2. Fruit drop
Fruit drop is the detachment or separation of a fruit from a
branch of a tree or a plant, caused by the formation of a
separation of layer of cells on the fruit stalk due to a series of
physiological and biochemical events.
The substances bonding the cells of the separation layer
dissolves and the cells separate from each other. Middle lamella
became soft by the action of hydrolysing enzymes (pectin
At this stage of the process, the fruit is attached to the plant only
by a vascular bundle.
(alphonso), citrus, avocado, peach, figs etc and also observed in
apple and pear.
3. Causes of fruit
1. Conditions of pollination
2. Seed content of fruits
3. Competition between the
organs of plants
Competition between the vegetative
and generative organs
Competition between the
4. Physiological and hormonal
1. Climatic conditions &
Irrigation, water supply
3. Biotic factors
4. Internal factors
5. Conditions of pollination and fertilization
Ortega et al. (2004)- More fruit drop- if the pollination occur - 4th or
6th day after the emasculation of flower buds Ex- Aonla
In Sweet cherries, more fruit drop due to embryo abortion or
competition between the seed and the pericarp for resources (Bargioni,
In the variety ’Napoleon’ of cherry, preharvest fruit drop is observed
caused by the degeneration of the endosperm (Guerro-Pietro, 1984).
According to Tylus (1975), preharvest fruit drop is observed only in
varieties characterized by high rates of fruit set.
Excess fruit drop due to insufficient resources(Wellington et al ,1975).
6. Seed content of fruits
The most important precondition of the fruit to be maintained on
the tree is its seed content.
The seed content of fruits – as Auxin factories – are important
factors of maintaining fruits on the tree.
Fruits with less seeds are more susceptible to environmental
adversities, i.e. water stress, poor nutrition, etc. and are prone to
drop fruits (Webber,1923; Stosser, 2002).
Teskey & Shoemaker (1972) claimed that in apple, fruits
containing less than 3 seeds are shed first when fruit set was
Murneek (1987) too estimated the fruit drop of pears containing
less than 3 seeds per fruit.
7. Competition between the vegetative and generative
The number of fruits on the tree- depends on organic nutrients
furnished by the leaves nearby, whereas the rest is prone to be dropped
Brunner (1982), refers that the balance expressed by the ratio of
leaves and fruits.
In apple, 1–4 leaves for one fruit set, 10–15 leaves around June drop
and 40 leaves at the end of fruit development needed.
The weak development of the leaf area, induces fruit drop.
Young leaves delay the abscission of ripe fruits, whereas mature leaves
promote the abscission of fruits by stimulating the transport of ABA
8. Competition between the generative organs
The flower or fruit set, started growing earlier becomes dominant
than flower or fruits lagging relatively behind (Bubán, 2002). This
type of dominance is called primogenous (Bangerth, 1990).
The fruits which developed at distal end and lateral
branches, are more prone to fruit drop.
9. Physiological and hormonal bases
The abscission of young fruits depend on auxin as a correlative
dominance signal (Bangerth, 1990).
The endosperm of the ovule (seed primordial) is the source of
Unfertilized flowers lack in seeds so no growth substances
therefore they abscise soon (Friedrich, 2000).
According to Bubán (2003), the premature abscission of fruits is
determined by the relative concentrations of IAA and ABA.
10. The role of ABA in abscission has been proved in apple (Vernieri
et al., 1992), litchi (Yuan & Huang, 1988), citrus (Talon et al.,
1990b; Sagee & Erner, 1991; Goren, 1993; Gomez-Cadenas et al.,
2000) as well as in cotton (Guinn & Brummett, 1988).
Tari (2004b) proves the presence of jasmonic acid in abscission.
According to Tari (2004), maintains that the principal regulator of
abscission is ethylene, which is suppressed essentially by IAA.
11. External factors
12. Climatic conditions
Premature fruit drop is caused by high probability adverse
environmental conditions (Soltész, 1997).
Eggert (1960) referred the temperature(more than 28 c) as an
important factor responsible for the June drop of apple.
Surányi & Molnár (1981) refer also to the effect of temperature in
the fruit drop of apricot.
Coit & Hodgson (1919), concluded that high temperature and low
relative humidity caused in ’Navel’ orange a high degree of June
Haas (1926) recognized the water loss is an immediate cause of
13. Tomato fruit drop - <55 F temperature
High temperature (39-42 C) during stage of fruit set development
causes fruit drop. Ex- cashew nut
Preharvest fruit drop is aggravated by wind and weather adversity
(Nagy & Kovács, 2005). The pear variety ‘Hardy’ is especially
susceptible to wind (Göndörné, 2000).
Fruit drop of sweet cherry is more when cool and rainy weather is
followed suddenly by a dry and hot period.
Poor light conditions (e.g. shading) increase the incidence of fruit
drop in sweet cherry (Patten & Proebsting, 1986)
14. Phytotechnical interventions
Fruit thinning--- Soltész, (1997) refers that right timing of fruit
thinning in apple is important to reduce fruit drop. Ex- grapes
Irrigation, water supply--- restricted amounts of water is one of
the causes of fruit drop.
Heavy fruit drop may be caused also by excessive watering, which
made split fruits near maturity (Anonymus, 2005).
Nutrition-- An overload of fruits is often considered to induce drop
of young fruit because of the relative scarcity of nutrients
Tarita et al. (1979) stated the same in relation of sour cherry, which
could be saved from the first fruit drop by nitrogen.
15. According to Feucht (1970), on the other hand, excessive
nitrogen, more than 21% content in the leaves, causes a heavy
drop of fruits in blueberry.
Potassium, boron and calcium also play a major role in fruit drop.
Harvest:-- In the regulation of fruit drop, the timing of harvest
fulfils an important role.
The technology of harvest is an important moment too especially
in mechanical harvest.
16. Biotic factors
Symptoms of senescence also in healthy tissues, which are often
leading to fruit drop.
Premature fruit drop caused by scab (Venturia carpophyla) and
drought condition in apricot and peach is particularly dangerous.
Fruit drop of walnuts may be induced by Gnomonia sp.
Gooseberry, blueberry and blackberry are haunted by grey mould
(Botrytis) causing fruit drop.
In peach, Taphrina is registered as most important, in all stone fruits
the scab and in small fruits the grey mould is threatening.
The fungus causing fruit rot (Monilinia fructicola) is generally
recognized as initiating fruit drop. Ex- Apple
17. The leaf-curl disease of peach (Taphrina deformans) fruit drop may
occur at vigorous infection.
Fruit rot (Phytopthora sp.)- fruit drop in nutmeg.
Animal pests belong to the most frequently met agents causing
fruit drop (Singh et al., 2005).
Pollu beetle causes the berry drop in black pepper.
The grub of the red backed proboscide weevil
penetrate into the fruit and feed on the seeds
affected fruits stop growing, shrivel and dropped
EX- Apple, Pear, Quince, Plum, Almond
18. Proboscid weevil of the hazel (Balaninus nucum) and of the oak
brings up their grub within the hard shell of the nut
They drill a hole of cc. 2 mm diameter and feed on the kernel
weevil is the precursor of the fungus (Monilia fructigena)
The oriental fruit moth (Grapholitha molesta) is mainly found on
peach, apricot causing fruit drop.
The apple moth (Cydia pomonella) is responsible for fruit drop (30–
40%). Ex- Apple, pear, quince and walnut (Garai, 2005).
19. In May and early June, the Plum moth (Grapholitha funebrana)
attacks the green fruits of minor size
small holes and gum extrusions appear
Apple wasp (Hoplocampa testudinea)
larvae drill a hole into the fruitlet
reddish brown or black juice appears entrance of hole
white larvae are identified within them
Fruit drop (72.6%)
20. Codling Moth(apple moth)
21. Remedies of fruits drop
The crossing between pant shivani and
pant sujata gave reduced fruit drop (59.86%).
Hand pollination of nonpareil almond with pollen from angle,
resulted in reduced fruit drop.
In musket and ruby red, the fruit drop was lowest under natural
In Bangalore purple and Thompson seedless, self hand pollinated
results in lowest fruit drop.
kagzi Bhadri recorded maximum fruit set and reduced
fruits drop followed by kagzi kalan pummelo
23. Plant growth regulators
Fruit drop occurs when auxin level goes down, hence we can check the
fruit drop by the application of auxin exogenously.
NAA (20 ppm) most effective in reducing fruits drop in 16- year old Ber
Spray of GA3 (60 ppm) recorded the lowest fruit drop (75%) and highest
fruit set (16.6%) in Ber cv. Umran.
Application of 2,4-D (10 ppm) and (20 ppm) resulted in minimum
percentage of fruit drop in Kinnow mandarin and Nagpur mandarin
20 ppm of NAA- mango – min fruit drop
Fruitone (NAA), Re Tain, AVG(aminoethoxyvinylglycine) & Harvista act
as ethylene inhibitor.
24. Mineral nutrients(INM)
Foliar application of borax(0.1%)- in June July- reduced fruit
drop – Bael cv kagzi
Spraying with 1.5% potassium sulfate and 1.5% potassium
nitrate - lowest fruits drop(75.22%) - Ber cv Umran.
Boron 0.4% + 10 ppm of 2,4-D application- reduced fruit
drop- in litchi
Application of 0.75% zinc sulfate – less drop – in sweet
orange cv Jaffa
26. IDM and IPM
Prune the plants after harvesting to minimize pest and disease
Dropped fruits should not be left in the field as they acts as carrier
for the disease.
Bait containing Malathion or Fenthion 0.05%+1% crude suger
should be hanged two months before fruit ripening.
carbaryl@2g/l of water should be sprayed twice at 12 days
interval after fruit set.
Avoid unfavorable environmental conditions.
27. Case studies
28. Moderate plant water stress reduces fruit drop of “Rojo Brillante”
persimmon (Diospyros kaki) in a Mediterranean climate
E. Badal, T.A. Abd El-Mageed, I. Buesa, D. Guerra, L. Bonet, D.S. Intrigliolo
Moncada, Valencia, Spain
to establish and quantify the effects of plant water stress on fruit drop
of the ‘Rojo Brillante’ persimmon cultivar.
A field experiment was conducted during three consecutive seasons
with mature trees. Three irrigation regimes were tested: Control,
always well watered; and two deficit irrigation (DI) treatments.
(1) Control, where irrigation was applied in order to minimize soil
(2) DIearly, where deficit irrigation (50% of Control irrigation regime) mid
May to mid July.
(3) DIlate where 50% of the Control regime was applied from mid July to
the end of August
Moderate plant water stress (stem >−1.3 MPa) occurring early
in the summer (mid-May to end of June, coinciding with the
fruit drop waves) decreases fruit drop.
Early season water stress had a greater effect on reducing fruit
abscission during the second wave of fruit drop.
In semi-arid climates, this knowledge can be used for
increasing ‘Rojo Brillante’ persimmon fruit set by restricting
irrigation applications during late spring.
Water stress applied later, at the end of the fruit drop period,
had less of an effect on reducing fruit drop.
30. Response of chilli (Capsicum annum L.) to plant
Chaudhary, B. R. 2004. [Student I. D. No. R-2002-HRT-06-M, Advisor: M. D.
Sharma, Members: S. M. Shakya and D. M. Gautam].
Flower and fruit drops in chilli are the major problems.
A field experiment was conducted to identify most effective plant
growth regulator in improving fruit set and reduce fruit drop.
The experiment was carried out in a split plot design, keeping
varieties (Jwala and Suryamukhi) in main plots, and growth
regulators (2,4-D 2 ppm, NAA 40 ppm, triacontanol 5 ppm and
GA3 10 ppm, and control) in sub-plots at Rampur, Chitwan, Nepal
during winter-summer of 2003/04.
The treatments were replicated four times.
The application of 2,4-D and triacontanol increased number of short and
medium styled flowers thereby improving fruit set.
Yield components were superior in cv. Suryamukhi due to 2,4-D, and
triacontanol than Jwala.
Suryamukhi gave more fresh (11%), and oven dry (8%) fruit yields
2,4-D and triacontanol increased fruit yields by reducing fruit drop.
The application of growth regulators was found ineffective to control
flower and fruit drop in winter season.
32. Studies on training systems and NAA application on bell
pepper production in polyhouse
Y.R. Shukla, Deepa Sharma' and Upasna Tegta
Department of Vegetable Science,
Dr. Y.S. Parmar University of Horticulture and Forestry
Capsicum (Capsicum annuum L.) is an important off-season
vegetable crops grown in the mid-hills of Himachal Pradesh.
Production and productivity of this crop is low because of high
flower and fruit drop.
The present investigation was carried out to find out the best
training system and an appropriate concentration of
naphthalene acetic acid (NAA)
Three concentrations of Naphthalene Acetic Acid (N1- 5 ppm
spray, N2 - 10 ppm spray and N3 - 15 ppm spray) with Control
(no NAA application) were applied.
Three systems of training, viz. To (No Training), T1 (Two stem
Training) and T2 (Four stem training) were followed.
Two sprays of NAA @ 15 ppm proved best for plant
height, total number of flowers per plant, per cent flower
drop, per cent fruit set, days to first picking, number of fruits
per plant, fruit weight and total yield per plant.
34. Effect of training systems and NAA on various
horticultural traits of bell pepper
% fruit drops
Pandy, S.N., Sinha, B.K. 2007: Plant Physiology, Fourth Edition
Jain, V.K. 2009: Fundamentals of plant physiology, S. Chand &
International Journal of Horticultural Science 2007, 13 (3): 13–
23,Agroinform Publishing House, Budapest, Printed in Hungary,