Z O H A I B U L H A S S A N

CITRUS

INTRODUCTION

• Origin: South East Asia

• Family: Rutaceae

• A prized fruit of Pakistan

• Ranks 1st among all fruits

• Shares 34% in total fruit production

• Shares one-third of total value of fruit’s exports

• Pakistan stands at the 9th position in mandarin production and

11th in orange production in the world.

( FAO, 2008)

PRODUCTION AND EXPORT OF CITRUS

Year Production

(000 tonnes)

Export

(000 tonnes)

2006-07 1472 343

2007-08 2294 411

2008-09 2132 466

2009-10 2203 533

Source: Ministry of Food and

Agriculture

Federal Bureau of Statistics

SHARE OF PROVINCES IN CITRUS PRODUCTION

Province Area

(000 hectares)

Production

(000 tonnes)

% share

Punjab 189.2 2219.3 96.72

Sindh 4.5 30.9 1.34

Khyber P.K 4.4 35.9 1.56

Balochistan 1.3 8.4 0.366

Total 199.4 2294.5

Source: Pakistan statistical year book, 2009

SOIL

• Deep sandy loam, loam and clay loam

• pH: 5.5-8.5

• Subsoil should be free from hard pan, sticky clay and water

logged conditions

• Poor soils with high pH are not suitable

• Soil requirements depend upon the type of rootstock used for

various species and varieties.

• Rough lemon is a good rootstock for dry, sandy loam soils of

Punjab, whereas sour orange performs better on the moist and

heavy soil of KPK.

TEMPERATURE

• Seed Germination:

15-30°C

• Vegetative Growth:

Optimum shoot growth: 25-31°C

Optimum root growth: 25-26 °C

FLOWERING

• Season:

February- March

• Lemon:

Throughout year, when growing in coastal regions with mild

winter

Spring, when growing in dry areas with hot summer and cold

winter

FRUIT SETTING

• Optimum Temperature for pollen viability:

15-20°C

• Pollen tube growth is temperature dependent

• High temperature causes poor fruit set

PLANTING SEASON

• Spring

February- March

• Autumn

September-October

TIME OF FERTILIZER APPLICATION

Nutrients and Doses Time of Application

FYM Dec-January

1/3 N + P + K (full dose) Before flowering (Feb)

1/3 N At pea stage

1/3 N In August

Micronutrients Foliar application in Feb

PLANTING GEOMETRY

• Square System

Planting distance: 22´ to 25´

64-90 plants/acre

• High Density Plantation

R×R: 20 ft

P×P: 15 ft

IRRIGATION

Over irrigation is more injurious than under irrigation in citrus

• Surface irrigation

1. Basin system

2. Modified basin system

3. Flood irrigation

• Sprinkler irrigation

• Drip irrigation

IRRIGATION SCHEDULE

Season/Month Irrigation Frequency

Spring (Feb-March) Once a month

Summer (April-July) Twice a month

Monsoon (August) Subject to rainfall

Autumn (Sept-Oct) No irrigation

Winter (Nov-Jan) Once a month

PRECAUTIONS IN APPLYING IRRIGATION

• Irrigation water may not be allowed to touch directly to the

stem of citrus tree

• Field and water channels should be precisely leveled

• Stop irrigation at flowering time

• Stop irrigation two weeks before harvesting

• Restrict irrigation in Oct-Nov

• Light irrigation during frosty nights

MAJOR DISEASES

• Phytophthora Gummosis or Foot rot

• Trunk Gummosis

• Damping off/ Root rot

• Wither tip

• Citrus Canker

• Citrus Greening

• Citrus Quick Decline

• Citrus Slow Decline

CITRUS CANKER

Citrus Canker (Xanthomonas compestris)• Bacterial disease

• Appear on leaves, branches, fruit

Symptoms

1. Small yellow spots are formed on upper epidermis, then on lower epidermis

2. Later, spots become bigger, brown, raised

3. Diseased area die and leaving hole

4. Spots also appear on twigs and fruit drop

• Example: K lime, Lemon, Grapefruit, Sweet lime, Sweet orange

Corrective measure

1. Selection of healthy nursery plants

2. Prune the affected part and spray with bacteriside (copper oxychloride)

3. Wind breakers should be used to stop the movement of pathogen due to wind.

CITRUS CANKER

Citrus Canker on fruit

Citrus Canker on leaves

CITRUS WITHERTIP

2- Citrus wither tip (Colletotricum gloeosporioids)

Fungal disease

a- Symptoms

1. All aerial part, leaves, braches and fruit are affected

2. Wilting from braches from top to bottom

3. Branches looks silvery grey leafless

4. Leaf fall is common

5. Pathogen kill the plant

b- Corrective measure

1. Improve growing conditions of the orchard

2. Spraying with cu based fungicides

CITRUS WITHERTIP

Citrus withertip

CITRUS GREENING

• Causal organism was first considered as virus. Later evidenced as mycoplasmal diseases and now classified as Ricketisa like organisms (RLO)

• Yellowing of veins and adjacent tissue

• Mottling of entire leaf

• Premature defoliation

• Die back of twigs and have shorter internodes

• Decay of feeder rootlets and lateral roots

• Decline and ultimate death of entire tree.

• Transmitted by grafting and Citrus psylla

• This disease is more severe on sweet oranges than on mandarin, acid lime and grapefruit.

Control:

• Application of tetracycline-antibiotic

• Control of Citrus psylla

CITRUS TRISTEZA VIRUS

• Vein clearing in lime

• Bronzing of leaves

• Stem pitting

• Twig and root die back

• Leaf drop

• Foliage wilt

• Sudden death

• Tree debilitation

• Reduced fruit size

• Necrosis of cambial tissue

CITRUS TRISTEZA VIRUS

Control:

• Aphid contol

• Use of tristeza tolerant rootstock

• Eradication of all infected trees

• Use of virus free buds employed for budding

CAUSES OF LOW CITRUS PRODUCTION

• High pH

• Low organic matter

• Saline soils

• Uncertain weather conditions during flowering (fog, frost, rains)

• Use of unfit tube well water

• Faulty intercropping

• Inadequate and imbalance fertilizer application

• Poor plant protection measures

• Non judicious irrigation

• Low grade nursery plants

• Mechanical injury to the plants during hoeing and ploughing

SUGGESTIONS

• Legislation in nursery industry should be made

• Govt. and private sector should be involved for raising the certified plants on commercial level

• To make the disease free true to type progeny plants, testing training should be extended from government institutions

• Only certified plants should be recommended for plantation and restrictions should be done for such nurseries those do not follow it

• Quarantine measures should be observed strictly

• Enhancement and conservation of existed Germplasm on more scientific basis