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IDEA-NEW
May, 2010
NOOR M NOORI
 Potatoes are not roots but it is under ground stems
called "tubers".
 Potato is one of the most important staple crops in
the world
 In the Eastern Region, potatoes are grown and sold
for both processing and fresh market
 Climate
 It is a temperate zone crop with a wide range of
seasonal adaptability.
 Young plants grow best at 24 Co, later growth is
favored at 18 Co.
 For Tuber production maximum at 20 Co, and at about
30 Co tuber production stops entirely.
 Exposing tubers to light, results in sunscald and the
production of solanine,
 There are more than 100 cultivars of potatoes.
 White-skinned and red-skinned cultivars are the
most common in Afghanistan.
 White skinned (Diamante, Kufri Chandramukhi
(KCM), Kufri Lauvkar,) and red skinned (Desire and
Cardinal).
 KCM and KL are short duration varieties with good
storage quality.
 The shape, appearance and yield of tubers
depend to texture and physical nature of the
soil.
 Potatoes can be grown on almost all types of
soils
 For best Yield on light soils, well drained
soils, rich in humus, is prefer
 Suitable pH 5 to 6.5.
 If potatoes are to be grown in clay soil, organic
matter should be added and plowed deeply
into the soil
 A basal application of 4-
6 T/jerib FYM should be
applied.
 A basal application of 3243 kg Urea, 21-34 kg DAP
and 20-30 kg Potassium
sulfate(K2SO4)/Jerib
should be incorporated
into the soil.
 If there is a micronutrient deficiency, a
mixture of micro
nutrient elements should
be applied.
 Potatoes are started from
"seed pieces" or small
tubers rather than from
true seed.
 The seed pieces are tubers
that have been cut into
42-56 g pieces.
 Each piece should have
from one to three “eyes”
(small sprouts).
 The pieces are planted 10
cm deep in raised seed
beds.
 The soil temperature
at planting should be
at least 7 Co but not
over 21 Co.
 Soils should be moist
but not excessively
wet.
 potatoes can be
covered with clear
plastic when the soil
temperature is low.
 Seed rate depends on tuber size; 160-200 Kg/Jerib is
generally recommended
 The distance between rows is typically 60-75
cm, and 20 to 30cm apart in the row.
 Spacing is determined by the desired size of
the tubers to be harvested and the cultivar
used.
 The physiological age of the seed pieces affects
the size and number of tubers produced.
 Avoid from planting of immature or not
properly stored or handled Seed potatoes.
 If seed is known to be 'old', spacing should be
increased
 Water management is probably the most
important factor determining yield and quality
of potatoes.
 Many Diseases and disorders are directly
related to the amount and the distribution of
water during the growing season.
 Potatoes need frequent irrigation;
 the first irrigation should be immediately after
planting,
 During the vegetative growth weekly base.
 After tuber formation, the frequency of water can be
decreased
 Watering is stopped a few days before harvest.
 Weeds should be removed as soon as they
appear.
 After the potato plants have emerged, organic
mulch can be applied.
 Pre-emergence herbicides can be applied just
after planting and soon after the field is
irrigated.
 The following products are pre-emergent
herbicides that can be used:
 Nitrofen (Toke-E-25, 25%) @ 0.2 kg a.i. /jerib,
 Alachlor (Lasso 50%) @ 400 g a.i.
 or Simazine (Tafazine 50%)@ 0.1 Kg a.i./jerib.
 Potatoes should be hilled or ridged to increase the
depth of the seed piece.
 Tuberization starts 30-35 days after planting,
 Since tubers only form it is important that
earthing-up be done at this time.
 Proper hilling is particularly important in clay soils
because tubers tend to rise to the surface
 Average potato yields in the Eastern Region were
3.5 T/jerib
 Now, with clean seed potatoes and improved
agricultural practices, yields are reaching 4-6
T/jerib.
 Insect Pests
 Potatoes are attacked by most of the insects which
infest closely related solanaceous plants.
 Since potatoes are grown for their edible tubers,
they must receive greater protection from pests.
 The adult and nymph of the
potato aphid are both solid pink,
green and pink mottled, or light
green with a dark stripe.
 They feed in colonies causing
discoloration.
 They often transmit virus
diseases such as PVY.
 Aphid populations are high
during the spring cropping
season (Feb-April) and less
during the fall season (SeptDec),
 Management of green peach aphid and potato
aphid involves an integrated program of reducing
overwintering populations.
 Controlling weeds in and around the field, and the
use of foliar sprays.
 Monitor to schedule spray treatments.
 The most common species
encountered are the black
cutworm and the variegated
cutworm.
 Cutworms may cut off the
stems of young plants during
stand establishment.
 Later in the season they feed
on foliage.
 Tubers that are exposed on the
soil, or by cracks, or are set very
shallow may be damaged.
 Monitor the field to detect cut plants and foliar
feeding early in the season.
 Later in the season, inspect plants for foliage
damage.
 Treatment is necessary where worms are
abundant and before the tubers are damaged.
 Two insecticides effective against cutworms
are:
 carbaryl (Sevin)
 methomyl (Lannate)
 It is attacks at two stages.
 In the early stages of plant growth.
 caterpillars mine or bore potato leaves
and shoots, causing leaf blotches and
killing the shoots.
 At harvest, moths lay their eggs on
the tuber.
 When the eggs hatch, the larvae
penetrate the tuber skin and make
galleries through the flesh, leaving their
excreta near the entrance holes.
 Do not leave harvested potatoes in the field
overnight.
 Store in sacks.
 Thoroughly clean storage places and spray with
1% Malathion or 0.6% Diazinon before storing
potatoes.
 Plant disease-free potato seed.
 Plant seed tubers at least 20 cm deep and cover
with about 25 cm fine, loose soil.
 Encourage specific Parasitoids, e.g.
Copidosoma hochleri and Apanteles
subandinus.
 Numerous potato diseases and disorders may be
caused by:
 bacteria fungi, viruses, phytoplasmas or may be
physiological in nature.
 While prevention of the many diseases affecting
potatoes vary widely depending upon the specific
disease.
 Some practices apply generally to all diseases,
These include the following:
 Use certified seed.
 Handle seed properly.
 Follow a regular and precise sanitation program.
 When applying fungicides, follow the instructions
on the label as well as the local authorities'
recommendations.
 Irrigate uniformly and adequately, but not
excessively.
 Control aphids, leafhoppers, and nematodes.
 Harvest and handle tubers kindly.
 Do not harvest when tuber temperatures are
below 7oCo or above 30Co.
 If storing, provide environment for wound
healing, followed by proper temperature,
humidity, and aeration.
 Warm cold tubers in storage before handling.
 Early blight is primarily a disease of stressed or
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senescing plants.
Symptoms appear first on the oldest leaves.
Affected leaves develop circular to angular dark brown
lesions 3–4 mm in diameter.
Concentric rings often form in lesions to produce
characteristic target-board effect. Severely infected
leaves turn yellow and drop.
Infected tubers show a brown, corky dry rot.
Between crops, the early blight fungus can overwinter
on potato residue in the field, in the soil, on tubers,
and on other solanaceous plants.
 Infection occurs when spores of the fungus come
in contact with susceptible leaves and sufficient
free moisture is present.
 Spore germination and infection are favored by
warm weather and wet conditions from dew, rain,
or sprinkler irrigation.
 Alternately, wet and dry periods with relatively
dry, windy conditions favor spore dispersal and
disease spread.
 Tubers can be infected as they are lifted through
the soil at harvest.
 If sufficient moisture is present, spores germinate
and infect the tubers
 It can be minimized by maintaining optimum
growing conditions,
 Including: proper fertilization- irrigation- and
management of other pests.
 Grow later maturing, longer season varieties.
 Fungicide application is justified only when the
disease is initiated early enough to cause
economic loss.
 Apply fungicides (Mancozeb, Maneb) as soon
as symptoms appear; continued protection
requires application at 7- to 10-day intervals.
 Late blight lesions can occur on all aboveground plant
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parts.
On leaves, lesions typically first appear as small pale to
dark green water-soaked spots that are irregular in
shape and surrounded by a zone of yellowish tissue.
Under favorable conditions, lesions expand rapidly and
become brown to purplish black as tissue is killed.
Under sufficient humidity, white sporulation of the
fungus can be observed at the periphery of lesions,
principally on the underside of leaves.
On stems and petioles, lesions are brown to black and
may also support sporulation of the fungus.
 Infected tubers develop a firm brown
decay that starts on the outside
 Inoculum of the pathogen can originate
from:
 seed tubers- cull piles- volunteers- closely
related weed hosts, and adjacent plantings of
affected potatoes or tomatoes.
 Late blight can develop and spread
rapidly if inoculums is present and
conditions are favorable.
 High humidity (above 90%) and average
temperatures in the range of 10°C to 25°C
favor the disease.
 PVY is one of the most prevalent and important viruses in
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potatoes.
Recently, strains of PVY which can cause necrosis (dead spots on
leaves and in tubers) have been discovered, creating more concern
about this widespread virus.
PVY is a Potato y virus, the type member of the largest group of
plant viruses.
It is transmitted by aphids in a nonresistant manner, by sticking to
aphid mouthparts (stylet).
The virus can be acquired from the infected plant within seconds,
and transmitted to a healthy plant just as fast.
PVY can also be transmitted mechanically by machinery, tools,
and damaging plants while walking through the field.
Aphids are by far the most efficient means of transmission.
Necrotic symptoms in tubers often increase after storage
 PVY can also be
transmitted mechanically
by machinery, tools, and
damaging plants while
walking through the
field.
 Aphids are by far the
most efficient means of
transmission.
 Necrotic symptoms in
tubers often increase after
storage
 Since PVY is a persistent virus and is
transmitted quickly by aphids, the use of
insecticides to control spread is generally not
effective.
 The best strategy to control PVY is to use seed
potatoes certified.
 Mineral oils can be used to reduce spread by
aphids, but must be re-applied at frequent
intervals to be effective.
 Rogue symptomatic plants of the Solanaceae
family
1-Harvesting
 Harvest preparedness
generally begins once
tubers have reached a
desirable size for the
cultivar or market.
1-Harvesting
 Immature potatoes are easily bruised and "skinning" leads
to shriveling or decay
 When the potato leaves start turning yellow and dry up, the
crop has entered the maturity phase.
 Vines need to be cut or killed, two to three weeks before
harvest
2-Grading
 Grading and
standardization of the
produce is essential as
it brings higher income
to farmers.
 For table use, tubers of
comparatively big size
are preferred.
 Cut or injured and green tubers are not accepted by
consumers.
 Oversized tubers are used for chips and medium size
potatoes fetch a higher price.
 The basic qualities is seed potatoes
 The size may vary from 2.5-3.75 cm in diameter.
3- Marketing
 Potato is a perishable and bulky
commodity with high water content
and thus requires large storage and
transport capacity.
 In cooler regions, storage is not a
problem.
 Marketing in warmer areas involves
handling and movement of potato
under unfavorable environmental
conditions.
4-Storage:
 Potato is a semi-perishable commodity.
 The cold storage has the capacity to store
tubers for an extended period.
 The tubers can be stored at 1-2.7 oC and 9095%RH.
 Farmers can store potatoes over the winter in a
dark room at a temperature between (3°C and
4°C) with high humidity.
 Check periodically for spoilage.
 Temperatures below 3°C cause internal damage
to the tubers
DERA MANANA