10 nutritional disorders of pepper

1. Pepper Production Guide for Asia and The Pacific 89
11.Nutritional Disorders of Pepper
airlyextensive work has been done in Malaysia on nutritional disorders in
pepper, including deficiencies of Nitrogen, Phosphorus, Potassium, Calcium,
Magnesium, Iron, Manganese and Boron. The problems resulting from cultivation
of pepper in acid soil conditions have also been examined. A summaryofthese
studies follows.
11.1Nitrogen Deficiency
Nitrogen Deficiency symptoms are generallycharacterised bypoor growth, with
pale and yellowish leaves (Fig. 59). At first, the lower leaves turn yellowish but
the upper canopy of affected plants tends to remain relativelygreen. In severe
cases, leaves of the entire plant show a characteristic yellow to orange -yellow
discolouration and the extreme end of the leaf tip becomes necrotic in some
instances. Leaf abscission is common in severely affected plants.
Fig. 59. Nitrogen Deficiency Symptoms, (a) and (b).
(a) (b)
Continued
F

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Fig. 59.(Continued)
(c) Leaves in upper canopy remain green
while lower leaves are chlorotic
(d) Leaves are chlorotic with yellow to orange
yellow colouration
Nitrogen deficiency maybe overcome by applying 40, 80 and 160 g N per plant in
the first, second and third year respectively, if pepper is planted in clayey soils on
gentle slopes. On coarse-textured soils and steep slopes, the rate should be
increased byas much as 50%. If urea is used to supplement complete fertilisers, it
must be buried in shallow trenches.
11.2.Phosphorus Deficiency
Clear symptoms of Phosphorus deficiency often rare in the field. In severe cases,
the most striking symptom is stunted growth of the plants. This effect is not so
much reduced terminal growth, but more of restricted lateral growth due to poor
secondary branching. Leaf blades of mature leaves become very dull looking, turn
bronze coloured, tend to be stiff and show necrosis at the tips in some instances,
before abscission occurs (Fig. 60).

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Application of 35g, 70g and 140g of P205
fertilizerper plant in the first, second and
third year respectively is recommended for
plantations on shale derived soils of clay to
clay loam texture. About 30% of the P205
should be in water-soluble form during the
immature stage of growth. Rock phosphate
is less efficient than water-soluble
phosphate and higher rates may be
required if the former is used. In sandy
soils, phosphate application in the third
andsubsequent years should be half that of
the recommendation for residual shale
soils. Application of phosphate as a foliar
nutrient is possible and spraying triple
superphosphate 1.0–2.0 % is recommended
in this regard, but this is more expensive.
11.3.Potassium Deficiency
Potassium deficiency symptoms can be seen on the distal end of affected mature
leaf blades becoming necrotic, brittle and grey in colour. Necrosis is usually
confined to the distal end, while the portion beyond the boundaryseparating
necrotic and live tissues displaysa ‘V’ shape band, which is yellow to reddish
brown. This band sometimes occurs without the ‘tip burn’ symptom (Fig.61).
Fig.61Potassium deficiency symptoms:
(a) Necrotic tips or ‘tip burn’
(b) ‘V’ band of yellow colour separating
necrotic tips and live tissues
Fig. 60. Phosphorus Deficiency
Symptom: Leaves are dull looking,
bronzy in colour and tend to be stiff.

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Application of 40g, 80g and 160–200 g K2O fertilizer per plant in the first, second
andthird year respectively is adequate for optimum performance on residual shale
soils. For coarse sandy soils, the rate should be increased to 270g K2O per plant
from the third year onwards.
11.4 Magnesium Deficiency
Magnesium deficiency symptoms first appear on older l eaves and progress to
younger leaves. In the early stage, chlorosis occurs in between main veins. This
usuallystarts from the central proximal half of the leaf. The chlorotic area
enlarges to the leaf tip and subsequently towards the leaf margin. A light dramatic
leaf fall is often induced, leaving the branches quite bare with only younger
unaffected leaves remaining on the plant (Fig.62).The area near the petiole often
staysgreen and gives an arrowhead effect of green tissue penetrating the
yellowing areas on the leaf.
Fig. 62 Magnesium deficiency symptoms:
(a) and (b) Dramatic leaf fall in severe case
leaving bare branches
and (c) Chlorosis in between
main veins of leaves
(a) (b) (c)
Apply 1.0 kg dolomite at planting and 0.5 kg per plant in subsequent years or
every alternate year. For acute deficiency,200 g kieserite per plant may be applied
to correct the disorder.

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11.5Calcium Deficiency
Visually, Calcium deficiency is first observed in fresh mature leaves as yellowing
or chlorosis which starts on either or both edges near to the petiole end or middle
part of the leaf blades. The marginal chlorosis advances inward, followed by
necrosis. The proximal and distal ends of the affected leaves are either green or
pale green. Tiny pinhead necrotic spots may appear scattered between the main
veins on the lower and upper surfaces of the leaves. Leaf abscission occurs before
the central portion of the leaf becomes necrotic. Die-back may occur at the
growing point. Leaves of the lower canopy are usuallymore severely affected
than those of upper canopy(Fig.63).
Fig.63 Calcium Deficiency symptoms:
(a) Early stage of Calcium Deficiency (b) Advanced stage-necrosis at the edges of leaves
Application of 1.0 kg dolomite per plant at planting and0.5 kg in subsequent
years can correct the deficiency.Deficient plants may take 2 –3 months for
complete recovery after applying dolomite. For acute deficiency, foliar spray
using 1.0% solution of calcium nitrate or 0.4% of anhydrous calcium chloride ha s
been recommended as for other crops, but is expensive and is not a long-term
solution.
11.6Iron Deficiency
Iron deficiency begins in the younger branches and is characterised by interveinal
chlorosis. The chlorosis occurs in between the main veins and smaller veins as
well, forming a fine reticulate pattern of green veins contrasting sharply with a
pale green or yellow background. The youngest leaves may be completelygreen
or even white. In acute deficiency,the internodal length of terminal shoots and
lateral branches is markedlyshortened and leaves tend to crowd together at the
upper end of the canopy. The berries of affected vines appear pale green to yellow
(Fig. 64, (a) and (b))

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Fig.64 Iron Deficiency symptoms:
(a) Symptoms are more severe on upper canopy
of affected vines,
(b) Healthy and iron deficient leaves and
berries.
When acute Iron Deficiency occurs, treatment is more difficult than for any other
nutrient deficiencies. Fortunately, treatment is often not necessary as the pl ants
normallyrecover as they grow older, probablydue to the development of more
extensive root systems, which enables a greater uptake of iron. Treatment is
attempted only in severe cases. Foliar application of FeSO4 salt at 0.5%
concentration is useful but several applications may be necessaryto provide
effective control. NB: Iron Deficiency mayoften be induced by natural
occurrence of excessive amounts of Calcium in the soil or from over liming a soil
with excessive amounts of lime or dolomite.
11.7.Manganese Deficiency
Manganese deficiencysymptoms are more severe in the upper canopyof affected
plants. Younger leaves turn chlorotic or yellowish white with onlythe main veins
remaining green. The older leaves produce a characteristic herringbone pattern
with green veins and the areas between the veins turn yellowish white. At a later
stage, small necrotic spots appear and grow in size in the pale areas. Manganese
andiron deficiencies can occur simultaneously as both are induced byover
liming. While the symptoms of young leaves in a manganese -deficient plant can
easily be confused with those of iron, the two deficiency symptoms are distinctly
different in the mature leaves. When deficiencies are prolonged and severe,
berries also show characteristic symptoms (Fig.65).

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Fig.65. Manganese Deficiency symptoms
a) b)
c) d)
Foliar sprays and soil applications of manganese sulphate have been used to
correct manganese deficiency.However, the former have generallybeen more
successful than the latter. One or more foliar sprays of 0.5% manganese sulphate
can usually correct the deficiency.
11.8.Boron Deficiency
Boron deficient plants are stunted with shortened internodes and reduced
branching. Young and recentlymature leaves show cha racteristic symptoms of
interveinal chlorosis at the distal and central portion. Young leaves are small and
distorted with pronounced puckering and necrotic lesions on the main veins
(Fig.66).

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Fig. 66 Boron deficiency symptoms:
(a) Young leaves are small and distorted with
pronounced puckering and necrotic lesions on
small veins,
(b) Stunted growth with shortened internodes and
reduced branching, interveinal chlorosis at
distal and central portion of leaves
Soil application of 10 g of sodium tetraborate per plant has been found to be
highlyeffective in correcting the deficiency and to increase leaf boron
concentrations to adequate levels.
11.9.‘Acid Soil’ Conditions
Necrotic spots develop along the main veins and also between the main veins in
the middle portion of the affected leaves. More than half of the distal portionof
mature leaves may become chlorotic. Symptoms in recentlymature leaves are
more severe than those of the younger and older leaves. In immature pepper,
growth is severely retarded. The root system of affected plants develops poorly,
having black and decayed roots, which are brittle. Leaves are shed prematurely
andthe yield of affected vines is poor. These symptoms are similar to those that
have been described as ‘Aluminium’ toxicity andmultiple deficiencies (Fig.67).
Application of 0.5 –1.0 kg dolomite per plant together with a foliar sprayof trace
elements can usuallycorrect the disorder. Recoveryis often slow, taking two or
more months. Application of water soluble kieserite (200 g/plant) in combination
with dolomite has been found to hasten recovery. The disorder maybe
complicated bynematode damage to the root system, particularly on sandy soils.

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Fig.67 ‘Symptoms of Acid’ Soil Condition:
(a) and (b) Necrotic spots along the main veins, and (c) Plant affected by ‘Acid Soil’
a) b) c)
11.10.Manganese Toxicity
Young leaves are normal while older leaves are affected. Dark brown to black
spots appear first at the leaf margin before extending towards the central portion
of the lamina. This eventually leads to a striking interveinal pigmentation.
Premature shedding of leaves and poor secondarybranching are observed in cases
of acute toxicity (Fig.68).
Fig. 68 Manganese Toxicity symptoms:
(a) Characteristic interveinal pigmentation mainly
on mature and older leaves in affected plants,
(b) Leaves showing increasing severity of
Manganese Toxicity from left to right
Application of 1.0 kg dolomite per plant, improving drainage of the planting site,
re-mounding with fresh soil and use of fertilisers with minimum manganese
content should overcome Manganese toxicity.