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1. Physiological disorder in tropical
fruit crops

2. 1. Fruit Drop
Very serious
At all stages-pinhead drop, post setting drop, May-
month drop
Reasons
 Embryo abortion, climatic factors, water relation,
lack of nutrition, attack of disease and pest and
hormonal imbalances
Control
₠ NAA – 20 ppm, 2 sprays
₠ Adequate moisture
Production Problems

3. 2. Irregular / Alternate / Biennial bearing
mango trees to bear a heavy crop in one year and very
little or no crop in the succeeding year .
Reason
Genetical, physiological, environmental and nutritional factors
Control:
• Regular bearing varieties / hybrids
• Deblossoming is recommended to reduce the crop load
• Soil application of Paclobutrazol (PP333 ) or Cultar @ 4
g/tree in the month of September resulted in early
flowering with higher fruit set and yield

4. 3. Malformation
1.Vegetative
2.Floral malformation
Vegetative - develop abnormally as compact rosette-like shootlets or
many such shoots may arise to form a bunch

5. Floral malformation
• Affected panicle, appears like a compact mass,
• more green and robust
Remedies : application of 200ppm NAA during the
first week of October

7. 4. Black Tip
 Yellowing tissues at the distal end of the fruit, become
brown and finally black
Reason
Coal fumes of brick kilns - sulphur dioxide, ethylene and
carbon monoxide
Control
• Orchards 1.5km to the east and west and 0.75km to the
north and south away from the kilns
• Height of chimney of brick kiln -18-20m
₡ Borax 0.6% spray or caustic soda 0.8% at flower
initiation stage
₡ Soil application CaCl2 & Borax

8. 5. Spongy Tissue
“A non edible sour patch developed in the mesocarp
Reason
₪ Low calcium
₪ Convective heat
Control
₣ Sod culture, green vegetation
₣ Mulching, leguminous cover crop, CaCl2 spray

9.  Fruitlets in clusters at the tip of panicles appear as bunchy tip
Fruitlets are dark green in colour and having deeper curve in sinus beak region
 Cease to grow beyond pea or marble stage and drop down
Inadequate population of pollinators in the orchards
 Spraying of NAA @ 200-300 ppm during October-November is beneficial

10. Leaf Scorch
 Scorching from the leaf margin towards midrib and from
tip towards petiole and on the leaf
 The excess of chloride in soil or irrigation water makes potassium
 unavailable which leads to the deficiency of potash in the leaf.
 Spray of potassium sulphate 5% on young leaves

11. Choke throat
 The distal part of the inflorescence comes out side of the plant.

12. ill filled fruits with a prominent central core having many
underdeveloped seedy structures making the fruit inedible.
Kottaivazhai
Application of 2,4- D 25ppm and GA 100ppm after the opening of last hand

13.  Neer Vazhai (Neer = water and vazhai = banana) is a malady of unknown
etiology.
 The fruits ooze out watery fluid when cut.
 It affects Nendran banana in Tamil Nadu.
 Infested plants show poor plant growth, delayed shooting, lanky bunch with few
hands and immature unfilled fingers.
Neer Vazhai

14. Potassium deficiency
 Yellowing of older leaf, grow slowly , poor fruit filling

15. Hard Lumps in banana
It is characterized by pinkish brown, firm pulp than the usual soft pulp
occurs in cv.Rasthali, tastes like immature or unripe fruits
Spraying the bunches -2,4 D at 1000 ppm or
dipping the cut end of peduncle of the bunches
for a period of 5 minutes

16. Malformed fruits
-Boron deficiency,
-Spraying of boric acid 0.1% at 3 months interval
from sixth month after planting

17. Frog skin” or “Skin Freckles
 Dark brown spots on the skin of the fruit
Remedies
Wrapping young fruits in white paper bags significantly reduced freckle incidence.

18. Citrus – Fruit Drop
 Immediately after fruitset at marble stage
 Onset of hot summer weather during May-June
 Premature drop
Application of 2,4-D 10ppm
two times – I week of May and I week of September

19. • Granulation
– Juice sacs become hard, dry, assume grey color and
become enlarged
– insipid taste and assume a granular texture
– Common in Sathgudi, Mosambi, Jaffa and Malta Blood red
– Vigorous rootstocks like rough lemon, Late maturity and
persistent cold weather
– Avoid excess irrigation and reduce the amount and
frequency
Spraying of GA 15 ppm followed by NAA 300 ppm in October and November

20. Citrus decline
 Continuous dying of the twigs
 Retarded growth and unproductive.
 The improper and inadequate nutrition as well as low organic matter, excess of
Fe, higher uptake of Mn and nonavailability of micronutrients like Zn, Cu, Mg and
boron aggravate tree decline
 Excessive irrigation, water stagnation and use of saline water also lead to citrus
decline.
 Proper manuring and use of resistant rootstocks
and maintains the growth and vigour of the plants.

21. Degreening
 Fruit attain full maturity, their colour remains green
 Spraying of Ethrel @ 2000 to 4000 ppm at pre harvest stage

22. • Sun scald/sun burn
– Problem during summer harvest of fruits
– Yellow patches over the fruits in areas exposed to
sun
– The patch gradually turn brown and hard
– Inner portion desiccated and discoloured
– Fruits malformed and have low juice content
– Fruits drop off and leaves turn brown

23. Fruit cracking or splitting
 Splitting may be radial (Longitudinal) or transverse, radial being more common.

24. Shot berries

26. • Uneven ripening
– Green berries in ripe bunch
– Varietal problem
– Inadequate leaf area, non-availability of reserves to
developing bunch
– Ethephon 250 ppm – at colourbreak stage
• Postharvest berry drop
– Weak pedicel attachment to berries
– NAA- 50 ppm – 1 week before harvesting

27. • Flower-bud and flower drop
– After full panicle expansion – flower buds drop
– Reason not known
– Stem girdling 10 days prior to full bloom
• Pink berry formation
– Common in Thompson seedless and Tas-A-ganesh
– Pink blush on few ripe berries before harvesting
– Berries become soft and watery
– Reduced shelf life
– Ascorbic acid 0.2% and Sodium diethyl dithiocarbamate
0.25% at 15 days interval after berry softening

30. Flat limb - FASCIATION (Botryodiplodia theobromae)
• First reported in Maharashtra and Gujarat
• Affected branches become flat and twisted with rough
marking
• Leaves - thin, small, yellow and clustered
•Flowers infertile and fail to set fruits
Control - Prune and destroy affected branches

31. Loranthus

32. Guava Bronzing
 Affected plants show purple to red specks scattered all over the leaves.
 Fruits - brown coloured patterns on the skin and reduced yield
Remedies
 Foliar application 0.5 % diammonium phosphate and zinc sulphatein
combination at weekly intervals for two months reduced the bronzing in guava
Pre-fowering spray with 0.4 % boric acid and 0.3 % zinc sulphate increase
the yield and fruit size
Spraying of copper sulphate at 0.2 to 0.4 %