Home Fruit Science High Density Plantation of Apple

High Density Plantation of Apple

810
high density plantation-apple

Introduction:

Apple is the most important temperate fruit crop of the North Western Indian Himalayan region. It is fourth among the most widely produced fruits in the world after orange, banana and grape. China is the leading apple producer in world. In India, it is grown in Kashmir, Himachal Pradesh, hills of Uttarakhand. Apple cultivation also extended to Nagaland, Sikkim, Arunachal Pradesh and Meghalaya. India’s share in the total apple production of the world is only 2.0 %. In India, total area under apple cultivation is 250 thousand hectare producing 1470 thousand MT fruit with productivity of 5.9 tonnes/ha. In Jammu and Kashmir, total area under apple is 90.1 thousand hectare with production of 909.6 thousand MT. The state of J&K leads the other apple producing states in India, in terms of productivity with production of 10.1 MT fruits per hectare. 

So, there is enormous scope for improvement of apple productivity through introduction of improved cultivars, replacement and rejuvenation of old and senile orchards. Low productivity of apple orchards in the district can also be attributed to inadequate proportion of pollinizers, lack of pollinators, poor canopy management and incidence of other diseases and pests. 

Low productivity of apple orchards in the district can also be attributed to inadequate proportion of pollinizers, lack of pollinators, poor canopy management and incidence of other diseases and pests. 

Climate

Temperature is one of the most important factors affecting apple cultivation. Most apple cultivars have a chilling requirement of 1000-1600 hours at temperature below 70C to break rest. However, some cultivars have low (250 hours) chilling requirement.

Therefore, such areas where temperature in winters fall below 70C for sufficient duration are suited for apple cultivation. Spring frost damages the blossoms of Delicious apples.

So areas experiencing spring frosts should be avoided for apple cultivation. Apple can be grown in a wide range of rainfall from evenly spread rains of 25-37 cm per year to heavy seasonal rains up to 125-175 cm during monsoons.

Soil

Apples grow best on a well-drained, loam soils having a depth of 45 cm and a pH range of pH 5.5-6.5. The soil should be free from hard substrata and water-logged conditions. Soils with heavy clay or compact subsoil are to be avoided.

Cultivars

Scab resistant varieties

Prima, Priscilla, Sir Prize, Jonafree, Florina, Macfree, Nova Easy Grow, Coop 12, Coop 13 (Redfree), Nova Mac, Liberty, Freedom, Firdous, Shireen.

However, Firdous and Shireen have been released as scab resistant varieties for cultivation in J&K.   

Hybrids

Lal Ambri (Red Delicious x Ambri), Sunehari (Ambri x Golden Delicious), Chaubattia Princess, Chaubattia Anupam (Early Shanburry x Red Delicious), Ambred (Red Delicious x Ambri), Ambrich (Richared x Ambri), Ambroyal (Starking Delicious x Ambri).

In J&K, two hybrids namely Lal Ambri (Red Delicious x Ambri) and Sunehri (Ambri x Golden Delicious) have been released though they are not being used commercially.

Pollinizing varieties

The most suitable pollinizing cultivars are: Red Gold, Golden Delicious, Tydeman’s Early Worcester, McIntosh, Lord Lambourne, Winter Banana, Granny Smith, Starkspur Golden and Golden Spur.

Low Chilling varieties

Michal, Schlomit, Anna, Tamma, Vered, Neomi, Tropical Beauty, Parlin’s Beauty

Varieties recommended for J&K; H.P and Uttarakhand

  1. Jammu and Kashmir : Golden Delicious (Late Season), Lal Ambri, Mollies Delicious, Starkrimson, Red June, Irish Peach, Benoni and Tydeman’s Early
  2. Himachal Pradesh : Golden Delicious (Late Season), Red Delicious (Mid season), McIntosh
  3. Uttarakhand, Uttar Pradesh : McIntosh, Chaubattia Anupam

Propagation and Root Stocks

Seedling rootstocks

The apple plantations are raised on seedling rootstocks. The seeds of commercial varieties from fruit juice canning units are used by nurserymen for raising rootstocks. Apple seeds need stratification in moist sand at 40-70C for 60-90 days.

The water soaked seeds are placed between 2 and 3 cm thick layers of moist sand in wooden boxes or polythene bags during December. The stratification can be accomplished in the lower chamber of the refrigerator.

The stratification requirement is also met with, in areas having very cool winters, by direct sowing of seeds in nursery beds in November-December.

The pre-stratified seeds, as indicated by whitish tip at the micropylar end, are sown during February-March on raised beds. One-year-old seedling stocks are ready for grafting during February-March.

Clonal rootstocks

The size controlling clonal rootstocks of apple suitable for Indian conditions are listed below:

CategoryRootstockCharacteristics
DwarfingM 9Short juvenile phase, weak anchorage, suitable for high density planting in flat and irrigated areas only.
Semi-dwarfingM 4, M 7 andSuitable for high density planting and well drained soils; resistant to wooly apple aphid but susceptible to collar rot.
Semi-vigorousMM 111Tree size is 70% of the standard, drought tolerant and resistant to wooly apple aphid

Clonal rootstocks of apple are propagated through mound layering. The rooted layers of the clone are planted in stool beds during winter at a distance of 30 cm in row and 60 cm apart rows. The 3-4 years old layers give rise to numerous suckers during spring. The suckers are ringed or notched near the base during the rainy season and covered with soil to encourage rooting. The difficult to root rootstocks like M 9 are treated with 1000-2000 ppm IBA at the notched/ringed portion for quick root initiation. The rooted layers are separated at the onset of dormancy (December) and lined out in nursery beds for further grafting with scion varieties during February-March. The rootstock should be healthy and disease free and should attain the thickness of 0.9-1.25 cm at grafting height.

Time of grafting / budding

 Tongue grafting          :           February-March

 T-budding                   :           June – July

 Chip budding              :           August

Precautions for budding/grafting

  • The scion should be collected from the mother plants of known pedigree.
  • It should be collected from bearing trees only, during dormancy.
  • One year old shoot growth is ideal for scion wood.
  • Scion sticks should have only vegetative buds and not the reproductive buds.
  • The scion should have 3-5 well developed buds with smooth internodes.

Planting

Before planting an apple orchard, proper decisions should be made on selection of varieties, rootstocks, tree size, spacing, placement of pollinizers and planting layout. In flat and valley areas the planting is done in square or hexagonal system of layout. However, on slopes, contour or terrace planting is preferred.

Time: An early planting of apple in December-January is desirable. However, in areas experiencing late winter snowfall planting can be delayed upto end of February. While planting, graft union should be kept 25 cm above the ground level to avoid colar rot and scion rooting.

Spacing:Spacing depends upon climate, soil type, fertility, rootstock used, availability of moisture and vigour of the cultivar. Training system and length of growing season also determine the planting distance. Usually planting distance of 6.5 – 7.5 m is adequate for standard cultivars.

High Density Planting

The traditional systems of planting have long juvenile period, are labour intensive and low yielding with poor quality fruits. Whereas high density is easily manageable, has higher yield potential, with better quality fruits and higher returns/unit area. But it cannot be adopted in steep, unfertile, shallow & drought prone places. 

There are 4 categories of high density planting which are:

Low (less than 250 plants/ha) 

Moderate (250-500 plants/ha) 

High (500-1250 plants/ha) 

Ultra high density (more than 1250 plants/ha) 

  • With the increase in planting density, the yield may increase, but beyond a threshold density, quality is deteriorated & may not be profitable in terms of economical returns. 
  • The trees should have maximum number of fruiting branches & minimum number of structural branches. 

Tree size control: A key to successful high density planting depends upon control over tree size. Following methods can be adopted: 

  • Use of size controlling rootstocks 
  • Use of spur type scions 
  • Training & pruning methods to induce dwarfing and spreading habits of tree 
  • Mechanical devices like branch bending to control size 
  • Use of chemicals 

But the most convenient method of tree size control is the use of size controlling clonal rootstocks. 

Principles of High Density Apple Production

  • High early yields = high tree density 
  • Balance vegetative and fruiting 
  • Excessive vigor- Small yield, Larger fruit, Poor fruit color development
  • Excessive Fruit Load- Large yields, Small apples, Weak trees
  • Grow fruit, not trees!

With the advent of spur type cultivars and vigour controlling rootstocks, this system of planting is becoming popular especially in case of apple. High density orchards are precocious, easily manageable, has higher yield potential, with better quality fruits and higher returns/unit area. The high density planting cannot be adopted in very steep, unfertile, shallow and drought prone areas. The planting distance depends upon nature/vigour of the variety and the rootstock used. The number of plants that can be accommodated under different planting distances is given below:

Nature of VarietyRootstockVigour of the treePlanting distance (m)No of plants per Ha
Non spur typeMM 111MM 106M 9Semi-vigorousSemi-vigorousDwarf6.0 x 6.04.5 x 4.51.5 x 1.52784944444
Spur typeSeedlingMM 111MM109MM 106M 7Semi-vigorousSemi-Dwarf Dwarf5.0 x 5.03.5 x 3.5 3.0 x 3.0 400816 1111

Pollinizer

Since most of the commercial apple cultivars are self-incompatible, they do not set fruit if planted alone or with certain varieties. Therefore, adequate number of pollinizing cultivar(s) should be planted at the time of planting. The pollinizer variety should not be farther away than 2-tree rows.

It is always desirable that more than one pollinizing variety may be selected for planting an orchard with 33% pollinizing trees. It is very convenient to plant one row of pollinizing variety after every two rows of commercial variety.

The Delicious group of varieties are self-incompatible and cross pollinated, whereas most English varieties are self-pollinated and act as suitable pollinizer for Delicious group of varieties in the proportion of 11-33% in main variety plantation depending on the situation of the orchard.

Time and method of planting

  • Planting is usually done in the month of January and February.
  • Pits measuring 60 cm are dug two weeks before planting. The pits are filled with good loamy soil and organic matter. Planting is done in the centre of the pit by scooping the soil and placing the soil ball keeping the roots intact. Loose soil is filled up in the remaining area and lightly pressed to remove air gaps. The seedlings are staked and watered immediately.

Irrigation

  • Apple trees are particularly sensitive to low soil moisture. Water stress during the growing season reduces number and size of fruits, and increases June drop. 
  • Success of apple largely depends on uniform distribution of rain during the year in case of dry spells during the critical periods supplementary irrigation should be provided. 
  • Water stress conditions results in poor fruit set, heavy fruit drop, low production and poor quality. 
  • The most critical periods of water requirement are April- August and peak water requirement is after fruit set. 
  • Normally the orchards are irrigated immediately after manuring in the month of December-January. During the summer periods, the crop is irrigated at an interval of 7-10 days. 
  • After the fruit setting stage the crop is irrigated at weekly intervals. Application of water during the fortnight preceding harvest markedly improves the fruit colour. 
  • Thereafter till the onset of dormancy, irrigation is given at an interval of 3-4 weeks.

Training and Pruning

The plants are trained to establish strong framework of scaffold limbs capable of supporting heavy yield with quality fruits, regulate annual succession of crops, expose maximum leaf surface to the sun, direct the growth of the trees so that various cultural operations like spraying and harvesting become economical, protect the tree from sun burn and promote early production. The training methods differ for standard and dwarf trees.

Training of standard trees

Trees are mostly trained to modified central leader. The central leader is allowed to grow to a height of 2-3 m when its growth is restricted. Modified central leader combines the best qualities of the central leader and open centre systems. A leader develops on young trees until it reaches the height of about 3 m, then its growth is restricted.

One year old apple tree should be pruned to 45-60 cm above the ground immediately after being planted. This level may appear low but it helps to develop low headed trees, which are less likely to tilt on one side with winds and in which the main stem is not affected by sun burn.

The first year dormant pruning

Three primary scaffold branches are selected. These should be spaced about equally around the trunk preferably with a vertical spacing of 10-15 cm between them. The primaries are headed back by about 1/4thto 1/3rdof their length. The leader is also headed back by about 1/4thto 1/2ndof its length so that it is always higher than the primary scaffold limbs. If three well spaced primary scaffold limbs are not obtained in the first year, the available limbs may be headed back to 45 cm from the trunk to suppress their development until a third scaffold can be selected at the end of the second growing season.   

Second year dormant pruning

During second dormant pruning 5-7 secondary branches per tree     usually 2 on each primary scaffold should be selected in the second dormant season besides 1 or 2 primary scaffold on the central leader. Secondary limbs should be left full length and not headed back until it is necessary to maintain balance with the primaries or other secondaries. The central leader should also be headed back as in the first year to stiffen it and to promote the development of lateral shoots. Shoots competing with central leader should be removed. Upright growing shoots should be removed.

Third year dormant pruning

The selection of primaries on the central leader should be continued and likewise secondaries on the lateral scaffold and tertiaries on the secondary limbs. These should be directed partially outward. Pruning of central and lateral leaders should be done as in the previous years to maintain growth. Further, training consists of thinning out on wanted branches and cutting others to desirable side limbs.


Fourth dormant pruning

The selection of primary shoots on the central leader should be continued. The central leader should be pruned to a vigorous lateral shoot at 3 m height. The selection of other lateral shoot should be continued as in the previous years. By this time, training has been largely completed. Now pruning should be done in such a manner as to permit the best development of the crop. The tree should be thinned out. The remaining branches are cut to side limbs as is done in the third dormant pruning. A moderate number of small shoots should be left in the centre of the tree for fruit bearing wood. Adequate thinning out of branches and fruiting wood maintains a well distributed bearing branches and reduce excessive spread and breaking of branches.

By the fifth summer after planting, most of the apple varieties produce enough fruits. 

Pruning

Partial or complete removal of vegetative growth of fruiting wood from a plant to control its size, remove broken or damaged tissues, alter plant shape, remove unnecessary growth or balance fruiting and vegetative growth is termed as pruning. The basic steps of pruning standard bearing trees are:

  • Start pruning at the top of the trees and work downward.
  • Cut upward growing limbs back to strong laterals.
  • Remove the crowding branches and thin out the remaining leaving the vigorous fruiting wood well spaced along the length of limbs.
  • Remove dead, broken and diseased wood.
  • Remove parallel growing shoots causing crowding and shading and opposite growing shoots at a point on the stem.
  • Remove all water sprouts except the occasional ones, which may be needed to fill a vacant space in the canopy.
  • Divert branches to open areas by pruning to desirable laterals.
  • Avoid removing too many branches and so reducing potential fruit yield. The main branches, which have lost the vigour, can be stimulated by pruning.

Precautions in pruning

  • When the limb larger than 3 cm in diameter is removed, the pruning cut should be made as close as possible to the branch from which the limb arises without leaving a stub.
  • Large pruning wounds should be protected with Bordeaux paste or Chaubattia paste to check the entry of rot causing fungi.
  • In 1 or 2 year old shoots, heading back can be done to promote growth of side shoots and quick wound healing. In 3 years old and older shoots, pruning should be shifted to thinning out cuts to reduce vegetative growth and promote fruiting.
  • The competing branches should be thinned out rather than headed back. 

  Manuring and fertilization

The fertilizer dose depends upon the soil fertility, type of soil, kind and age of trees, cultural practices, climate and crop load. The dose of manures and fertilizers should be determined on the basis of soil and leaf analysis. The fertilizer schedule for apple is as under.

Age of tree     Fertilizer dose (g/tree)                                   

    Urea    Di-ammonium phosphate   Murate of potash

  1. 35                               20                                            50
  2. 70                              45                                            100
  3. 105                            65                                            150
  4. 140                            85                                            200
  5. 175                            110                                          250
  6. 245                            150                                          350
  7. 315                            195                                          450
  8. 385                            235                                          530
  9. 455                            280                                          630
  10. 525                            325                                          730
  11. 630                            385                                          900
  12. 735                            450                                          1050
  13. 840                            515                                          1190
  14. 940                            580                                          1345
  15. Onwards 1050              645                                          1500

The application of fertilizers may be supplemented with farm yard manure @ 10 Kg/year age of the tree with the maximum of 100 Kg. In bearing trees, farm yard manure along with phosphorus (P2O5) and potassium (K2O) should be applied during December-January. Nitrogen (N) is applied during February-March, 2-3 weeks before bud break. The N can be given in two split doses, first 2-3 weeks before bud break and second one month after flowering, where the irrigation facilities are available. The fertilizer should be broadcasted in the tree basins 30 cm away from tree trunk to the canopy drip line and mixed well in the soil.

There are deficiencies of macro and micro-nutrients. The symptoms and corrective measures of important nutrient deficiencies are as under.

NutrientDeficiency symptomsDose of ChemicalTime of foliar application
NitrogenRestricted shoot growth, leaves remain normal in shape, pale yellow in colour. Older leaves are first affected. Fruits remain smallTwo sprays of 0.5% ureaAfter petal fall and one month later
Boron Fruits become misshapen by hardy corky tissue. Fruit cracking may also occur. Leaves are dark green, thick and brittle starting at the tip.Two spraysof 0.1% boricacidPre-bloom andpost bloom
Zinc Bark along shoot fail to develop, leaves remain small and narrow. Older leaves may fall in severe case. Fruits remain small and misshapen.0.5% zinc sulphateAfter petal fall
Manganese Early defoliation occurs on the top of the trees. Chlorosis between main veins starting near the margin of leaves and extending towards mid rib. Fruits develop poor colouration0.4% MnSO4After petal fall
CalciumMargins of older leaves become necrotic and shatter. Bitter pit symptoms also appear near calyx end of fruits0.5% CaCl230-45 days before harvesting

Harvesting and post harvest management

Apple fruits continue their metabolic processes even after harvesting. The maturity of fruits do not coincide with ripening. The fruits usually do not attain fully ripe edible quality on the tree while harvesting. The fruits should be harvested at proper picking maturity to proper edible quality at ripening. There are several maturity indices which can be followed in proper fruit harvesting. The TSS (Total Soluble Solids) of fruit pulp, ease in separation of fruit from spur, change in ground surface colour from green to pale, change in seed colour to light brown, fruit firmness and days from full bloom to harvest are some reliable maturity indices for apple which can be considered singly or in combination. Apple fruits should be picked in such a way that bruising and stem punctures are avoided and pedicel must remain with fruit. Apple should be grasped between index finger, middle finger and thumb, and quick upward twist will easily pluck the fruit along with pedicel. Fruit should be harvested during cooler hours, preferably in the morning.

Pre-cooling

After picking, the fruit should be placed in cool and ventilated place to remove field heat before packing. Before grading and packing, fruit should be properly washed and dried.

Grading

On the basis of appearance and quality apple is graded viz., AAA, AA and A; A, B, and C; or extra fancy, fancy class I and fancy class II. On the basis of size the fruits are graded into following classes. 

GradeMinimum fruit diameter (± 2.5 mm)Approx. Measurement with thumb and finger
Super largeExtra largeLargeMediumSmallExtra smallPittoo (including culls)858075706560554 fingers and thumb4 fingers and some space3-4 fingers2-3 fingers1-2 fingersfingerNo space

Packaging

Apples are packed in wooden boxes. Each box usually carry about 10 Kg or 20 Kg fruits. The fruits are packed by lining the inside of box with newspaper, sheets and keeping margins for the overhanging flaps. The wrapped fruits are initially padded with wood wool/pine needles at the bottom of box and later in between well arranged intervening layers. The top layer of fruits is covered with paper by bringing together the overhanging flaps followed by nailing. The box is further reinforced eternally by clamping with a tight 14-16 gauge steel wire for distant markets. For packing wrapped boxes, the arrangement of different grades of apples is given below.

GradeBox size inner dimensions (cm)Size of wrapping paper (cm)Number of fruits/boxNumber of  layers
Super largeExtra largeLargeMediumSmallExtra smallPittoo45.7 x 30.5 x 27.945.7 x 30.5 x 25.445.7 x 30.5 x 30.545.7 x 30.5 x 27.945.7 x 30.5 x 25.445.7 x 30.5 x 25.4-27.9 x 27.926.7 x 26.725.4 x 25.424.1 x 24.122.8 x 22.821.5 x 21.5Not wrapped54.5760.6396112128-132160Variable334445Loose

Besides wooden boxes, corrugated fibre board (CFB) cartons offer a variable substitute. The usual dimensions of CFB cartons with trays are 50.4 cm x 30.3 cm x 28.2 cm (outer jacket) and 50.0 x 30.0 x 28.2 cm (inner case).

Storage

Shelf life of apple can be prolonged by providing optimal storage conditions. The recommended storage temperature for apple is -1.10C to 00C which is about 0.8 – 1.80C above the average freezing point of most apple varieties. The relative humidity of 85-90% should be maintained in the cold storage. Most apple varieties can be stored for 4-8 months after harvesting. Ambri has the longest storage life.

Insect-Pests 

1.Sanjose scale

It is a polyphagous pest; small, grey or brownish grey specks with a central nipple, twigs and fruits often surrounded by reddish or pinkish rings. Severely infested tree bark is covered with grey layers of overlapping scales, appearing as if sprayed with ash. Underneath the grey dots are lemon yellow coloured soft bodied insectsIt causes damage by sucking sap from the stems, branches, leaves and even fruits. If the infestation is allowed to develop unchecked, it results in the death of the tree. Infested fruits fetch poor price in the market. Sanjose scale can be controlled by spray of 2% miscible tree spray oil (4 L Hindustan Petroleum Tree Spray Oil (HPTSO)/SAVO-OEH/Ankur) from end of February or in between late dormancy and green tip stage. Spray with chlorpyriphos (0.02%), dimethoate (0.03%) or phosphamidon (0.03%) to kill crawlers and newly settled scale insects in May.

2.Woolly apple aphid

Small, brown and greyish purple sucking aphid which attacks bark and roots forming a white waxy material, resembling little tufts of wool. Active from April-December but found in large numbers on aerial parts after rains (late August-October). Aphids suck sap from branches, twigs and roots. Galls are formed at the point where aphids feed. In non-bearing trees and nurseries place granules of phorate (10-30 g thimet 10G) or carbofuran (30-50 g Furadan 3G) at 5 cm depth in the root zone of 1-4 years old trees. However, in bearing trees, in addition to dormant sprays for sanjose scale , application of methyl dematon 25 EC (0.025%), dimethoate 30 EC (0.03%), malathion 50 EC (0.05%) between petal fall and June. Serious infestation near the harvest can be controlled by using dichlorvos 76 EC (0.05%). Use resistant rootstock of MM series and M 25.

3.Stem borer

Beetles damage the stem, and branches by drilling holes. Saw dust along with pallets can be seen hanging out from these holes. Clean the holes with flexible wire and then insert 0.5 g paradichlorobenzene (PDCB) and plug the holes with mud or insert cotton wick soaked in petrol or dichlorovos (0.15%). All badly infested trees or dying wood should be cut and burnt before leaf drop.

4.European red mite

Damage apple foliage by feeding on green matter and sap, causing loss of chlorophyll, bronzing followed by leaf drop and weakening of buds. Feeding results in poor fruit size and quality of fruits get deteriorated. Excessive feeding results in fruit drop during the season, reduced blossom and fruit set in the subsequent years. Spray dicofol (0.05%) or wettable sulphur (0.25%) at pink bud stage and later when the mite population exceeds 15-20/leaf.

Diseases

1.Apple scab

The disease affects both leaves and fruits. Symptoms usually appear first on the under surface of leaves of fruit spurs, the side exposed when the fruit buds open in the spring. Once the entire leaf has unfolded, both the sides may be infected. Velvety brown to olive green powdery lesions (spots) which turn mousy black with age, appear on the leaves. At first the margins of the lesions may cover a large portion of leaf, a condition known as sheet scab, and may lead to premature yellowing of leaves, defoliation and fruit drop. Young infected fruits develop dull, brownish black round spots with a serrate outline. Severe early infection results in the formation of mis-shapened cracked, knotty fruits which allow the entry of other organisms causing fruit rot. For reducing primary inoculum of the fungus, spray 5% urea shortly before general leaf fall to hasten the leaf decomposition. Collect and burn fallen leaves during winter. Following protective spray schedule may be followed:

  • At silver tip to green tip stage spray Mancozeb (0.3%) or Dodine (0.1%) or Captan (0.3%).
  • At pink bud stage, spray Fenarimol (0.04%) or Bitertanol (0.05%) or Mancozeb (0.3%) + sulphur (0.2%).
  • At petal fall stage, spray Carbendazim or Thiophanate methyl (0.05%).
  • At (pea sized) fruit (mid May-mid June) spray Dodine (0.075%) or Fenarimol (0.04%) or Mancozeb (0.3%) or Bitertanol (0.05%).
  • At (walnut sized) fruits (15-21 days after 4thspray) Carbendazim or Thiophanate methyl (0.025%) + Mancozeb (0.25%) or Captan (0.3%).
  • At fruit development (40 days before harvest), spray Captan (0.3%) or Bitertanol (0.05%) or Mancozeb (0.3%) or Penarimol (0.04%).
  • Spray Mancozeb (0.3%) or Captan (0.3%) 20-25 days before harvesting.

2.Powdery Mildew

Small, greyish or white powdery patches appear on young leaves. The infected leaves crinkle and curl up. The greyish white powdery coating covers the entire leaf. Infected foliage becomes hard and brittle. The powdery mass on twigs disappears and brown felt like covering with dark brown fruiting bodies are seen. The diseased twigs are stunted or get killed and dry up. Affected floral parts shrivel and are blighted. Young infected fruits show russeting. Prune infected dormant shoots, tips and silvered areas to avoid infection in the next season. Spraying the trees at green tip, petal fall, 20 and 40 days after fruitlet stage with Dinocap (50g/100 L water) or Carbendazim (50g/100 L water) or Tridemorph (50g/100 L water).

3.Sooty blotch and flyspeck

Both the diseases appear as sooty blemishes on the external surface of fruits especially under high humidity during rainy season. It lowers the market value of fruits. To control this disease give one spray 40 days before harvest and other spray 15-20 days before harvest with captafol (200 g/ 100 L water) or Carbendazim (50g/100 L water) or Mancozeb (200 g/ 100 L water). Dip the harvested fruit for 1 minute in stable bleaching powder ((5 Kg/ 100 L water) or Sodium chlorate (3 Kg/ 100 L water) before packing.

4.Collar rot

The disease appears mostly near the graft union or on the lower trunk or at pruning wounds. The bark of the diseased tree at soil level becomes cankered, soft and spongy. The necrotic tissue turns dark brown and wood beneath the bark is stained dark brown. Bark above ground dries out and splits from the wood. Leaves become purple red in the late summer and fall. The affected tree shows little or no shoot growth and girdling leads to death of the tree. For the control of collar rot, clean the infected collar area with sharp knife and apply Bordeaux paste or Chaubatia paste. Raise the bud/graft union height to 40-70 cm from soil level. Pre-plant dipping of seedlings in fungicides like Difoltan ((200 g/ 100 L water) or Copper oxychloride (300 g/ 100 L water). Adopt cultural practices like removal of crop residue and fallen fruits, avoid injury to stem, removal of weeds from the tree basins.

5.White root rot

Affected trees show bronzing and yellowing leaves, sparse foliage and retarded growth. Roots turn brown and remain covered with white cottony mycelia mat of the fungus in rainy season. The tree ultimately die. Maintain proper drainage in orchard. Unearth and remove infected roots of trees during dormancy. Apply chaubatia paste (red lead, copper carbonate and linseed oil; 1:1:250) on cut ends and healthy portions of roots. For curing the ailing trees, give at least 3 drenching of Carbendazim (0.1%) or Aureofungin (0.05%) at an interval of 15-20 days during monsoon. Application be made in 15-25 cm deep holes, 30 cm apart throughout the drip area of the tree.

By: Dr. Parshant Bakshi

If you like this article, spread with love and share it with your friends. Also, You can support our initiatives by adopting a plant here