KERALA AGRICULTURAL UNIVERSITY

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GUIDELINES FOR MAXIMIZING FERTILIZER USE EFFICIENCY

 

Choice of a fertilizer depends on unit cost of nutrient present in it and its agronomic efficiency under a given situation. Fertilizer is a valuable input and measures should be taken to reduce its losses and to increase its uptake and utilisation by the crop. Selecting a situation-specific fertilizer and choosing the time and method of application according to crop demand would minimize losses and increase its efficiency.


Nitrogenous fertilizers

Most crop plants recover only 25-35 per cent of the nitrogen applied as fertilizers. Losses occur by ammonia volatilisation, denitrification, immobilization to organic forms, leaching and run off. Utmost care should be bestowed in selecting the type of fertilizer as well as the timing and method of application.

 

Choice of the nitrogen fertilizer

1. In submerged rice soil, ammoniacal and ammonia producing fertilizers like urea are most suitable since ammonia is the most stable form of nitrogen under such conditions.

 

2. For acidic upland soils, ammoniacal fertilizers are most suitable during rainy season since ammonium is adsorbed on soil particles and hence leaching losses are reduced. Adsorbed ammonium is gradually released for nitrification and thus becomes available to crops for a longer period.


3. In highly acidic upland soils, urea is preferred to ammonium sulphate as the former is less acid forming.

 

4. In alkaline upland soils of low rainfall regions, nitrate fertilizers are preferred to ammoniacal fertilizers or urea since ammonia may be lost by volatilization under alkaline conditions.
 

Management of nitrogenous fertilizers
1. Almost all the nitrogenous fertilizers are highly amenable to losses and since most of the crops require nitrogen during the entire growth period, split application is necessary to ensure maximum utilization by crops.


2. More number of splits may be given for long duration crops as well as perennial crops.


3. Nitrogen losses from fertilizers are more in coarse textured soils with low cation exchange capacity (CEC) than in fine textured soils. Hence more number of splits is necessary to reduce loss of fertilizer nitrogen from sandy and other light soils.

 

4. For medium duration rice varieties, nitrogenous fertilizers should be given in three splits, as basal, at maximum tillering and at panicle initiation stage.

 

5. In coarse textured sandy or loamy soils, the entire dose of nitrogenous fertilizers may be applied in 3-4 splits at different stages of growth of rice crop.

 

6. In areas where split application of nitrogen is not feasible due to water stagnation after planting/sowing, full dose of nitrogen as basal may be given in the form of neem coated or coal tar coated urea.

 

7. In double cropped wetlands, 50 per cent of N requirement of the first crop may be applied in the organic form.

 

8. As far as possible, liming should be done one or two weeks prior to the application of ammoniacal or ammonia forming fertilizer like urea since ammonia is likely to be lost by volatilization if applied along with lime.


9. Almost 70 per cent of N in urea applied by broadcast to flooded soil is lost by volatilization, immobilization and by denitrification

 

Measures to reduce the loss of N from applied urea
1. Urea super granules or urea briquettes may be used in places where soil is clayey and has cation exchange capacity more than 10 cmol (+) per kg of soil.


2. Sulphur or lac coated urea is suitable where soil is liable to intermittent flooding and in situations where water management is difficult. This is more suitable for direct sown crop.


3. Urea may be mixed with moist soil and kept for 24-48 hours before application to the field. Alternatively, urea may be mixed with moist soil, made into balls of about three inch diameter and dried under shade. The balls may be placed deep into subsoil.

 

4. Mixing urea with one fifth its weight of neem cake (5:1) prolongs the period of nitrogen availability to the crop.

 

5. For submerged soils, coating urea with coal tar and kerosene (100 kg urea is mixed with 2 kg coal tar dissolved in one litre kerosene) before mixing with neem cake is preferred to simple mixing with neem cake.


6. Coating urea with neem extract (containing about 5 per cent neem triterpenes) at 1 per cent rate and shade drying for 1 to 1.5 hours before applying in direct seeded puddled lowland rice increases nitrogen use efficiency.

 

7. As far as possible, urea may be applied by deep placement or plough sole placement. Deep placement of prilled urea or super granules during the last ploughing followed by flooding and planting is beneficial in light soils. Urea briquettes or super granules may be placed between four hills of transplanted rice, whereas sulphur coated or lac coated urea may be broadcast on the surface.

 

8. Foliar spray of 5 per cent urea solution can be practised in situations where quick response to applied nitrogen is required. If power sprayers are used, the concentration may be increased to 15 per cent. Fresh urea should be used to avoid toxicity due to biuret.


Phosphatic fertilizers

Fertilizer phosphorus is an expensive input and its management poses serious problems due to several complexities in its behaviour in different types of soil. This often results in its poor recovery from applied fertilizers.


Choice of phosphatic fertilizer
1. In slightly acid, neutral or mildly alkaline soils, water soluble phosphatic fertilizers are more suitable.

 

2. In wetland rice soils, water soluble phosphatic fertilizers are preferable as pH of most of the submerged soils is near neutral.


3. In strongly acidic soils whose pH does not rise above 5.5 to 6.0 even on submergence, phosphatic fertilizers containing citrate soluble form of P like basic slag, dicalcium phosphate, steamed bone meal etc. are suitable.


4. For highly acidic upland soils or submerged soils whose pH will not rise above 5.5 even on submergence, powdered rock phosphate is suitable. Soil acidity converts tricalcium phosphate in rock phosphate to plant available monocalcium form.

 

5. For short duration crops where quick response is required, water soluble phosphatic fertilizers are most suitable.


6. For perennial crops like rubber, oil palm, coffee, tea, cardamom etc. phosphorus in the form of rock phosphate can be applied.


7. In black soil (Chittur taluk of Palakkad District) phosphatic fertilizers containing water soluble phosphate like single superphosphate are most suitable.


Management of phosphatic fertilizers
1. Acid soils have to be amended with lime, dolomite or magnesium silicate and alkali soils with iron pyrite or sulphur before application of phosphatic fertili-zers. This will help to reduce fixation and increase availability of P.


2. Surface application or broadcasting is preferred for shallow rooted crops whereas placement in the root zone is advantageous in deep rooted crops.


3. Rock phosphates can be used advantageously in rice, grown in acid soils during the virippu season. Powdered rock phosphate may be applied and mixed thoroughly with soil by ploughing. After two or three weeks, the field may be flooded, worked up and planted with rice. Under this situation, phosphorus in rock phosphate gets converted to iron phosphate, which on subsequent waterlogging becomes available to the rice crop.

 

4. Rock phosphate can be used successfully as a phosphatic source for leguminous crop since its root system can extract phosphorous from rock phosphate.


5. In single crop wetlands where rice is grown in the virippu season, application of phosphatic fertilizers can be dispensed with for the rice crop, if the second crop (usually legume or green manure) is given phosphatic fertilizers.


6. In case of rice-legume cropping sequence in acid soils, application of rock phosphate to the pulse crop helps to skip phosphatic fertilizers in the succeeding rice crop.

 

7. Since phosphorus requirement of seasonal crops is confined to the early stages, phosphatic fertilizers are to be applied at the time of seeding or planting. Top dressing of phosphatic fertilizer leads to wastage of the fertilizer nutrient. Further, excessive phosphates may lead to deficiency of micronutrients such as zinc, boron etc.

 

8. Under adverse soil conditions and where quick result is required, spraying water-soluble phosphatic fertilizers like triple superphosphate or hot water extract of superphosphate can be resorted to.

 

Potassium fertilizers
For most crops, potassium can be supplied as muriate of potash. But in crops like tobacco and potato, muriate of potash may cause chloride injury, reducing quality of the produce. In such cases, K may be applied as potassium sulphate.


Management of potassium fertilizers

1. In coarse textured soils and in heavy rainfall regions, potassium fertilizers should be applied in as many splits as possible, to reduce loss of potassium.


2. In fine textured soils, the entire dose of potassium fertilizers may be applied as basal.

 

3. In acid soils, potassium fertilizers should be applied only after lime application to prevent loss of potassium by leaching.

 

Lime

Acid soils are characterised by high saturation of the exchange complex with hydrogen and aluminium. Crops grown in such soils suffer due to unavailability of most plant nutrients, especially calcium. Application of liming materials increases the availability of nutrients and alleviates Ca deficiency.

 

Liming materials
Burnt lime [CaO], slaked lime [Ca (OH)2], powdered limestone [CaCO3] and dolomite [CaMg (CO3)2] are some of the materials used as sources of calcium.


Management

1. In acidic submerged soils, flooding brings about rise in soil pH and hence response to lime is less marked.

 

2. Legumes are benefitted most by liming.

 

3. For better results, liming materials should be incorporated into the soil.


4. For seasonal crops and in situations where immediate results are required, burnt lime or slaked lime may be used. For perennial crops, powdered lime stone or dolomite is sufficient.

 

5. Extreme care should be taken while broadcasting burnt lime and slaked lime as they can cause scorching of leaves.

 

6. In case of wetland rice, drain the field prior to lime application and reflood after 24 hours. Flushing the soil by sequential flooding and draining will help to wash out the displaced acid from the soil. 7. In extreme case of calcium deficiency, 1 per cent solution of calcium chloride may be applied by foliar spraying.

 
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BEEKEEPING (APICULTURE)

 

True honey bees belong to the family Apidae and genus Apis. They are social insects living in colonies. A colony consists of a queen, several thousand workers and a few hundred drones. There is division of labour and specialization in the performance of various functions. They build nests (combs) with wax secreted from the wax glands of worker bees. The bees use these cells to rear their brood and store food. Honey is stored in the upper part of the comb; beneath it are rows of pollen storage cells, worker brood cells and drone brood cells in that order. Some Apis species build single comb in open, while others build multiple combs in dark cavities.

 

Species of honeybees
There are four species of honeybees in India. They are:

 

Rock bee (Apis dorsata): They are giant bees found all over India in sub-mountainous regions up to an altitude of 2700 m. They build single comb nests with an area up to 1 m2 or more. They are good honey gatherers with an average yield of 50-80 kg per colony.

 

Little bee (Apis florea): They are the smallest of the true honeybees found in plains of India up to the altitude of 500 m. They build single vertical combs. They are poor honey yielders and yield about 200-900 g of honey per colony.

 

Indian bee (Apis cerana indica): They are the domesticated species, which construct multiple parallel combs with an average honey yield of 6-8 kg per colony per year.

 

European bee/Italian bee (Apis mellifera): They are also similar in habits to Indian bees and build parallel combs. They are bigger than all other honeybees except Apis dorsata. The average production per colony is 25-40 kg.


Stingless bee (Trigona iridipennis): In addition to the above, another species is also present in Kerala known as stingless bees. They are not truly stingless, but the sting is poorly developed. They make nests in the ground, hollows of trees, bamboo, rocks or cracks of walls. Honey and brood cells are separate in the nest. They are efficient pollinators. They yield 300-400 g of honey per year.


Swarming

Swarming is the natural instinct of honeybees to reproduce its colonies. By swarming, strong colonies are divided naturally. It occurs mostly when the colony population is at its peak. Some of the several reasons for swarming are sudden honey flow, sudden failure of queen to lay eggs, congestion in the colony, want of breeding space, bad ventilation etc. Dividing the colonies or keeping young queen or preventing over crowding of bees or adding new combs can prevent swarming.


Absconding

Absconding is the total desertion of colony from its nest due to incidence of disease / pest attack, too much interference by human beings or robbing of honey by bees from other colonies. Proper hive management can prevent it.

 

Communication
The worker bees communicate with other bees about the exact location of nectar, pollen, water, next nesting site etc. by means of dances. Round dance is performed when the food is located within 100 m from hive and wagtail dance to communicate the location of food source when it is more than 100 m away from the hive.

 

Bee space

It is the space large enough to permit the free passage for worker bees but too small to encourage bees building a comb and too large for bees to deposit propolis in it.

 

Indian bee (Apis cerana indica)

This is the domesticated hive bee in Kerala. A colony consists of a queen, 20,000 to 30,000 workers and a few drones. This species has gentle temperament and responds to smoking. Lack of flora leads to absconding by bees. It also has a strong tendency for swarming. It yields 8-10 kg of honey per colony per year.

 

Bee-box
ISI Type-A box is recommended for the State of Kerala. A division board may be added to the bee box for adjusting the internal space depending on the strength of the colony. It can be procured from beekeepers. Wild feral colonies can be hived. Beekeepers in different regions use local hives made of low cost wood. The wood should not have a strong smell. Kail (Pinus excelsa), teak (Tectona grandis), toon (Toona ciliata) anjili (Artocarpus hirsutus), punna (Calophyllum inophyllum) etc., are some of the suitable woods. The hives should be preferably painted white on outside to protect the timber from weathering.

 

Hiving wild colony

It is done during evening hours. Smoke the colony slightly, cut out the combs one by one and tie to the brood frames with plantain fibre. Arrange them in the box.


Location of beehives

The apiary must be located in well-drained open area, preferably near orchards, with profuse source of nectar, pollen and water. Windbreaks may be provided by planting shrubs, flowering plants and also creepers like antigonon. Shade must also be provided. Ant wells are fixed around the hive stand. The colonies must be directed towards east, with slight changes in the directions of the bee box as a protection from rain and sun. Keep the colonies away from the reach of cattle, other animal, busy roads and streetlights.

 

Management of colonies
Inspect the beehives at least once in a week during brood rearing / honey-flow seasons preferably during the morning hours. Bright, warm and calm days are suitable. If sunlight falls directly on the beehive spread cloth or a towel over the same. Look for freshly laid eggs to ensure that the colonies are healthy. Clean the hive in the following sequence, the roof, super/supers, brood chambers and floorboard. Observe the colonies regularly for the presence of healthy queen, brood development, storage of honey and pollen, presence of queen cells, bee strength and growth of drones. Look for the infestation by any of the following bee enemies.

 

Wax moth (Galleria mellonella): Remove all the larvae and silken webbings from the combs, corners and crevices of bee box.


Wax beetles (Platybolium sp.): Collect and destroy the adult beetles.


Mites: Clean the frame and floorboard with cotton swabs moistened with freshly made potassium permanganate solution. Repeat until no mites are seen on the floorboard.


Diseases: The dead larvae due to Thai sac brood virus (TSBV) in the comb cells may be removed and destroyed.

 

Management during lean season

Remove the supers and arrange the available healthy broods compactly in the brood chamber. Provide division board, if necessary. Destroy queen cells and drone cells, if noted. Provide sugar syrup (1:1) @ 200 g sugar per colony per week for Indian bees. Feed all the colonies in the apiary at the same time to avoid robbing.

 

Management during honey flow season

Keep the colony in sufficient strength before honey-flow season. Congestion in the hive must be avoided and surplus honeybees are drawn to supers. Provide maximum space between the first super and the brood chamber and not above the first super. Place queen excluder sheets in between brood and super chamber to confine the queen to brood chamber. Examine the colony once in a week and frames full of honey should be removed to the sides of the super and such frames can be raised from brood to super chamber. The frames, which are three-fourth filled with honey or pollen and one-fourth with sealed brood should be taken out of brood chamber and in its place empty combs or frames with foundation is added. The frame with comb foundation should be placed next to the brood nest. The combs, which are completely sealed, or two-third capped may be taken out for extraction of honey and returned to supers after honey extraction. This helps the colonies to activate the bees to collect and store more honey. Two or three such extractions are possible during a surplus flow. Extraction of uncapped honey will result in fermentation. Honey extraction, after the flow is over, should be avoided to save the bee colonies from robbing. Care should be taken to retain sufficient combs with honey in the brood chamber or reduce the lean period.

 

Migratory bee keeping

The moving of bee colonies from one place to another to capture increased nectar flow of a particular flora is called migratory beekeeping. Copious flow of extra floral nectar available on rubber trees during January-April is exploited by shifting bee colonies to these plantations during this period.

 

Similar practice is done in cashew plantations and in other orchards too. Maintaining bee colonies in orchards will increase the yield, since pollination is more efficient in such orchards.

 

Shifting of colonies is done after sun set. Colonies should be prepared as follows. Extract available honey and fasten all the weak combs to frames with plantain fibres. Secure the frames to the chamber with packing. Close the bee entrance with cotton. Then secure the bee-box (floorboard, brood chamber, supers and roof) firmly with strong threads. Do not tilt or topple beehives while stacking them in the conveyance or during transit. Avoid strong jerks and shocks while transporting.

 

Set up the beehives as described above at the new site. Inspect the condition of combs and tighten loose threads, if any. This inspection should be done only in dim light. Next morning remove the cotton plug at bee entrance. Later provide comb foundation sheets, if necessary and provide sufficient space for storage of honey.


Extraction of honey

Honey is extracted only from super combs using honey extractor. The sealing of cells on combs is removed with sharp knife before placing in the extractor. Extractor should be worked slowly at the beginning and at about 150 rpm at the end for about 1 to 2 minutes. Then the sides of the frames are reversed and the extractor is again worked. Extracted honey is filtered through muslin cloth. Providing a bee escape between the brood and super on the day prior to honey extraction keeps the bees away from the super. Remove the escape soon after honey extraction.

 

Processing of honey
Heat the honey to 45ºC by keeping it in a water bath. Sieve it to remove wax particles, debris, dust and pollen. Again heat it to a temperature of 65ºC in water bath and maintain it for 10 minutes. Then cool and filter it in 80-mesh muslin and store in glass, porcelain, earthenware, enamelware or stainless steel containers. Bulk storing can be made in mild steel containers lined with bee wax.

 

Italian bee (Apis mellifera)

It is a native of Europe introduced to Himachal Pradesh and Punjab during 1962-64 and introduced to Kerala on a trial basis from Haryana in November 1992. It maintains a prolific queen, swarms less, has gentle temperament and is a good honey-gatherer. It is known to be resistant to TSBV. A healthy colony may contain 60,000 to 80,000 worker bees. The following modifications are to be followed in beekeeping with Italian bees.

 

Bee-box

Langstroth beehive with ten frames each in brood and super chambers and a division brood chamber is recommended. The brood and super chambers are of the same size.

 

Procuring bee colonies

Colonies can be obtained either by dividing existing colonies or by buying from other agencies.

 

Location of beehives

Follow the practices as in Indian bees, but use a strong four-legged stand well protected from ants and other crawling insects by providing ant wells.


Management of colonies
Apart from the management practices followed for Indian bee, the practices as mentioned below may be followed.

 

Sources of pure water should be available near the apiary. Stagnant water or water in a container is not appropriate because it can spread nosema disease. Flowing water near the apiary should serve as a good source. As an alternative, water trickling from a container set on a stand and falling on a slanting wooden plank can be provided.

 

During the brood rearing season (growth period) from October to January, replacement of old queens by young healthy ones, uniting the weak colonies and giving supplementary feeding as and when required should be done. Colonies should be provided with enough space for brood rearing and food storage, by giving comb foundation sheets one at a time.


In areas where queen mating is a problem, especially when only a few colonies are kept in isolated pockets, the colony with virgin queen is to be transferred to areas where more number of colonies are kept so as to ensure the availability of queen in sufficient numbers and afterwards returned to the former apiary.

 

During honey flow season (January-April), provide raised combs in the super and the number of combs to be added depends on the strength of the colony. Only ripe honey is harvested when two-third of the comb cells are capped so that honey contains less than 20 per cent moisture. Care should be taken to see that the bee colonies are not stripped of all the honey stores. Enough stores of honey should be ensured in the hive at the end of honey flow for use during the following lean period. For migratory bee keeping, follow the practices as adopted for Indian bees.

 

Extraction of honey
The sealing of comb is removed with a sharp knife and the extraction done in an extractor designed for langstroth size frames. Extracted honey is filtered through a coarse cloth to remove the impurities.

 

Processing of honey

To be done as described under Indian bees. During the lean season (May-September), remove the super chambers, arrange the available healthy brood combs in the brood chamber and use division boards to restrict the space. Provide artificial feeding once in a week by way of 1:1 sugar syrup in water. Each colony may require syrup prepared from 500-750 g sugar a week depending on the size of the colony and availability of stored food. When there is dearth of natural source, pollen substitutes may be provided in the colony.

 

Pests and diseases
Brood mite (Tropilaelaps clareae): Infests the brood and the infestation is severe during the major brood rearing season (October-January). These ectoparasites feed on the haemolymph of developing broods slowly killing them. Dusting sulphur on the topbars of the frames @ 200 mg/ frame at 7-14 days interval during brood rearing season is very effective in checking the infestation.

 

Yellow-banded wasp (Vespa cincta): These predatory wasps catch the bees from both the hive entrance and inside the hives. Locating and destroying their nests by burning or insecticidal usage is an effective control measure.


Wax moth (Galleria mellonella): Infests weak and unattended colonies. Proper cleaning of the hives periodically and keeping the hives without cracks and crevices can avoid infestation.

 

Black ants: Various species of black ants intrude beehives and take away honey and pollen and kill the brood and bees, which may lead to absconding of colony. The apiary should be kept clean and the ant nests destroyed by insecticidal applications. Ant wells should be provided for the beehive stands.

 

Red tree-ant (Oecophyla smaragdina)

If not protected properly, the red tree-ants can cause considerable damage to the bees and the brood. The bees that come in contact with the ground are attacked and killed by the ants and dragged to their nests by a number of ants. In the apiary, if the branch of a tree with these ants happens to come in contact with the hive, the entire colony is attacked and destroyed. Providing ant wells will keep away the ants. Care should be taken not to keep the colonies near or under the trees having ant nests.

 

Bee-eater bird (Merops orientalis)
These predatory birds do much harm in certain localities. They pick the bees on wings and 30-43 honeybees have been found in the stomach of a bird. Attack by these birds is mostly seen during December-January. These birds are also very useful in keeping down the insect population in a locality and hence no large-scale measures against them can be recommended. Scaring them away from apiaries is suggested.

 

Thai sac brood virus

Symptoms

All the larval instars are susceptible to the disease, earlier instars being more susceptible. Affected larvae appear slightly plumby compared to healthy ones when examined on taking out of the comb cells. The infected larvae seen stretched on their back in the cells with the head directed outwards and turned upwards like the prow of a boat. The dead larvae look like a sac filled with milky white fluid when lifted up and it ruptures even with the slight pressure releasing the milky fluid. The cadavers change their colour from white to pale yellow and sunk down to the floor of the cell and dry up in 10-15 days as brownish black boat shaped scales, which are easily removable from the cells.


The sequence of visible symptoms found in the field is:
1. Presence of unsealed cells in brood area containing diseased larvae with their head directed outwards like the prow of a boat.

2. Dead larvae are seen lying stretched out on their back on the floor of brood cells and look like a sac filled with milky white fluid when lifted up.

3. Appearance of dead larvae strewn on the floorboards, hive entrance or on the floor near the hive.

4. Mottled appearance of brood combs with uncapped cells interspersed with capped cells or cells with perforated capping.

5. Appearance of more and more dead larvae left within the cells without being ejected by the worker bees.
6. Appearance of sac like remnants of dead larvae within the cells.
7. Lack of cleaning activity within the hive.
8. Decrease in egg laying rate and irregular placement of eggs.
9. Decrease in foraging activity and presence of idling workers inside the hive.
10. Dwindling of bee population of the colony.
11. Desertion of infected hives by the bees causing total loss to the apiary.


Management

Being a virus disease there is no known remedy. However, the following measures may help in minimizing the possibilities of further spread: a) Keep colonies strong;
b) avoid exchange of hive parts, combs etc. from infected colonies to healthy colonies;

c) avoid procurement of colonies or swarms from infected areas.

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SERICULTURE
(Ad hoc recommendation)

Moriculture

Mulberry can be grown under various climatic conditions ranging from temperate to tropical. Its growth depends on many climatic conditions such as temperature, humidity, rainfall etc. A temperature range of 24-28ºC, humidity range of 65-80 per cent and 600-2500 mm rainfall are ideal for optimum growth of mulberry. The soil should be deep, fertile, well drained, clay loam to loam and with good moisture holding capacity. Slightly acidic (6.2-6.8 pH) soil free from injurious salts is ideal for the growth of mulberry.

 

Land preparation

The field is levelled and ploughed deeply before the onset of monsoon. FYM may be applied @ 10 t ha-1 for the rainfed crop and 20 t ha-1 for the irrigated crop during land preparation.

 

Method of planting and spacing
(1) Pit system (rainfed crop): Spacing 75 cm x 75 cm (pit size 30 cm x 30 cm x 30 cm)(2) Row system (irrigated crop): Spacing 60 cm x 60 cm (ridges and furrows)


Planting material

The variety K2 gives higher yield and better quality leaves. Cuttings must be prepared from shoots of proper maturity (6-8 months) and thickness with well developed buds. Cuttings of 7-10 cm length and pencil thickness with 3 or 4 active buds are ideal.

 

Planting

For irrigated crop, two cuttings should be planted at each spot along the margin of the ridge.

 

For rainfed crop, three cuttings are to be planted per pit in a triangular manner with a distance of 15 cm, keeping only one bud exposed.

 

Maintenance of the garden (1st year)
After 8 months of planting, 50 kg each of N, P2O5 and K2O should be applied per ha after weeding. First harvest can be taken six months after planting by leaf picking. Second dose of 50 kg N per ha should be applied 8 weeks after the first leaf harvest. Two more crops can be taken at an interval of 3 months, by leaf picking.
 

Manuring
For rainfed crop apply FYM @ 10 t ha-1 as a basal dose and topdress every year at the time of annual pruning. Fertilizers are applied @ 130:65:65 kg ha-1 of N:P2O5:K2O in two split doses. For irrigated crop, FYM is given @ 20 t ha-1 as basal dose. Fertilizers are applied @ 300:120:120 kg ha-1 of N: P2O5: K2O in five split doses.

 

Pruning

For rainfed crop, bottom pruning is done in May-June. Two top clippings in August/ September and December/January are also practised. Middle pruning is done in October/November. For irrigated crop, bottom pruning at 15-30 cm height in May, two top clippings in August and December and two middle pruning at 60 cm height in October and February/March are practised.

 

Pests

Tussock caterpillars (Euproctis fraterna)
Larvae eat the leaves of the mulberry plant. Their incidence is frequent during March to August. Collection and destruction of egg masses and spraying 1 per cent DDVP are effective. Waiting period is 3 days.

 

Jassids (Empoasca flarescens)

Greenish hoppers feed on the underside of the leaf, suck sap and cause hopper burn. Spraying 0.05 per cent dimethoate is effective. Waiting period is 10 days.

 

Thrips

These are frequent during summer season. Attack is severe in rainfed gardens. Spraying 0.02 per cent DDVP is effective. Waiting period is 3 days.

 

Mealy bugs (Maconelliococcus hirsutus)
It causes `tukra disease'. The affected leaves show curling and stunted growth at the growing point.

 

Scale insect

When attack is severe, branches dry and become yellow. Spraying lime sulphur solution is effective.


Leaf eating caterpillar (Diacrisia obliqua)

Appears frequently between November and January. Collection and destruction of egg masses, deep ploughing and flood irrigation to kill the pupae and application of 0.05 per cent DDVP on the leaves can prevent the attack.


Root knot disease (Meloidogyne incognita)
Common in sandy loam type of soil under irrigated conditions. Controlled by applying neem oil cake at the rate of 400 kg per ha per year in four equal split doses.


Diseases

Powdery mildew (Phyllactina corylea)

It is more common during November- February. White powdery patches appear on the lower side of the leaves.

 

Leaf rust (Ceratelicum fici)

The attacked portion of the leaves have whitish brown pustules on both sides, are deformed and non-nutritive. Infection is more in November-February. This can be controlled by spraying carbendazim 0.05 per cent or tridemorph 0.08per cent.

 

Leaf spot (Cercospora moricola)

Diseased leaves have a number of circular or irregular brownish black spots of varying size. Infection is more common in rainy season. This can be controlled by spraying 0.05per cent of carbendazim.

 

Yield

Rainfed crop : 12000-15000 kg/ha/year

Irrigated crop : 25000-30000 kg/ha/year

 

Silkworm rearing
Requirements for silkworm rearing
1. Good quality mulberry leaves
2. Rearing house of approximately 20 m2 for 100 dfls (disease free layings), with good ventilation, mild temperature (24-28ºC) and humidity (65-85 per cent).

3. Rearing equipments like chawki stand (one), wooden trays (10), rearing racks (5), chopping board (one) and knife, wooden / bamboo rearing trays (50), chandrika / netrika (mountage) (40), leaf chamber, feeding stands, ant wells, rocker sprayer, wet and dry bulb thermometer and materials like formaldehyde / bleaching powder, paraffin paper, cleaning nets, foam rubber strips, and RKO powder are required.

 

Rearing techniques

Disinfect the rearing house and equipments two-three days before rearing to prevent silkworm disease. First, wash the rearing house and the equipments with 2 per cent bleaching powder. Then spray the room and equipments with 5 per cent bleaching powder or 2 per cent formaldehyde. Keep the rearing houses closed for 24 hours for the fumes to get diffused.


First incubate the dfls (egg card) at a temperature of 24-26ºC and RH of 75-80 per cent, one day prior to hatching (blue egg stage); cover the eggs with black paper (black boxing). Next day morning, open it and expose to diffused sunlight. As the larvae emerge out, fresh tender leaves collected from the plant are chopped into 0.5 mm x 0.5 mm size and sprinkled over the hatched larvae. After half an hour, transfer the larvae to the paraffin paper spread in the chawky trays (wooden trays) using fine brush. Provide wet foam strips around and prepare a compact bed. Give another feeding in the bed. Cover with paraffin paper and stack the trays one over the other on the stand. Upto 20 layings can be brushed in a tray of 90 cm x 60 cm.

 

At the end of each instar, larvae stop feeding and cast off old skin in 18-30 hours. When the worms set for moulting, paraffin paper should be removed and spread on the bed to dry up. If there are more feeding worms, a light and thin feeding may be given. All the worms settle in 6-8 hours. During moulting, worms should not be disturbed and full ventilation should be provided. Feeding is resumed when 90 per cent of worms have moulted. RKO powder is dusted over the worms 30 minutes before feeding. After two consecutive feedings, the larvae with the net are transferred to a new tray. Mature larvae stop feeding and prepare themselves for spinning. Its body becomes translucent, shrinks in length and constrictions appear on fourth and fifth segments. They move towards the periphery of the trays. Such worms are picked and transferred to Chandrika / Netrakae. About 1000 worms (400-450 larvae/m2) can be mounted in a mountage. Mount the entire larvae within a maximum period of 48 hours and provide sufficient ventilation during spinning. Cocoon should be harvested on the fifth and sixth day after mounting. In rainy and cold seasons, it should be delayed for one more day. The cocoons are collected from Chandrika and transported in light gunny bags to cocoon market. The cocoon should be marketed immediately after harvest, so as to avoid adult emergence. Under average conditions, 100 dfls of bivoltine will yield 40-60 kg cocoons and cross breed will yield 30-50 kg cocoons.


Diseases

Pebrine

It is the most destructive disease of silk worms and is caused by protozoa, Nosema bombyscis. The worms become inactive with poor appetite, the skin becomes wrinkled and moulting becomes irregular.

 

Flacherie
It is caused by bacteria and poor rearing conditions like high temperature, high humidity, poor ventilation, bad leaf quality, over feeding etc. aggravates the disease. Digestive and circulatory systems are damaged and the symptoms are loss of appetite and diarrhoea.

 

Grasserie
Mostly seen in ripening larvae. Caused by Borrelina virus. Infection is induced by extreme low and high temperature. Swelling of the inter-segmental region, shining skin, rupture of body wall, oozing of body fluid and endless crawling are symptoms. Such worms do not moult and spin.

 

Muscardine

The fungi Beauveria bassiana, Spicaria prasina and Isaria farinosa are the causal agents. The infected larvae lose appetite. Specks of oozing oily substance without any clear-cut margins appear on the skin. Body generally hardens and becomes stiff.

 

Prevention and control

1. Disinfect the rearing room and equipment before rearing.

2. Use only disease free layings from authorized agencies.

3. Dip the egg cards in 2 per cent formalin solution for 20 minutes before incubation.

4. Collect undersized larvae and destroy regularly by burning or burrowing in soil.
5. Feed good quality leaves of correct stages.

6. Avoid over feeding and under feeding

7. Clean the bed every day and burn the infested litter.

8. Use RKO powder at every moulting before resumption of feeding.

9. Maintain humidity only to the desired level.

 

Pests
Uzi-fly (Trycholyga bombycis)
It is a serious parasite of silkworm larvae and pupae causing heavy loss. Adult is a large fly with prominent black and grey stripes. The fly prefers later instars to the earlier ones for oviposition.

 

Management

Prevent the entry of fly into the rearing room by providing wire mesh or nylon net on doors and ventilators. Burn the parasitized larvae. Apply chlorpyrifos on the ground and crevices of walls of rearing house. Other pests include ants, lizards, rats, squirrels, dermestid beetles and birds.

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RODENTS AND THEIR CONTROL

(Ad hoc recommendation)

 

Rats are important non-insect pests and can be grouped into two different groups as domestic rats and field rats.

Domestic rats

 

These are found near human dwellings.

 

1. House rats (Rattus rattus): There are two subspecies; one with white belly and the other with grey belly. Tail length is more than the length of head and body. They are found in houses and eat anything that man eats. They also cause qualitative damage by deposition of faecal matter, urine and hairs. It damages gunny bags, plastic containers, clothes, electric wires etc. House rats
damage tender coconuts and cocoa pods in the fields. Tey also act as carriers of several human and animal diseases.

 

2. House mouse (Mus musculus): Fur is short without spines. Tail is almost naked and larger than head and body. The mouse is very active and is found in houses and gar-dens. It can climb up walls. It damages clothes, plastic containers and food materials.

 

3. Large bandicoot rat (Bandicota
indica): This is the largest domestic rat. Fur is coarse. Tail length is almost equal to the body length. Body weight ranges from 750 to 1000 g. It damages all tuber crops. It also damages concrete buildings by making burrows under the basement.

 

Field rats

1. Large bandicoot rat (B. indica): Large bandicoot rats are also seen in the field. So this can be considered both as domestic and field rat.

 

2. Lesser bandicoot rat (B. bengalensis): It is a short tailed mole rat. Tail length is only 70 per cent of the body length. Fur is short and coarse. It is seen making burrows in the paddy field bunds and also in areas where crops like tubers, vegetables, coconut and young rubber are cultivated.

 

3. Field mouse (Mus booduga): Fur is short and coarse and is mostly found in gardens and fields.Tail is slender and nearly naked. Tail length is shorter than body and head. The burrows of this species are found in the paddy fields. They are found feeding on paddy grains in the mature crop as well as on seeds sown in the nursery.

 

4. White rat (Tatera indica): More than one rat per burrow is common in this species. The eyes are large.The tail is longer than the body and is provided with a terminal tuft of long hairs. It is double coloured.

 

5. Long tailed tree mouse (Vande-leuria oleracea): The fur is soft and tail is much longer than the body. They are found in most parts of India inhabiting trees and shrubs. They damage the inflorescence of arecanut and leafy vegetables by cutting its leaves.


6. Norway rat (Rattus norvegicus): These rats are found in waterlogged areas. This is a medium sized rat with tail more or less equal to the length of the head and body. These rats damage paddy crop. It cuts the plants at the base and chews the cut portion. Maximum attack is at the booting stage. The attack ceases after initiation of flowering. The damage is usually observed in patches away from the field bunds.

 

7. Soft furred field rat (Millardia meltada): These rats are found in cultivated field in pairs or small groups of 5 or 6. They are soft furred without spines. These rats cut the rice plants in the transplanted crop. The damage starts at the time of planting and continues up to harvest. The tillers are cut at the water level.


8. Bush rat (Golunda elliotti): These rats are seen in places near forest area. They live under bushes in nests. These rats are destructive to coffee plants. They feed on their buds and flowers. They damage paddy by cutting the plants in dryland paddy areas.


Integrated control of field rats
Rats cause considerable damage to agricultural practices and other human possessions in addition to acting as carriers of several human and animal diseases. Diseases like bubonic plague and weils disease (due to contamination of food by the urine of rats) are caused by rats. It is necessary that the importance of rat control be understood by all. An integrated approach to control rats involves the joint utilisation of all feasible control measures in a complementary manner to maintain the rat population at a very low level. Integrated control of field rats involves the following: (a) preventing their entry into a region or a building by putting up mechanical barriers or treating with repellents; (b) encouraging predators such as snakes, cats, dogs, mongooses etc.; (c) causing death by a variety of methods.

 

Methods of control
Environmental control

In this method of control rats are rendered to a hostile environment in which they cannot survive. The mud walls in villages may be replaced by thorny hedges thereby preventing the rats from making burrows. Good house keeping is regarded as the most economical and effective way of reducing rat population. Proper sanitation should be maintained by keeping food material inaccessible to rats in rat proof containers. The heap of garbage and sweepings in streets and towns should not be kept for a long period. Designing rat proof godowns and other buildings is another step to ensure environmental control.

 

Poisoning

Three types of poisoning are usually employed to control rats.

1. Acute poisons are those that can kill rats with a single dose; e.g. zinc phosphide.
2. Multiple dose or chronic poisons require repeated ingestion over several succes- sive days; e.g. anticoagulants.

3. Fumigants are gases and are usually pumped or released from pellets or tablets put in through burrow entrances.


Zinc phosphide
It is a dark grey powder and its toxic action is due to release of phosphine gas. When it is ingested, phosphine is released causing injury to the kidneys, liver and lungs followed by death after a few hours. Zinc phosphide is used in food baits containing 2 per cent active ingredient.

 

Pre-baiting for 3-4 days consecutively is necessary to overcome bait shyness. For pre-baiting and baiting, the same carrier material has to be used. Crushed wheat, maize, bajra, puffed rice, popcorn or rice mixed with a little jaggery and oil are excellent carriers. To prepare the carrier, 95 parts by weight of cereal ingredient is to be mixed with 5 parts of jaggery.

 

For baiting, zinc phosphide is mixed with groundnut oil and carrier in the ratio 2:2:96 by weight. At each bait station, 30-40 g of the bait mixture will have to be exposed. The stations may be selected in areas where rats are frequent, such as areas around kitchen, store and in homesteads. Expose baits in the evening and collect them in the following morning. Conduct baiting for three successive days.

 

Repellents

Chemical repellents include malathion and cyclohexamide which are repellents to house rats.


Biological control

Both field and domestic rats are subjected to attack by a range of predators, parasites and pathogens. The predators include cats, dogs, snakes, owls, mongooses etc. The practice of rearing cats in house has been found to adversely affect rat population. The utilization of microbial pathogens has not proved successful in any part of the world.

 

Trapping

Trapping is the oldest method of controlling rodents. Almost any trap will catch some rats, but the response varies with different species. The rats are easily caught in cage or box, but a rat trapped in such trap will be exposed to other rats which develop trap shyness and they avoid such type of traps. The most effective rat taps are those, which can completely conceal the rats trapped in it; e.g. Moncompu trap. The rat traps can be grouped into a few categories.


Live traps (cage or box trap)

1. Automatic traps: These have counter balanced entrances. When an animal enters this type of traps, its weight makes it fall into a cage below. The counter balance on the trap door brings it back into place, leaving the rodent in the cage. These are intended to catch more than one rat; e.g. wonder trap.

 

2. Remote triggered trap: These work by upsetting a delicate balance when the bait stick is disturbed or when the weight is put on a treadle. Common type of this is the box or cage trap that captures one rat at a setting. A box trap is a wooden or metal box open at one or both ends, having one or two doors. Some have one or both will have overhead trigger on which bait is fastened and the door is released when the rat works on the bait. Others have a treadle in the floor on which the rat steps to drop the door

 

3. Glues: A form of trapping in which a sticky substance entangles the animal.

 

4. Pot traps: These traps are extensively used for catching rice field rats. This trap

consists of a wooden plank, a mud pot of 10 inch diameter, a metal strip which carry bait and a `Y'shaped wooden peg to which needle is tied; e.g. Moncompu trap.


The trap is to be set up in rice fields, after placing the base plank above the canopy level on a specially erected platform, on poles. The rats attracted by the bait climb over to the base plank and try to snatch off the bait tied on to the metallic strip. Slight disturbance of the strip dislocates the wooden needle from the strip slot and causes the pot to fall down abruptly over the rat. The pot and the plank are tightly held and removed in that position and immersed in water after inversion for killing the trapped rat. Since the live rat does not see the captured ones, they do not develop shyness against this type of mechanical trap.

 

5. Snap traps: Most of the rat traps fall within this category and are widely used for trapping rats. These kill the rat instantly by snapping shut when the rat nibbles at the bait placed in the middle of the open trap. These are variously called as "break back traps", "guillotine", "spring traps", "saw toothed traps" and "bamboo traps" depending upon the materials used in making them.

 

6. Kerosene tin trap: It is made by cutting the top of the tin and filling it with water up to 15 cm from the top. Chaff is floated on the water surface so that the rat cannot see water. Attractive and strong smelling bait like dry fish, fried coconut etc. is pinned on to a piece of cork or lightwood and floated on the chaff. A plank is leaned against the side to enable the rat to climb to the top. Seeing no water and eager to get the bait the rat jumps on to the chaff and gets drowned.

 

Success or failure of trapping is dependent up on the following factors.

 

a. Placement: Traps must be placed where animals will regularly encounter them.

b. Concealment: It is not advisable to use new shining traps against rats. To overcome trap shyness it may sometimes be necessary to cover the trap with a slight coating of paper or dry leaves that does not interfere with the trigger or action.
c. Size and design: Traps should be neither too small nor too large for the anticipated catch.

d. Mechanical conditions: Putting out traps that are in poor working conditions is a waste of time and effort.
e. Number of traps: Large number of traps relative to the expected size of the rodent population should be used.

f. Bait used: Fresh aromatic bait that is most attractive to the largest species should be used. Food grains in the houses should be properly covered so that the rat finds only the food in the trap.

Trapping is the preferred method of control in the houses and office building, because animals that get killed can be easily removed. Traps can be used profitably to deal with poison-shy and scattered survivors of poison campaign.

 

Control of important species of rats
Lesser bandicoot rat: These attacking tuber crops can be easily controlled by poison baiting in rodent burrows. Firstly, locate the burrows in the field. Open the burrows to a length of 30 to 45 cm. The rats will come and close the burrows with soil within 30 minutes. Then it can be again opened and poison bait can be inserted into the burrow.


From bait preference studies indicate that, prawn powder as the most effective bait. Dry prawn available in the market is heated and powdered. A few drops of vegetable oil are added and zinc phosphide 1-2 per cent is mixed with the bait. This zinc phosphide bait can be put inside the burrow preferably on a dry leaf. No pre-baiting is necessary for these rats in the garden lands since it has no bait shyness.


Norway rat: The most effective method of control has been found to be the Moncompu trap. Firstly, fresh rat-damages in the field have to be located. The rats have a habit of visiting the same area on subsequent days. Hence the traps should be placed in such spots.

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BIOCONTROL OF SALVINIA (Salvinia molesta)

 

Release of Cyrtobagous salviniae weevils is found effective for the control of salvinia. Even one pair of weevil is sufficient for establishment in a locality. But for practical consideration 50 to 100 weevils are recommended for release in a particular area. When collection of weevil is not possible, about one kg of infested salvinia can be used as the inoculum. Release may preferably be made whenever tender salvinia growth is available. If the plants are very old, they may be removed mechanically to promote re-growth and then weevils are to be released. Almost 100 per cent control of the weed will be obtained in a span of 12-18 months.

 

The rate of natural dispersal of the weevil is rather slow and hence it is desirable that the infested weed mats are redistributed at periodic intervals. In canals used for navigation, the rate of spread of the weevil is found to be quite adequate.

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BIOCONTROL OF PAPAYA MEALY BUG USING PARASITOID

 

Papaya mealy bug _ Paracoccus marginatus (Pseudococcidae) : Papaya mealybugs colonise lower side of the papaya leaves along the veins and later cover the fruits. Due to the mealy bug infestation, the younger plants are killed outright.

 

Biological control: Acerophagus papayae (Encyrtidae) is a parasitoid imported from Puerto Rico. The parasitoid successfully suppressed the mealybug population in Kerala. The parasitoid is very specific and did not colonise other species of mealybugs. Release rate is 25 to 50 numbers per plant. The parasitoid is parasitizing the second instar nymphs of mealybugs. It is very active and have good host searching ability and suppress the mealybug within 3 to 4 months depending upon the size of the colony.

 

Mass production of the parasitoid: The parasitoid can be successfully mass produced in the laboratory on papaya mealybug colonies grown on potato sprouts and shoots. Two month old potatoes are procured, washed in water, disinfected using 5% Sodium hypochlorite solution. Make slight cut on the potato and treat in Giberelic acid 100 ppm solution for half an hour. After air drying keep the potatoes on sand and cover with black cloth for germination. Good sprouts are produced within two weeks for mass culturing mealy bugs.The parasitoids are then released to the colonies of the mealy bug. A. papyae has very less pre oviposition period, sex ratio is 1:1, fecundity 50-60, Total life cycle is completed in 16-20 days.

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ECOFRIENDLY MANAGEMENT OF WATER HYACINTH
(Eichhornia crassipes) IN WATER BODIES
 

Water hyacinth in water bodies can be managed by spraying 5 per cent Cashew Nut Shell liquid (CNSL) emulsion followed by spraying 40 per cent Wetable Powder formulation (WP) of Fusarium pallidoroseum (5 per cent). Spraying may be repeated with WP 5 per cent alone, after 2 weeks if any new sprouts develop.


Preparation of 5 per cent CNSL emulsion

To prepare 10 litres of 5 per cent CNSL emulsion, 500 ml of CNSL and 50 g bar soap are required. Slice the bar soap and dissolve in 500 ml of water. Pour 500ml.of CNSL slowly and stir vigorously to get a good emulsion. Dilute this one litre solution by adding 9 litres of water to get 10 litres of 5 per cent CNSL emulsion.

 

* A minimum of 30 minutes may be given between the application of CSNL and Fusarium pallidoroseum.

* In moving water bodies fencing with rope and coconut leaf is recommended.

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BIOCONTROL AGENTS AGAINST PLANT PATHOGENS

Arbuscular mycorrhizal Fungi (AMF)
Inoculation with AMF at the time of planting in the nursery or main field improves the growth and tolerance of crop against root pathogens, particularly Phytophthora, Pythium, Rhizoctonia and root nematodes of black pepper, cardamom, ginger, turmeric, cowpea, rice and transplanted vegetables.

 

Trichoderma

Biocontrol of soil borne plant pathogens involves mass introduction of antagonistic microorganisms in the soil. Trichoderma spp. is a group of broad-spectrum antagonists subjected to detailed studies for their potential as biocontrol agents. They are effective against the quick wilt of pepper (T. viride T6, T. longibrachiatum T2), rhizome rot of cardomom (T. longibrachiatum T2, T. virens T9) and ginger (T. viride T10). A non-axenic system, viz. neemcake-cowdung mixture is used as food base for Trichoderma spp.


Dry neem cake and cowdung are to be powdered and mixed at 1:1 ratio to get a coarse texture and then moistened by sprinkling water. Add the commercial preparation of Trichoderma spp. (available in polythene packets) @ 1-2 kg per 100 kg of neemcake cowdung mixture. After thoroughly mixing, cover it with a perforated polythene sheet or ordinary newspaper and keep it in shade for 4-5 days for multiplication. Again mix well and keep for three more days for further multiplication. This preparation is ready for incorporation in the soil. Cowdung alone can also be used as the food base; but, since neem cake is found to be a better substrate, a mixture of the two is found better than using cowdung alone. If cowdung alone is used, mixing has to be done at 5 days interval and it will be ready for use only on the 15th day. This Trichoderma incorporated neemcake- cowdung mixture can be used in the potting mixture in nursery beds and in the field; i.e. wherever cowdung is used as a manure.

 

Trichoderma harzianum is recommended by fortifying 50kg farmyard manure or neem cake with 1kg of the mother culture and incubated for 10-15 days before application in the field (@ 1kg/vine). The mother culture in liquid formulation can be incorporated with sterilized coir compost @ 1l/20kg and apply @1kg/vine as above.


Fluorescent pseudomonas

(ad hoc recommendation)
Fluorescent pseudomonas are a group of bacteria very effective against disease incited by species of Phytophthora, Pythium, Rhizoctonia, Fusarium, Colletotrichum, Ralstonia and Xanthomonas in various crop plants in the nursery as well as in the main field.

 

Two isolates of Pseudomonas fluor-escens (P1 and P14) have been developed by the Kerala Agricultural University for the disease management and growth promotion of crop plants. This is found highly effective for the management of foot rot and fungal pollu of black pepper, sheath blight and bacterial leaf blight of paddy, bacterial leaf spot and Phytophthora infestation in betel vine, bacterial wilt of solanaceous vegetables, bacterial leaf blight of anthurium and Colletotrichum and Phytophthora infestation in vanilla and rhizome rot of ginger. The organism significantly improves the growth and biomass production of crop plants.

 

Application of Pseudomonas fluorescens at the rate of 10 g formulation (1010 cells per gram) mixed with 2 kg of well decomposed farmyard manure or compost and applied in the basin of the vine in the field can also help control foot rot.

 

Method of application

The time of application and the frequency of application may vary depending on the crops. The application may be repeated based on the intensity of the disease incidence.

 

The talc-based formulation at 1-2 per cent level may be used for soil drenching and spraying. Seedlings/cuttings are treated with Pseudomonas culture by dipping the root/tip of cuttings in slurry of Pseudomonas (250 g in 750 ml for 20 minutes). For seed treatment in paddy the talc based culture may be added to the water used for sprouting at the rate of 10 g per kg of seed.

 

For transplanted crop, root dip treatment at the time of transplanting, followed by a spray 30 days after transplanting. For black pepper, drenching the nursery plants immediately after planting followed by one or two sprays depending on the extent of disease. For managing foot rot of pepper in the main field, drenching the base of the vine and spraying the plant with Pseudomonas

culture at the rate of 10 g/litre at the onset of monsoon can be practised. A second spray may be given, if necessary, during the mid-monsoon period.

 

Chemical fertilizers and plant protection chemicals should not be used along with biocontrol agents.

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SOIL SOLARIZATION

 

Solarization is a method of hydrothermal disinfection. This is done by covering moist soil with transparent polythene sheet and exposing it to direct sunlight during the hottest period of the year.

 

Methods of solarization

a. Nursery bed

The nursery bed for raising seedlings is to be levelled and pebbles present on the surface removed before solarization. Incorporate the required quantity of organic manure in the soil and irrigate at the rate of 5 litres per m2. Cover the beds with 100-150 gauge transparent polythene sheets. Seal the edges of the sheet with soil to keep it in position in order to maintain the temperature and moisture inside the polythene mulch. Adequate care is also to be taken to see that the sheet is in close contact with the surface of soil to prevent the formation of air pockets between the soil and polythene sheet. Keep the sheet in this way for 20-30 days. Protect it from stray animals and birds. After the period of solarization, remove the sheet and the bed is ready for sowing and transplanting.

 

b. Potting mixture

The required type of potting mixture is to be prepared as per the recommended practice. Spread this mixture on a levelled ground to a height of 15-20 cm. Moisten with water using a rose-can and cover the soil with polythene sheet and solarize for 20-30 days as described above. After solarization, the soil can be used for sowing/planting. This method is found to be very effective to raise disease free pepper cuttings.


c. Main field
Solarization can also be effectively used for the control of soil borne diseases in the main field. The land used for planting is initially prepared to a fine tilth and pebbles removed. Solarization and planting can then be done as already described. All the other agronomic practices are to be followed as per the package of practices recommendations. Biopesticides and fertilizers can be

incorporated in soil after removing the polythene sheet.


Hints for solarization

1. Solarization is to be done in open field without any shade.

 

2. Transparent thin polythene sheet (100 to 150 guage) is to be used, as it is both cheaper and more effective in heating due to better radiation transmittance than thicker sheets.


3. Summer months are more suitable for solarization.


4. Soil should be kept moist during solarization to increase the thermal sensitivity of resting structures of soil-borne plant pathogens and weeds, and to improve heat conduction.

 

5. Solarization period may be extended to one month or more to ensure pathogen control at deeper layers.


6. Summer showers will not affect solarization. However, excessive seepage of water into the bed during solarization should be avoided.

 

7. Potting mixture should never be heaped and solarized, as this will drastically reduce the efficiency of the technique.


8. Soil should be in good tilth allowing close contact between the plastic sheet and the soil to prevent the formation of air pockets, which will reduce heat conduction.


Benefits of solarization
1. Control of fungal pathogens: Several soil borne pathogens can be controlled by solarization. This includes fungi like Pythium, Phytophthora, Fusarium, Rhizoctonia etc.

 

2. Control of nematodes: Population reduction of nematodes like Meloido-gyne, Heterodera, Xiphinema, etc. can be achieved by solarization.
 

3. Control of weeds: A number of commonly occurring weeds particularly annuals can be effectively controlled by solarization. These include, among monocots, Cynodon dactylon, Cyperus rotundus and Digitaria ciliaris and among dicots, Crotalaria muconata, Indigofera hersuita and Noxia sp.
 

4. Plant growth response: Increased growth response is observed in plants cultivated in solarized soil. This is mainly evident as increase in plant height, number of leaves, better root formation, increased root nodulation in legumes and yield.

 
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MUSHROOM Cultivation

 

Species of Pleurotus, commonly known as oyster mushrooms, grow saprophytically under natural conditions on trees, dead wood, stumps and branches. Today several species of Pleurotus are commercially grown in many parts of the world. The tropical climate prevalent in the state is ideal for mushroom cultivation. Species of Pleurotus and Volvariella can be successfully cultivated in the State all round the year on a variety of agro-wastes like saw dust, vegetable and paper wastes, oil palm pericarp waste and straw. But the most suitable substrate is found to be paddy straw.


Variety
Ananthan is a short duration variety of oyster mushroom released from KAU. It is an inter-stock hybrid of Pleurotus petaloides with firm flesh, pure white colour and is resistant to pest and diseases. It has good cooking quality as well as consumer acceptability and can be grown on wheat, paddy and sorghum straw. On an average, it takes eight days from spawning to harvest. Yield potential is 800 g per kg straw.

 

Method of cultivation

Polythene bags or tubes of 30 cm x 60 cm size and 150-200 gauge thickness are taken for filling the substrate. If the tubes are used, the free-end is tied with a string. Seven to eight holes of 0.5-1.0 cm diameter are made all over the bag for aeration. One kg of well dried, one year old paddy straw is cut into small bits of 5-8 cm in length and immersed in water for 18 hours. Then the soaked straw is taken out from water and kept inside the basket for 1-2 hours to drain away excess water. The soaked straw is kept under boiling water (100ºC) for 30-40 minutes for surface sterilization or to achieve pasteurization and then taken out and kept inside the basket to drain excess water and is allowed to cool to room temperature. The pasteurized straw is ready for filling the bags. Instead of straw bits, small round straw bundles of 20 cm diameter are also used for filling the bags. This method is followed to save time and labour. Now the perforated polythene bag is filled for about 5 cm height with the above processed straw and pressed with hand for making it even. Care should be taken to fill the bags as compactly as possible for the proper growth of mycelium. For getting maximum yield, 2-2.5 per cent (125 g) of spawn is used. Spawn is taken out from packets and kept inside a clean container or paper. From this, one tablespoon full of spawn is sprinkled over the filled straw around the peripheral region. A second layer of processed straw is filled and spawned as above. Repeat the process as above until the soaked straw is finished. Every time before spawning, press the straw with hand for making it compact. If bundles are used for filling the bags care should be taken to keep the bundles inside the bag as compact as possible without leaving any space in between the bundle. Finally the bag is closed tightly with twine and beds are kept undisturbed for spawn running for about 15-20 days inside the rooms, thatched rodent-proof sheds or in verandas. The best temperature and humidity for spawn running ranges from 28-30ºC and 80-85 per cent respectively. The beds can be arranged over a platform or in shelves. The spawn running can be judged from the whitish growth covering the straw completely. Periodically observe the beds and discard the contaminated ones.

After 15 days when the spawn running is complete, remove the polythene bag by cutting it with blade and keep the bed for sporocarp formation. The opened beds are kept in well-ventilated rooms. Relative humi-dity of the room should be 80-85 per cent. If temperature inside the room rises above 30ºC, the room should be sprinkled with water to lower the temperature. Diffused light is essential for normal fruiting. Pinhead formation starts on 20th day and 2-3 days are required for the maturation of the fruiting body.


Cropping and yield

Matured and fully opened sporocarps are harvested by placing the thumb and forefinger near the base of the fruiting body and twisted in clockwise direction to get it detached from the mycelium. An average yield of 500-700 g can be harvested from 1 kg of straw. The spent straw can be used as enriched cattle feed.


Management of Pests and contaminants of Oyster mushrooms in Kerala

• Maintain the pH of the water used to soak the substrate at 8.0 by adding lime.
• Cover the holes with cotton or alternatively put 30 - 40 pin pricks on the polythene cover of the mushroom bed.

•Spray 2 per cent garlic in and around thevicinity of mushroom beds

• Spot application of Carbendazim (at the rate of 50 ppm) in mould affected partsof the bed.

• Erect Yellow Light traps for every 25m 2 at a height of 60 cm from the ground in the mushroom house.

• Hang an yellow bulb (15W) in between two card board pieces (15 cm x15cm size) coated with mustard oil. Switch on the bulb from 5 pm to 8 am. Remove insects trapped on the sticky surface everyday.

 

Cultivation of paddy-straw mushroom (Volvariella volvacea)
The paddy straw mushroom can be successfully cultivated in the plains of Kerala throughout the year where the temperature ranges between 28-32ºC. The straw beds can be laid out in sheds, veranda of buildings and even under shades of trees during summer. Beds should not be kept under direct sunlight. Prepare a raised platform of 1 m long and 0.5 m broad with wooden planks or bricks. Ten to fifteen kg of well-dried and hand-threshed straw is required to raise a single standard bed. For spawning this bed, two bottles of spawn and about 100 to 150 g of red gram powder are needed. First the straw is made into twists of about 5 to 8 m long and 20-25 cm diameter. The twists are tied into small bundles and are kept immersed in clean water in tanks for about 6 to 12 hours. After this, the bundles are taken out and kept aside for some time to drain the excess water. The bundles are untied and the straightened twists are placed length-wise over the platform in a zigzag fashion. The twists are placed as close as possible. Keep another layer over the first layer crosswise. These two layers form the first layer to be spawned. Break open the spawn bottles and carefully divide the spawn into small bits of 2-2.5 cm thick. Place these bits of spawn all the rate of along the periphery of the bed, about 5-8 cm away from the edge and 10 cm apart. Sprinkle a teaspoon full of coarsely powdered red gram powder before and after spawning the first layer. Build the next layer with one row of twist as done before and spawn it. Make successive layers until the straw twists are finished. After placing the last of twists, press the bed thoroughly from the top in order to drain excess water. Make the bed as compact as possible and cover with a transparent polythene sheet to maintain the temperature and relative humidity within the bed. Place another wooden plank over the bed and keep 4-5 bricks above the plank to get more compactness. Keep the bed undisturbed for 6-7 days. Slowly remove the sheet and observe the moisture level of the straw. If the moisture is excess remove the sheets for half an hour and then cover it again as before. Small white round pinheads appear all along the sides of the bed after 7 days and mature into button and egg stage on 9th day. Harvest the mature sporocarps in egg stage. About 2-3 kg of mushrooms can be harvested from 10 kg of straw. Cropping lasts for 2-3 days. After the harvest, the spent straw can be sun-dried and used as cattle feed.

 

Instead of twists, the beds can be laid out using small bundles of straw each weighing about one kg. Place four such bundles of straw side by side over the platform with loose ends towards the same direction. Over this, place another four bundles, the loose ends towards the opposite direction. These eight bundles form one layer, which is to be spawned as in the case of twists.

 
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TISSUE CULTURE PROPAGATION OF CROPS
(Ad hoc recommendation)

 

Plant tissue culture is the in vitro culture of plant cells, tissues and organs under aseptic condition in defined or semi-defined media. Tissue culture techniques are increasingly being used for the rapid vegetative propagation of plants. It helps in the mass clonal propagation of crop plants. It is useful for plants which do not set seeds or where the viability of the seeds is poor. Even when conventional methods of vegetative propagation are commercially acceptable, tissue culture propagation can be adopted as it has definite advantages. It offers an extremely rapid rate of multiplication. The geometric progression of tissue culture propagation makes it possible to produce millions of plants from an initial explant in a few months. It can speed up the process of establishing new varieties. Only a limited quantity of plant tissue is required as the initial explant. Tissue culture propagation ensures the availability of plants throughout the year. It helps in the production of uniform progeny from cross-pollinated plants. Disease free planting materials can be made available to the farmers. Special laboratory facilities and technical skill are essential for adopting this technique for mass multiplication of crop plants. Training in tissue culture is offered by various research organizations in Kerala.

 

Procedure
Pipette out the required volume of stock solutions of chemicals into a one litre glass beaker. Add components like sucrose and myo-inositol as solid and allow them to dissolve. Make up the volume to approximately 950 ml with distilled water. Adjust the pH to the required value (5.6 to 5.8 for Murashige and Skoog basal medium) with a few drops of either alkali or acid, using a pH meter. Add the required quantity of agar and make up the volume to 1.0 litre. Pour the solution into a glass beaker and heat, while stirring, until the agar is dissolved. Dispense the medium (5 to 15 ml) in test tubes or flasks and plug with cotton. Plastic lids or aluminum foil may also be used for the purpose. Culture jars may be plugged with plastic lids. Autoclave the vessels containing culture medium for 15 minutes at 1.06 kg/cm2 pressure (121ºC). While using a pressure cooker, wait for the continuous flow of pure steam, put the weight and sterilize for 20 minutes. Explants collected from field grown plants will have to be disinfected before inoculating in the culture medium. The explants are washed in running tap water first and then in soap solution. They are then surface sterilized and trimmed using sterile knives. The commonly used surface disinfectants are sodium hypochlorite (0.1 to 2.0 per cent for 15 to 30 minutes) and mercuric chloride (0.05 to 0.1 per cent for 3 to 20 minutes). The efficiency of the surface sterilant can be increased, by adding a few drops of surfactants. After surface sterilization, the explants should be washed with sterile distilled water four to five times to remove the residues. The explants are then transferred to the sterile culture media in vessels. This process is called inoculation. Surface disinfection and inoculation must be carried out in a laminar airflow chamber. This equipment can filter the air through a high efficiency particulate air (HEPA) filter of very small mesh size. This will remove bacteria and fungal spores. The steady outward flow of filtered air will ensure a sterile zone in the equipment, suitable for aseptic manipulations. The needles, forceps, blades and petri-dishes used for the manipulation of explants should be pre-sterilized.

 

The tools used in the airflow cabinet may be kept dipped in 70 per cent ethanol in a beaker and periodically flamed over a spirit lamp. After inoculating the explants in suitable culture media, the cultures are incubated in rooms under controlled conditions of temperature (26 + 2ºC), light (200 lux, 18 hours) and humidity (60-80 per cent). Response of an explant largely depends on the composition of the culture medium. There are several basal media, which can be used for various needs with necessary modifications. The basal medium is selected to suit the plant species and the method of in vitro culture. In general, culture medium consists of salts of major and minor nutrient elements, vitamins, amino acids, plant growth substances and a source of carbon. The established cultures are sub-cultured to fresh media at intervals of 3 to 5 weeks. The media provided at each subculture decide the response of the tissue. Hardening the plantlets to make them adapt to the outside environment is a critical process, essentially due to the anatomical and physiological peculiarities of the plantlets. A period of humidity acclimatization is necessary for the newly transferred plantlets to adapt to the outside environment, during which the plantlets undergo morphological and physiological adaptations, enabling them to develop typical terrestrial plant-water control mechanism.

 

Tissue culture techniques for mass multiplication have been standardized for crops like banana, pineapple, papaya, black pepper, cardamom, vanilla, orchids, anthurium, gladiolus and several medicinal plants. The commercial adoption of tissue culture clonal propagation is feasible only when the rate of multiplication is satisfactory and the cost of plantlets is acceptable to the farmers. Protocols for the tissue culture propagation of a number of crops like red banana, nendran, pineapple, orchid and anthurium, black pepper, vanilla, medicinal plants etc. have been developed at the Kerala Agricultural University and are available for commercial adoption.

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Improving the KEEPING QUALITY OF
FRUITS AND VEGETABLES

(Ad hoc recommendation)

 

About 30 to 40 per cent of the harvested fruits and vegetables are estimated to be lost due to improper harvesting, handling, storage and transportation in India. If proper care is taken during these operations, the loss can be minimized to some extent. Some of the techniques, which can be adopted, are as follows.


Harvesting

a) Harvesting must be done at the appro-priate maturity depending up on the marketing distances and purpose.

b) Harvesting must be done preferably in the morning hours or late evening to avoid exposure of the produce to excessive heat, which will hasten spoilage.

c) Harvesting must be done preferably with proper harvesting devices suited to the commodity. For example, mango harvesters with cutting edges and plastic net can prevent the damage during harvest and collection.

d) Avoid impact shock while harvesting fruits from tall trees; eg., jackfruit, mango, etc. which will cause bruising, leading to infection.

e) Avoid too loose or too tight packing in gunny bags while transporting harvested produces to minimize bruising.
 

Packing

a) Wash the harvested produce in plain water or in chlorinated water to clean it of the adhering mud, dirt and residual pesticides.

b) Remove the infested, rotten and spoiled friuts.

c) Grading the produce can improve market acceptability. This can be done at farmer's level or at collection points to suit the standards established by individuals, industry or government. Grading will also increase farmer's bargaining power, as they are likely to get premium prices for better-grade products. Similarly buyers can choose the grades they wish to buy. Possible grading can be based on colour, shape, size, weight etc. of the commodity


During storage

a) Pre-cool the commodity immediately after harvest to reduce the field heat.
b) Pre-packaging the commodity into unit packs can reduce the handling losses.

 

Some of the packaging techniques are (1) Packing of banana hands at 0.2 to 0.4 per cent ventilation with polyethylene cover of 150 gauge can increase the keeping quality upto 10 to 12 days under ambient conditions. (2) Packing fresh mushroom (Pleurotus sp.) in 100 gauge polypropylene pouches without any ventilation can extend the storage life upto 36 hours at room temperature and up to 7 days under refrigerated conditions. (3) Fresh tomato can be stored up to 25 days under ambient conditions when packed with 35 to 40 per cent moistened saw dust in the ratio of 1 : 0.5 (tomato : saw dust). (4) Fresh mature and ripe sapota can be stored up to 6 days under ambient conditions when individually wrapped with cling film.
 

General storage methods practised to extend the keeping quality are:

1. By storing the commodity under optimum/ low temperature and humidity.

2. By skin coating using wax emulsion containing permitted fungicides at optimum concentrations.
3. By adopting controlled/modified atmos-pheric storage modifying the oxygen/ carbondioxide ratio within the package.

4. By sub-atmospheric pressure storage.
5. By ventilated storage using ventilated films/bags.
6. Using evaporative cool chamber constructed to store temporarily the harvested produce at the field before marketing.

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LOW COST TECHNOLOGY FOR IRRIGATION

(Indigenous auto irrigator for irrigating potted plants)

 

Indigenous auto irrigator can be fabricated by fitting certain low cost accessories in ordinary garden pot. First of all plug the holes of the garden pot with corks provided with holes. Insert hospital drips through these holes. Garden pots designed in this manner can serve as auto irrigator. One auto irrigator can serve as water source for a maximum of six pots. Place the irrigator at a level

above plant height and arrange the potted plant around this auto irrigator. Plants are irrigated by exploiting gravitational force. Adjusting the regulator attached to the hospital drips can regulate the flow of water. Irrigate the pots to bring it to field capacity. Daily loss of water from the pots can be computed. The flow rate can be adjusted according to water requirement of the plant.


 

KAU Micro sprinkler
KAU Micro sprinkler is a farmer friendly irrigation system, simple in design, with less clogging susceptibility, ensuring uniform wetting of the basin of the crops. The main component of the system is the rotating sprinkler head, made of a small piece of 12mm/8mm dia. LDPE pipe plugged at both ends by end caps. The length of pipe is 6cm for 12mm pipe and 8cm for 8mm pipe. Nozzles of 1mm diameter are drilled on opposite sides of the pipe, 5mm away from both ends, at 900 from bottom. It is centrally attached to a 6mm micro tube and then to the lateral of the pipe network through pin connectors. The micro tube with sprinkler head unit is held erect by tying to a riser pipe, fixed near the plant to be irrigated.

 


The maximum allowable length of laterals in this system is 50m with about 20 sprinkler heads. An area of 1.0 ha can be irrigated in two splits by a 0.5 to 1.0 hp pumping unit with a pressure of 1.0 to 2.0kg/cm2. The units are capable of discharging 35 to 45 lph with an area of coverage upto 2.5m diameter. Coconut, Arecanut, banana, vegetables, vanilla, medicinal plants, lawns,

ornamental plants etc. have been found to respond well to this system of irrigation with maximum efficiency.

 

Low cost greenhouse for protected cultivation

Naturally ventilated greenhouse made of bamboo/arecanut/GI pipes and covered with UV stabilized polyethylene sheet are suitable for growing high value crops like cabbage, cauliflower, capsicum, tomato and cucumber round the year. Temperature and humidity build up inside the green house can be controlled by natural ventilation through insect proof nets (40-50 mesh) and by providing the required height to the structure. The optimum height of a greenhouse depends on floor area, ambient temperature, relative humidity, solar radiation and wind velocity of the locality.

 

 

 

 

 

Design of low cost greenhouse
An optimal design of a low cost greenhouse suitable for homesteads of Kerala is a gable shaped structure with a floor area of 75m2 provided with roof and side ventilation. The structure should have a ridge height of 4.35 m and gutter height of 2.5m. The roof slope should be around 300, effective side ventilation not less than 30 per cent and effective roof ventilation not less than 9 per cent the floor area of the greenhouse. The temperature inside the greenhouse increase with increase in floor area and decreases with increase in height of the greenhouse. Hence height of greenhouse has to be increased with increase in floor area.


The structure can be made of arecanut/GI pipes/bamboo poles. The bamboo/arecanut poles should be treated with chlorpyriphos (0. 2 per cent) to prevent termite attack. The structure should be covered with UV stabilized polyethylene sheet (200 micron) with at least 85 per cent light transmissibility. Side ventilators should be provided on either side of greenhouse at the floor level and roof ventilators should be provided at the top level throughout the length of the greenhouse as shown in figure. Ventilators should be provided with insect proof net. Crop yield under the naturally ventilated greenhouse is generally 3.5 times more than that of open field. Insect and other pest attack is limited to thrips and mites for which suitable control measures should be adopted. Off season production of vegetables is also possible in greenhouse which fetches a high market price to the farmer.

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Citation:
Kerala Agricultural University. 2011. Package of Practices Recommendations: Crops.

14th Edition. Kerala Agricultural University, Thrissur. 360p.