Some Medicinal Plants and their Uses.

Nepal, a Himalayan country, has diverse topographical, geo-ecological and climatic gradients that have distinct on distribution of various species of plants and animals as well as the human settlements in its small domain of 1,47,181 sq.km. Biological resources in Nepal represent a unique and enormous diversity of flora and fauna due to variations in topography, altitude and climate. Nepal is renowned for its richness in the natural flora and fauna distributed throughout its various altitude.

Non Timber forest Products are the valuable natural resource of our country. About 1590 genera and 231 families of flowering species of plants have been recorded in Nepal till 2006. About 72 plants species have been regarded as of commercial value while 18 species have been banned by Government of Nepal for commercial trade.

Non Timber forest Products are the main source of the income to rural people. Various medicinal and aromatic plants (MAPs) are being collected and used by various ethnic groups of Nepal. Since from the last decade various conservationists, various NGOs, foresters have shown keen interest to conserve NTFPs of Nepal along with conserving the forest.

      A) Bojho

It is a semi-aquatic perennial herb. It has creeping rhizomes. It is found in sub-tropical to temperate zone.

Nepali Name:  Bojho

English Name: sweet Flag

S.N: Acorus calamus

Family: Araceae

Habit: Perennial herb

Chemical constituents: Asarone, acorin, calamanone

Uses: 

Ø  Rhizome is usually used to treat cough, cold.

Ø  Root is chewed in case of the tooth ache and paste of root is also considered antiseptic to the wounds.

Ø  Calamus oil extracted have anti-spasmodic, anti-bacterial properties.

Ø  Powdered rhizome are used as insecticide to destroy lice, bugs, moths etc.

Ø  It also helps in promotion of memory and good voice.

 B)     Aloe vera

It is semi-wild perennial plant found in our country. Leaves are about 30-60 cm in length which are full of yellowish juice.

Nepali Name: Gheu kumara

Eng Name: Indian aloe

S.N: Aloe vera

Family: Liliaceae

Habit: Perennial herb

Chemical constituents: Aloesin, Barbaloin

Uses:

Ø  Leaves are used in the skin disease, bronchitis, eye disorders, jaundice, liver problems, fever etc.

Ø  Dye prepared from aloe gives purple color to silk and black color to the wool.

Ø  Flowers are used for anthelmentic purpose.

Ø  It is used in ayurvedic as well as in veterinary medicine for curing of various disorders and diseases..

 C)     Neem

Neem is a fast-growing tree that can reach a height of 15–20 metres (49–66 ft), rarely to 35–40 metres (115–131 ft). It is evergreen, but in severe drought it may shed most or nearly all of its leaves.

Nepali name: Neem

English name: Paradise tree

S.N: Azadirachta indica

Family: Meliaceae

Habit: Evergreen Tree

Chemical constituents: Azadirachtin, Nimbinin, salanin

 Uses:

Ø  The tender shoots and flowers of the neem tree are eaten as a vegetable .

Ø  Neem products are used by Ayurvedic practitioners as anthelmintic, antifungal, antidiabetic, antibacterial, antiviral, contraceptive and sedative.

Ø   Neem oil is also used for healthy hair, to improve liver function, detoxify the blood, and balance blood sugar levels.

Ø  Neem is a key ingredient in non-pesticidal management (NPM), providing a natural alternative to synthetic pesticides. Neem seeds are ground into a powder that is soaked overnight in water and sprayed onto the crop.

Ø  Young branches are good for cough, asthma, piles etc.

Transplantation of Rice

      Traditional method of rice transplantation being practised by some of students of                       Agriculture at Institute of Agriculture and Animal Science, Paklihawa Campus.

PHYSICAL METHOD OF PEST MANAGEMENT

Sometimes the most efficient way to kill insects is to stomp on them, literally or figuratively. Physical control method can be as simple as hand-picking the bagworms from a juniper bush, cutting tent caterpillars out of a shade tree, or using a fly swatter and window screens to keep your home free of flying insects. Physical Pest Control is a method of getting rid of insects and small rodents by removing, attacking, or setting up barriers that will prevent further destruction of one's plants. These methods are used primarily for crop growing, but some methods can be applied to homes as well.

Physical control method of insect pest comprises a number of technologies, some of which are based on active methods: Thermal shock (heat), electromagnetic radiation (microwaves, infra-red, radio-frequencies), mechanical shocks and pneumatic control (blowing or vacuuming tools). In the field, physical barriers represent the only passive technique available. This method aims to reduce the pest population by using devices that affect their physical environment.

Methods

1.  1.   Manipulation of Moisture:

Drying of grains up to less than 10% moisture before storage is a very good practice to prevent insect pest damage and draining of standing water is most effective method of destroying mosquitoes.

1.  2.    Barriers

Row covers are useful for keeping insects out of one’s plants, typically used for horticultural crops. They are made out of either plastic or polyester. They are made thin and light to allow plants to still absorb sunshine and water from the air.

Diatomaceous earth, made from fossilized and pulverized silica shells, can be used in order to damage the protective cuticle layer of insects that have them such as ants. When this layer is damaged, the insects become vulnerable to drying out. Unfortunately, the effectiveness of Diatomaceous earth decreases if it is wet. Therefore, it must be used often.^[2] This method was used back in the 1930s and 1940s when farmers would run dust over their fields. This would have the very same effect as diatomaceous earth.

3.      Traps

Fly paper or sticky boards are devices used in order to capture insects as they land upon the surface of the trap. They are covered in a substance that attracts insects, but are actually very sticky or poisonous. These traps are commonly used for flies or leafhoppers.^[3] Fly paper and sticky boards, for example, are often used in greenhouses to control whiteflies or leafhoppers.   Fruit and shade trees can be protected from various pests (e.g., plum curculio, gypsy moth, and codling moth) by tying a band of folded burlap around the trunk with its open side facing down.   As insects climb up the trunk, they are waylaid in the folds of burlap which can be treated with insecticide or inspected daily to collect the pests.

4.      Manipulation of Temperature:

a)      Cold storage: Placing produce inside of cold storage containers lengthens how long the produce lasts while also hindering the growth of insects inside of them. Cold storage of agricultural products prolongs their shelf life and retards the development of insect pests.  Most of insects become inactive around freezing point. Cold storage of fresh and dry fruits or vegetables is practiced to avoid fruit flies and potato tuber moth (PTM) damage.

b)      Heat treatment: Another method to use is to heat, as it will kill the insect larvae in certain types of produce. Heat treatments are sometimes used in place of fumigation to kill insect larvae in certain types of produce.   Mangoes, for example, are submersed in hot water baths (115°F for 68 minutes) to kill the eggs and larvae of fruit flies (Tephritidae) prior to export.

c)      Thermal shock: This approach is nonetheless is based on the premise that the commodity or the crop to be protected will be less sensitive than the target pest to an abrupt change in temperature. Research on thermal sensitivity and physiological reactions to short duration thermal stresses is central to the development of control methods based on thermal shocks.

d)     Fire: For farmers, fire has been a powerful technique used to destroy insect breeding grounds. It is used to burn the top of the soil in order to kill the insects that lie there. Unfortunately, this can present some drawbacks. Fire can make the soil much less effective or get rid of the insects that are beneficial to the plants. Also, there is no guarantee that it will actually solve the pest problems since there may be larvae below the surface of the soil. Fire may not kill healthy larva and pupa of pests that overwinter beneath the soil but may kill beneficial insects overwintering near the soil surface.

e)      Flame throwers: Flame throwers are employs against locust, hoppers etc they may also be used for burning weeds, scrub vegetations and localized sterilization of the soil. A flame thrower is essentially a pneumatic sprayer in which the lance is modified into a burner. The tank is field with kerosene, which on burning produces intense heat. The burner is so enclosed that the flame is thrown upward. By providing a hood it can also be thrown downward.  In the 1950's and 1960's enterprising farmers in the Midwest built tractor-driven flame throwers that used liquid propane (LP gas) to ignite and burn off the stubble from corn fields in the hope that a variety of soil dwelling pests would be killed by the heat.

5.      Tillage: Tillage was one of the first methods for controlling soil inhabiting pest. Exposure of overwintering phases of various insect pest to the sunlight after tillage helps in killing the insects before they reach to active stage. Also some larva such a white grubs are also exposed out to sun and birds.

6.      Manipulation of light:

a)      Light traps: This types of traps are useful for controlling the phototropic insects like moths, beetles etc. Insects are attracted to light and they get entered to the trap. Light traps are also called as “Bug Zappers”.

b)      Visible light can be used in 3 ways in controlling insects:

                                                        i.            By producing photo taxis: (+)^ve phototaxis= attracting effect

(-)^ve phototaxis = repelling effect

                                                      ii.            By inducing diapauses

                                                    iii.            By modifying oviposition

7.      Use of Radiant energy:

Several avenues have been explored for applying the different forms off electromagnetic radiation as a tool for controlling insects. Non-ionizing electro-magnetic radiation kills insects by raising their internal temperature. The utilization of radio, micro wave and infra red frequencies is based on a principle similar to that of thermal shock method except that, with applications involving electromagnetic radiation, the transfer of energy occurs without using a heat transfer fluid. The technologies that harness electromagnetic radiation are often too expensive for use in the field.

The radiant energy which have been used in insect control are:

                    i.            Radio Frequencies

                  ii.            Infra-red light                      

                iii.            UV-light and Visible light

                iv.            X-ray                    

                  v.            Gamma-ray                                  

Some other examples of Physical pest control:

Simple entrapment devices work quite well to control some types of insects. Fly paper and sticky boards, for example, are often used in greenhouses to control whiteflies or leafhoppers.   Fruit and shade trees can be protected from various pests (e.g., plum curculio, gypsy moth, and codling moth) by tying a band of folded burlap around the trunk with its open side facing down.   As insects climb up the trunk, they are waylaid in the folds of burlap which can be treated with insecticide or inspected daily to collect the pests. Ditches or moats with steep vertical walls are occasionally used as barriers to keep crawling insects (e.g., chinch bugs or white fringed beetles) from migrating out of one field and into another. Pitfall traps are dug at 3-5 meter intervals in the ditch and filled with kerosene or creosote to kill the pests.

References:

Chattopadhyay.S.B.1993.Principles and procedures of plant protection.3^rd edition.Oxford & IBH publishing co.pvt.ltd.New Delhi

Keller.S,Yubak Dhoj G.C.2013.Crop pest of Nepal and their management

Pedigo.L.P.2002.Entomology and pest management.4^th edition.Prentice hall of India pvt.ltd.New Delhi.India

Importance of Light Trap in IPM

    

Introduction:

     Integrated Pest Management (IPM) refers to the integration of various principles and  practices for the management of pests, so that it suppresses pest population below the economic injury level (EIL). IPM is an effective and environmentally sensitive approach to pest management that relies on a combination of common sense practices. IPM programs use current, comprehensive information on the life cycles of pest and their interaction with the environment. This information , in combination with available pest control methods, is used to manage pest damage by the most economical means, and with the least possible hazard to people, property, and the environment.

 

   Light traps are basically prepared on the principle that, most of the night flying insects are attracted towards the light source. Insects appear to be strongly attracted at light of 3650A. These are designed in such a way that when the insects are attracted and come close to the light source fitted in the apparatus they are fall in the trap fitted. Light traps can be used in various fields of pest (insect) infestations. They are used in vegetable fields, agronomy fields, fruits orchard, agro products storage , research fields, sometimes household, etc. These traps are successful in controlling certain species of moths, flies, some bugs, some flying beetles, etc.

                                              Figure 1: Generalised light trap                                                            

                                                                           

Classification of light traps:

           There are various light traps based on design and the light source used. Light sources range from simple oil lamps to different electric source.  Special light sources called black light have been developed and are particularly efficient because of the type of light they emit. They should be considered in situations  when other light sources (house, street light) are competing with the traps.

Design or Construction:

               Light trap contains basically two parts in it. One is the light source to attract insects and other the killing device to kill insect. Often there is a container with water placed under light source. It is better to add some soap in the water used for effective killing. Similarly sticky plates can also be used instead of water container. In some cases chemically treated nets can also be used to collect the insects trapped.

Advantages  of light trap:

·          Easily traps insect species

·          Cheaper in price and is hence affordable

·          Killing of insects favoured instead of chasing n repelling so controls permanently

·          Can be used in various places agri and non-agri purposes

·          Do not posses danger and residue problem

·          Gives immediate results

·          Requires low labour

·          Farmers can operate it it learnt once

·          Simple light traps can be made in home also using locally available light source

·          There is no problem of resistance

·          Safe to man, animal and natural enemies

·          Favours sustainable agriculture

·          Least or no chance of pollution

Disadvantages of light trap:

·          Requires few technical knowledge to operate

·          Highly efficient traps are quite costly

·          Not available to the all rural parts of the country

·          Is specific to particular nocturnal insects only

·          Beneficial insects are also killed along with the harmful insects

Proper functioning of light trap:

·          Once installed, insect light traps need little attention- just empty tray or replace the glue boards occasionally

·          ILT units function well as long as the bulb is lit

·          Traps with glue boards are better and more efficient than electrocutors

·          ILTs can be placed over or near food and food contact surfaces

·          Black light blue(BLB) bulbs or combinations of BLB and black light(BL) bulbs are more effective than BL lamps alone

·          Stunning circuitry improves the catch of glue board ILTs

·          Ultraviolet emissions from ILTs can effect human health

Light Trap In IPM:

      Light traps are the most effective and safe tools used for the IPM purpose. These never deviate the principles of IPM. These traps favour in the distraction towards chemical pesticides and insecticides. Worldwide pesticide problem was considered in  light trap invention. Ill effects due to various chemical pesticides are also avoided after the use of light traps. Pest can develop resistance against pesticides, which is completely avoided in case of IPM’s light trap technique. Light trap application favours in the sustainable agriculture practice, since it doesn't give any residual effects on the field.Light traps never harms the useful soil organisms, which is a part of ideal IPM.

Conclusions:

      Hence light trap has been found to be very essential part of IPM, which follows the IPM practice almost ideally. According to the requirement it can be set to either kill the pests or simply trap only. Trapped insects can also be used for study about the nature and their potentiality to be used under IPM practice. Finally Light Trap has been accepted to have significant importance in IPM.

Cultivation Practices of Potato in Nepal

                                                       

Introduction:

Potato, the tuber crop is the major field crop that rank first in terms of productivity and fourth in terms of production areas. It occupies more than 80% of the cultivated area in Europe and other areas and fulfills the food requirement by 50- 60 %.

Importance:

From the nutritional point of view, potato is the best source of food. It contains high amount of starch, protein (2%), fat (0.1%) and carbohydrate (19.4%). In comparison to cereal crops, starch and protein in potato has high digestibility. It has high biological value that is 98 in comparison to 82 in wheat and rice respectively.

Except Vit-A &Vit-E, it contains Vit-B₆ & Vit-C in adequate amount. Besides, it contains minerals (Fe, Ca, P, Mg, and S). According to British Association Certification, consumption of 125-150gm of potato daily fulfills the need of vitamins.

Besides, consumption of potato is advantageous to blood pressure, anemia, gastritis etc.

Potato is the native of South America and was cultivated by Incas. It was introduced into Europe by the early Spanish explorers during sixteenth century.

Botany:

Potato belongs to family Solanaceae. It is herbaceous annual and propagated by seeds, tubers (stolen). The stolen are slender, arising from buds, length and diameter varies with varieties. Eyes on the potato are buds and one or more develop into stem and leaves. Stem are green, leaves are compound with opposite leaflets. Height ranges from one to two feet depending upon variety. Roots are shallow extent up to two feet. Flowers are one inch in diameter, corolla white or purple. Fruit berry but commonly not developed. Seeds are similar to the seeds of mustard and heterozygous.

Climatic requirements:

Potato is cool season crop but is only moderately tolerant to frost. Temperature during the growing season has great influence in the yield. Generally, for germination 8^Oc is ideal. At very low temperature, growth and development is checked. Day temperature of 30-35⁰C and night temperature of 20-25⁰C is ideal for proper growth and for tuberation 18-20⁰C is ideal. High night temperature is hazardous & sometimes if temperature is above 29⁰C tubers are not formed.

Soil and soil preparation:

Potato can be grown on a wide variety of soil from lights and fairly heavy clay loam and on muck soil. But soil with good aeration drained light textured minerals soil reaction from pH 5-7 is ideal.

Soil ploughing and preparation depends upon, soil type, climate, ploughing instruments, virgin or cultivated land etc. but for effective growth and development, physical structure of soil as well as weeds, stubbles, sterilization of soil should be done. Soil preparation generally can be divided into two parts. First 20-25 cm deep ploughing followed by second ploughing is generally practised.  Furrow and ridges are made as per recommended spacing.

Planting:

A. Seed rate and spacing:

With line to line to line spacing of 70 cm and plant to plant spacing 23 cm and with 40 gm. per seed with 4 buds, 2.5 tons seed is required for one hectare in order to maintain ideal plant population and higher yield.

B. Planting season:

Area	Planting season	Harvesting season
Plain (< 300m)	Aswin- kartik	Falgun
	Mangsir	Chaitra
Hills (>300m)	Bhadra - mangsir	Mangsir- falgun
	Poush-falgun	Baisakh - jestha

Fertilizers requirements:

Potato is usually heavily fertilized since they have a high nutrient requirements and high gross value per area which makes heavily fertilization. 30 tons of production removes 150 kg N, 60 kg P & 250 kg K, 90 kg CaO, 30 kg MgO.

Fertilizers application depends upon soil type, soil fertility, temperature, crop rotation, irrigation facilities. In general, 20-30 tons FYM, 150-200 kg N, 75-100 kg P, 150-175kg K is recommended.

Time of application:

Full dose of FYM, phosphorous, potassium and half dose of nitrogen at the time of field preparation and remaining half dose of nitrogen at earthing time by side line or point dressing.

Irrigation:

Pre sowing or pre emergence irrigation than after second irrigation after 30 days and next irrigation as per necessary.

Moisture availability should be adequate for proper growth and development of tuber and sprouting. Low moisture content results for tuberation, poor quality tuber and poor germination. Production of 1 kg of potato required 300-636kg of water and more.

Inter- cultural practices:

A. Weed managements:

Weed control practice is prime necessary in order to reduce loss due to weeds as weeds compete with the potato. At early stage of growth when the is small, weed problem severe, so, 1 hand weeding and hoeing when plant is 10-15 cm. then small growing weeds are controlled at the time of earthing.  Then after the plant can cover the weeds and disorganized the effects of weeds. If necessary, next hand weeding can be done.

Chemically, weeds can be control by the application of lasso @ 3 ltr/hac as pre- emergence or post-emergence or a pre- emergence spray of a dinitro compound + diesel oil in the water or sodiumpentochloropenate +diesel oil in water.

B. Earthing:

In order to protect growing tubers from radiation, hot, insect, late blight etc. Plant is covered with soil to some extent depending upon the depth of sowing or planting. If sown to great depth, size of small ridge is enough. Earthing is done when plant is 15-20cm tall at proper moisture level.

Harvesting:

When the plants are turned yellowish & drying, potato is harvested. Before 7-10 days of harvesting, plants are topped at its base or stopped irrigating before 10-15 days of harvesting which helps to mature the coat of potato.  Potato is harvested with the help of khurpi by destroying the ridges side by side.

Yield:

With the modern improved cultivation practices, 350-500 quintals of potatoes can be produced.

Grading:

Rotted & damaged tubers are assorted. According to the market necessity, they are graded. Grading is done according to their size, like big, medium & small. For grading iron mesh wire with varying size are used.

Post-harvest management:

After harvesting & grading, tubers are surface dried & kept in shade in heaps for 10-15 days. If the produce is to be marketed early to take benefit of high market price, it is advisable to harvest potato in stage because of high perishable nature of immature tubers.

Various points for seed plot technique of potato under plains:

In order to obtain healthy & high yielding seeds, we have to focus on the following points;

·        Use of healthy & disease free seeds.

·        Timely sowing (end of Oct.).

·        Use of 3/4^th dose of nitrogen.

·        Use of the whole tuber seeds.

·        Use of insecticides (Rogar).

Critical limit- 20 aphids per 100 compound leaves.

·        Hand cutting (3^rd week of January).

·        2 weeks onward of hand cutting harvesting is to be done.

·        Sorting & tuber treatment (3% Boric acid for 30mins.).

·        Bagging & storage.

True potato seeds (TPS):

The non-availability of good quality seed tuber, high seed cost, virus infiltration in seed tubers causing degeneration of seed stocks & problem of long distance transport of seeds from seed producing areas have led to the development of TPS technology of crop production.

Following considerations have to be taken for TPS technology:

·        TPS has to be sown in nursery beds to produce seedlings. The best substrate for nursery beds is a mixture of 1:1 FYM & soil.

·        TPS germinates well when night temperature drop to about 20^oC in the plains & shade is provided over nursery bed areas during day time. In plains the best sowing time is October.

·        The seedlings raised in nursery can either be transplanted in field to produce a ware/seed crop alternatively allowed to tuberize in the nursery beds produce small seedling tubers which can be used for field planting next year.

·        The method of raising the crop using small seedlings tubers produce in nursery bed is successful in all the potato growing regions of the country.

·        The raised seedlings for planting in 1ha, about 100gm TPS is required to be thinly sown in 50sq. meter nursery bed areas at 10cm, into row distance seedlings will be ready for transplanting in field in about 20-25 days of germination.

·        For producing seedlings tubers for planting 1ha in the following crop season, 40gm TPS is required to be sown in the nursery at 10cm X 10cm inter & intra row spacing. The haulms may be cut on the dates recommended for the seed crop in the area.

·        The ware crop from seedling tubers can be raised following the standard agronomic practices of the area, keeping in view that smaller tubers are to be planted at closer spacing. The suitable inter & intra row spacing are 60cm X 20cm for 20-30mm, 60cm X 15cm for 20-25mm, 60cm X 10cm for 15-20mm & 60cm X 5cm for 15mm sized tubers.

·        The field produce can be used as seed for at least for2 seasons in potatoes seed producing areas & for 1 season in other areas.

TPS varieties (white varieties):

·        HPS-1/13

·        TPS/C-3

·        92-PT-27

Varieties recommended in Nepal:

1.    KufriJyoti:

·        Medium (110-120 days in hills, 100-110 days in mid hills).

·        Resistant to late blight, size large oval shaped, skin white smooth.

·        6 weeks dormancy period.

·        Yield 20-25tons/ha

2.    KufriSinduri:

·        Late (110-130 days), size medium, round shape, skin red smooth

·        Dormancy period 8 weeks or more.

·        Yield 25-30 tons/ha, moderately resistant to early blight.

3.    Dejire;

·        Medium sized, shape oval, smooth, red color skin.

·        Early (70-90 days), susceptible to blight.

4.    JanakDev:

·        Medium to large size, color red.

·        Medium (100-120 days) can be grown in terai mid hill and high hill.

·        Dormancy period 6-8 weeks, yield 23 tons.

   5. khumal seto-1:

·        Round shape, both small and large size, skin colour white.

·        Medium (100-120days), yield 25.1 ton/ha.

·        Dormancy period 6-8 days, resistant to viral diseases. 

  6. khumal rato-2:

·        Medium size, round shape, smooth skin, light red colour.

·        Yield 20-25 ton/ha, resistant to Y-virus.

·        Medium variety (100-120 days).

 7. Kufribahar:

 Medium maturity, size large, shape round, oval, skin white, susceptible to all major diseases.

Following are some other commercial varieties of potato recommended in Nepal

8. Kufrilalima

9. Kufrichandramukhi

10. Local red round

11. Magnum bonum

12Up-to-date

13. T-0012

14. NPI-106

15. Cardinal

Recommended varieties in different ecological zones of Nepal:

Varieties	Recommended zones
1. Cardinal	Terai, valley and mid hills
2. NPI-106	Mid and high hills
3. NPIT/0012	Mid and high hills
4. Kufribadhshah	Terai
5. Sarkariseto	Eastern hills
6. Tharu local	Mid and western terai
7. Jumli local	Western terai
8. Kathmandu local	Kathmandu valley
9. CFM-69.1	Mid and high hills
10. I-1124	Mid and high hills

Diseases:

Fungal diseases:

1. 1.   Late blight:

C.O. Phytopthora infestans

Symptoms:

·        Appearance of water soaked areas which enlarges rapidly and then turn brown or black as the leaf dies.

·        White downy mildew sometimes on the lower side of the leaves.

·        The late blight produces a dry rot.

Control:

·        Spray Bordeaux mixture at interval of 6-10 days.

·        Spray Diathene M-45

·        Use resistant varieties.

1. 2. Early blight:

C.O.Altrnaria solani

Symptoms:

Initially brown spots and increase in size with concentric rings.

Control:

Spray Diathane M-45 (0.2%)

1. 3   Stem canker:

C.O. Cerospora solani-tuberosis

Symptoms:

Similar to early blight but white appearance in the spot.

Control:

Spray Diathane M-45 (0.2%)

1. 4   Dry rot:

C.O. Fusarium caerulium

Symptoms:

Fungal growth in eyes, lenticels and wounds.

Control:

Prevent the injury and use of free seeds.

Bacterial diseases:

1 1)    C.O. Pseudomonas solanacearum

Symptoms:

·        Brown ring is observed in the stem.

·        Black appearance of the potato eye.

Control:

Crop rotation in 2-3 years and proper irrigation.\

2 2)    Soft rot:

C.O. Erwinia cartovora

Symptoms:

Bacteria enter into the tubers through the lenticels.

Control:

·        Proper irrigation.

·        Storage after treatment of drugs with exposure to air for an hour.

3 3)    Common scab:

C.O. Streptomyces scabies

Symptoms:

Corky spots vary in size and number from a few small dots to large lesions.

Control:

Disinfect tubers with Agallol-6 or Mercuric fungicides.

Viral diseases:

1.       Leaf roll: leaf rolls and thickened.

    II.              Mild mosaic: light coloration in leaf vein and mixed with dark green.

   III.        Severe mosaic: stunted growth, uneven appearance of stem and scarp appearance on the leaf.

Insects/pests:

    1)   Cut worms: spray Dursban-20 EC or apply phorate in soil.

    2)   Caterpillar: spray Thiodan or BHC (10%)

c  3)  Aphid: spray rogar or malathion.

    4) Jassids: Spray metasystox (0.8%).

Physiological Disorders:

a   1)    Internal brown spots:

It is characterized by irregular, dry brown spots scattered through the flesh of tuber due to irregular irrigation.

     2)   Black heart:

When potato are stored high temperature of 35-40^oC they develop black heart in which inner tissues break down and become black which may be due to lack of oxygen, accumulation of CO₂ and high temperature.

c   3)    Hollow heart:

It is characterized by irregular cavity in the center of tuber. Surrounding the cavity, there is no decay or discoloration. It is produced in large sized tuber variety which can be overcome by closure spacing and avoiding excessive use of fertilizers.

    4)   Chilling injury:

It is due to storage of tubers for long time at temperature of about 0⁰C. This result in discolor blotches in the flesh of tubers which vary from light reddish brown to dark brown.