this PowerPoint will explore post harvest pathology, you will see common types of pathogenic species that affects fruit and vegetables. secondly the PowerPoint will explore physiological disorders along with the different types of physiological disorders

1. Presented by:
Joseph Messam
Soren Mckenzie
Roshane Gayle

2. 
Upon completion of this presentation, you should be
able to explain:
 What is post-harvest pathology and its significance
 Common post harvest pathogens and symptoms
 Post harvest management and handling
 What is physiological disorders in fruits/vegetables
 Factors affecting these physiological disorders
 Types of physiological disorders
Presentation outline

3. 
 Postharvest pathology is a branch of phytopathology.
 This branch studies the diseases and microbial pathogens
produced by bacteria and fungi of fresh fruits, vegetables
and ornamentals (flowers).
 These diseases are initiated during growing, plant
development or during commercialization of these living
products and always show theirs symptoms during
storage.
(POST-HARVEST PATHOLOGY, 2012)
What is post harvest
pathology

4. 
 Postharvest pathogens are generally saprophytic
organisms (generally considered as microorganisms)
or weak pathogens
 (opportunistic), but sometimes they are necrotrophic
organisms which can only cause disease when
mechanical and/or chemical defenses of the living
part of the plant are diminished.
(POST-HARVEST PATHOLOGY, 2012)
Cont

5. 
 Postharvest diseases of fruits and vegetables are the
main cause of losses of fruits, vegetables and flowers
(ornamentals).
 Every year, they provoke numerous losses of
products with the resulting of creating economic
losses not only during handling but also during
storage and transportation.
(POST-HARVEST PATHOLOGY, 2012)
Cont

6. 
 Postharvest pathology is a comprehensive repository
of knowledge for farmers and processors on the
biology and control of postharvest diseases. This
knowledge can aid in the diagnosis of plant illnesses
and the reduction of post-harvest losses.
Importance of post
harvest pathology

7. 
Fungi (eukaryotes):
 Most important
 Reproduction and dissemination by abundantly
produced spores
 Infection through wounds or sometimes through
intact fruit surface.
(Adaskaveg, n.d.)
Causative agents of post
harvest diseases

8. 
Bacteria (prokaryotes):
 Mostly on vegetables
 Pectobacterium carotovora (Erwinia carotovora) is
the most important postharvest pathogen causing a
soft rot. Infections only through wounds.
(Adaskaveg, n.d.)
Cont

9. 
Penetration through wounds – Wound pathogens:
 Most common
 Only minor wounds required (micro-wounds).
 Wounds commonly occur before harvest (insect
injuries,wind damage, etc.) or more frequently
during and after harvest during handling, transport,
packaging.
(Adaskaveg, n.d.)
Method of penetration

10. 
Penetration of intact fruit:
 Through intact surface of mature fruit.
 Immature fruit: Quiescent infections are established
by some pathogens that remain inactive until fruit
mature.
 Colonization of flower parts, invasion of maturing
fruit
(Adaskaveg, n.d.)
Cont

11. 
 Penetration (through wounds or directly), inter- and
intracellular growth.
 Enzymatic activities dissolve host cell walls and
contents.
 Sometimes production of toxins that kill host cells.
Cont

12. 
 The majority of postharvest losses are caused by fungi
such as :
 Alternaria
 Aspergillus
 Botrytis
 Colletotrichum
 Diplodia
 Monilinia,
 Penicillium, Phomopsis, Rhizopus, Mucor, and
Sclerotinia.
Common Types Of Post-
harvest Pathogens species

13. 
Sclerotinia causes disease like Sclerotiorum rot
(Sclerotiorum rolfsii)
symptom includes Whitish growth with mustard-like
sclerotia on pods. In carrots symptoms include
water-soaked, white fungal growth, dark olive-green
lesions associated with collapsed tissues
Sclerotinia

14. 
Alternaria causes disease like
 Alternaria rot (Alternaria
solani)
 Symtoms includes circular, dry,
firm, shallow lesions covered
with dark, olive green to black
surface mycleial growth and
infected tissue is brown
Alternaria

15. 
Botrytis cause disease like
 Botrytis neck rot caused by Botrytis allii
and Botrytis aclada
 Symptoms includes stunted growth with
dead or dying outer leaves. Symptoms of
the infection are often first seen at the soil
line on the neck as water-soaked lesions.
 Under warm and wet conditions, the
disease progresses quickly, spreading up
the leaves and down the neck.
Botrytis

16. 
Aspergillus niger causes fruit rot
 Symptoms shown in includes
External decayusually close to
the calyx of fruit, with the rind
of the fruit slightly off-color
(e.g., paler red) and may show
some yellowish to brownish-
red discoloration.
Aspergillus

17. 
 Collectotrichum can cause
disease like antracnose. The
pathogen responsible is
Colletotrichum
lindemuthianum
 Symptom includes brown to
black sunken spots and
lesions on leaves, stems, and
pods. The center of
anthracnose lesions on pods
is covered with numerous
black dot-like acervuli.
Colletotrichum

18. 
Bacterial Species That Causes
Post Harvest Disease
 The major bacterial species that cause post
harvest loss includes
 Pseudomonas;
 Ralstonia
 Agrobacterium;
 Xanthomonas
 Erwinia,Xylella,Dickeya (dadantii and solani)

19. 
 Xanthomonas causes
bacterial speck
(Xanthomona sp) in
tomato
 Symptoms includes
dark brown to black
lesions of various sizes
and shapes on leaves,
fruit, and stems.
Xanthomonas

20. 
 Bacterial soft rots are caused by several types of
bacteria, but most commonly by species of gram-
negative bacteria, Erwinia, Pectobacterium, and
Pseudomonas.
 bacterial soft rots cause water-soaked spots. These
spots enlarge over time and become sunken and soft.
 Interior tissues beneath the spots become mushy and
discolored, with the discoloration ranging anywhere
from cream to black.
Pseudomonas

21. 
Cont

22. 
 Chemical control- Chemical fungicides are commonly
used for the management of postharvest disease in
vegetables.
 For postharvest pathogens which infect produce before
harvest, the fungicides should be applied at field level
during the crop season and or strategically applied as
systemic fungicides.
 At the postharvest level, the fungicides are often applied
to reduce infections already established in the surface
tissues of produce or they may protect against infections
occurring during storage and handling.
Post harvest disease
management

23. 
 Biological control- Biological control is used through
microbes such as fungi, bacteria, actinomycetes, and
viruses (bacteriophages) to control the postharvest
disease of vegetables
 Antagonistic yeast forms a biofilm to stick pathogen
and parasitize on the hyphae of the pathogen. Bar-
Shimon et al. reported that biocontrol efficacy of
yeast correlates with the production of lytic enzymes
and their ability to tolerate high concentrations of
salts.
Cont

24. 
 The use of natural botanical products would be a
supplement or an alternative to synthetic fungicide.
Examples include 1,8-cineole, the major constituent
of oils from rosemary (Rosmarinus officinale) and
eucalyptus (Eucalyptus globus),
Cont

25. 
 Maintenance of hygiene in all stages of postharvest
handling is critical to minimize the source of primary
inoculum for postharvest diseases
 Produce should be harvested during the day instead of
early morning. Field containers should be smoothed.
Containers should be cleaned.
 Sterilized packing and grading equipment, particularly
brushes and rollers, are used. Chlorinated water @ 100
ppm is commonly used for washing vegetables.
Post harvest handling

26. 
 Containers should not be overfilled, which causes
severe damage during stacking.
 Management of temperature is the most important
factor to extend the shelf life of fresh vegetables after
harvest.
 The relative humidity during storage should be
maintained at about 85–95% for most fruits and 95–
98% for vegetables. Transport vehicles should
always be cleaned and sanitized before loading.
Cont

27. 
 Physiological disorders refer to the breakdown of tissue
that is not caused by either invasion by pathogens
(disease-causing organisms) or by mechanical damage.
 They may develop in response to an adverse preharvest
and/or postharvest environment, especially temperature, or
to a nutritional deficiency during growth and development.
Physiological Disorder

28. 
 The action of environmental factors that are outside
the optimum ranges leads to the deterioration of
physiological process during the pre- and post-
harvest periods, which, in its turn, leads to the
incidence of physiological disorders (Burzo, 2001).
cont.

29. 
 Thus, physiological disorder may be defined as the
abnormal growth pattern or abnormal external or
internal conditions of fruits and vegetables caused
by adverse environmental conditions (such as
deviation from normal state of temperature, light,
moisture, nutrient, harmful gases and inadequate
supply of growth regulators) during growth in fields
or orchards or during harvest, storage, and
marketing.
cont.

30. 
 BER of tomato, capsicum, brinjal.
 Tip burn of lettuce, cabbage, cauliflower, broccoli,
etc.;
 IBS of potato;
 Cavity spot of carrot (Ca deficiency);
 Whiptail of cauliflower and broccoli (Mo deficiency);
Nutrients related
disorders

31. Black End Rot
•Tend to occur during
early fruit
•Development.
Associated with
nutrient (Ca) and/or
water deficiencies.

32. Tip Burn of leafy
vegetables
•Brown-black lesions at the
edges of leaves or other
harvested portions of
vegetable crops.
•Deficiency of potassium
•Most apparent when the
crop
approaches maturity

33. Internal Black Rot
•lesions are typically tan,
roughlycircular and
approximately 1/8 of an
inch in diameter.
•Deficiency of Boron
•underlying cause appears
to be the same i.e. cell death

34. Cavity spot
•This disorder appears
as a cavity in the cortex,
in most cases the
subtending epidermis
collapses to from a
pitted lesion.
•The cavity spot
disorder is induced by
deficiency of Ca.

35. 
 Yellowing of cabbage;
 Black leaf specks of cabbage,
 Phenolic browning, bitterness and scaling or silvering of
carrot;
 Greening of potatoes and onions;
 Sprouting of potatoes, onion and garlic;
 Watery scales, translucent scales and freezing injury of
garlic and onion;
 Ammonia injury in onion;
 Bitterness in pepper
Storage related
disorders

36. Yellowing of
vegetables
•Leaves become dull
yellow, curl, and plant
may die.
•Cabbage yellows is
caused by the Fusarium
soil fungus that infects
plants usually where
the soil is warm

37. Silvering of carrots
•Carrots can sometimes
develop a scaly surface
in storage. The carrot
surface has a white,
flaky appearance that
looks similar to
dandruff.
•This symptom
appears when carrots
become dehydrated.

38. 
 Root breakage and splitting of carrot;
 Brown center and hollow heart of potato;
 Growth cracking of potato and tomato;
 Loose head of cabbage;
 Elongated root or forking of radish and carrot;
 Buttoning of broccoli and cauliflower;
 Bolting of leafy and root vegetables;
 Bracting of cauliflower;
 Sunscald of tomatoes, capsicum, etc.(lycopene synthesis)
Growing and weather
related disorders

39. Hollow heart
•Characterized by a
region of cell death in the
pith of the tuber which
results in brown tissue.
•Hollow heart is
characterized by a star
shape hollow in the
center of the tuber.
•Main cause is uneven
moisture in environment.

40. Temperature injury
Temperature is the most
important factor
determining deterioration
rate, and rapid loss of
quality can occur after
harvest under field
conditions. Decreasing the
temperature reduces the
product's metabolism
(respiration and ethylene
production), water loss and
the growth of decay-causing
fungi and bacteria

41. freezing injury in
apple fruit
. Freezing injury
symptoms include tissue
browning, blackening,
wilting or curling of
leaves and stems. It is
important to remember
that younger plant tissue
is more vulnerable to
freezing than more
mature tissue. In
addition, plant tolerance
to freezing temperatures
increases as the plants are
acclimated to the cold
temperatures.

42. 
 DISEASE is the illness, having characteristics set of signs
and symptoms, caused by pathogens(virus, bacteria).
Where changes in biological functions occur. E.g.- Rust,
Powdery Mildew etc.
 DISORDER is the disturbance or disarrangement in the
plant body which affects the function of various
physiological functions or body these are due to internal
factors like Genetically inherent or deficiency of specific
nutrient like .
Difference between
Disease and disorder

43. 
 Adaskaveg, J. (n.d.). Postharvest Disease Management -Principles and
Treatments. https://ucanr.edu/datastoreFiles/234-2739.pdf
 https://www.intechopen.com/chapters/79995. (n.d.).
Www.intechopen.com.
https://www.intechopen.com/chapters/79995
 POST-HARVEST PATHOLOGY. (2012). Upct.es.
https://autentica.upct.es/apps/guiasdocentes?codDep=D026&an
yAnyaca=2015-
16&steCod=GRADO&assCodnum=518109015&locale=en#:~:text=
Postharvest%20pathology%20is%20a%20discipline
 Burzo, I., Delian, E. and Craciun, C. 2001. Ultrastructural
changes induced by the physiological disorders in fruits and
vegetables. Acta. Hort
Reference