunk should be avoided. Fruit and nut borer ( Thylocoptila panrosama M. ) It is a pinkish dark actively moving caterpillar which bores into the tender apples and nuts. Nuts are damaged in case of severe infestation. The caterpillars attack the fruits at all stages and cause the shrivelling and premature fall of nuts. This pest can be effectively controlled by spraying 0.05 percent Endosulfan. The other minor pests of cashew include, leaf minor (Acrocercops syngramma M ), leaf and blossom webber ( Lamida moncusalis Walker ), shoot tip caterpillar ( Bypatima haligramma M ) and leaf flower thrip ( Scirtothrips dosatis Hood ). As compared to the number of pests attacking cashew and intensity of damage caused by them, the magnitude of the disease problem is rather comparatively low. Among few diseases attacking cashew, die-back and damping off of seedlings are found to be most destructive. Die-back or pink disease: This is a fungal disease caused by Corticium salmonicolor which occurs in the rainy season. The affected branches show white or pinkish growth on the bark. The fungus penetrates into the deep tissues and causes gradual death of the shoots. In advanced stages, the bark splits and peels off. The leaves turn yellow and fall off giving a barren appearance to a tree. For effective control of the disease, prune all the affected branches below the spot of injection and destroy them. Protect the cut surface by applying Bordeaux paste. The disease can be prevented by giving prophylatic spray of 1% Bordeaux mixture twice a year, first in May-June before the onset of monsoon and second in October. Damping off of seedlings: It is a fungal disease caused by Fusarium sp., Pythium sp., Phytopthora palmivora and Cylindrocladium scoparium and affects the cashew seedlings in nursery. The fungi attacks either the collar region or the root zone of the tender seedlings causing severe loss at the nursery stage. The disease incidence is severe in nursery where drainage conditions are poor. Therefore, adequate drainage should be provided during the rainy season. The disease can be controlled by drenching the bags with 1% Bordeaux mixture. Harvesting of cashew is done generally from March to May. Fully matured apples are allowed to drop down naturally with the attached nut. Then the nuts are seperated from the apples. Nuts are sundried for 1-2 days and stored before selling off in the market. Juice should be extracted from the apple within 24 hrs before the rotting sets in. Juice is usually extracted bycrushing the apple with the help of feet or wooden logs. Now a days machines are also available for extracting juice from the apples, and to prepare ' Feni ' a popular drink of Goa. An amount of Rs. 2,500/- is required to maintain one hectare of adult cashew plantation; on an average yielding around 1.0 tonnes/ha of raw nuts. As per the present market rates one tonne of raw cashew nuts would fetch about Rs. 20,000, by sale of nuts alone. The income realised by sale of apples would amply meet the cost of cultivation for one hectare. Preparation of one percent Bordeaux mixture For preparing one percent Bordeaux mixture, dissolve one kilo of powdered copper sulphate in five litres of water and one kilo of lime in another five litres of water separately in two plasic containers. After completely dissolving the contents, both the solutions can be poured simultaneously into another container through a strainer. To this, add 90 litres of water and stir well. To tesi for excess acidity in the Bordeaux mixture solution, dip a clean iron knife and if red coppery coating appears on the knife, add more lime till such coating does not occur, to make the solution neutral. For preparing Bordeaux paste, dissolve one kilo of copper sulphate and one kilo of lime in ten litres of water. Rest of the procedure is same as that of Bordeaux mixture. Note : The Bordeaux mixture or paste should be used on the same day. Therefore, prepare only the required quantity for the day.
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