This document discusses several bacterial diseases that affect important pome and stone fruits grown in Pakistan. It describes the causal organisms, symptoms, and management strategies for blister spot, crown gall, fire blight, and bacterial spot/canker diseases of apple, pear, peach, and other fruits. The diseases are caused by bacteria such as Pseudomonas, Erwinia, Agrobacterium, and Xanthomonas species. Symptoms vary by disease but include leaf spots, cankers, shoot blights, and galls or tumors on roots and stems. Management involves practices like sanitation, resistant varieties, and antibiotic sprays to control the spread and reduce impacts of these bacterial diseases.

1. Bacterial Diseases of Pome Fruits in Pakistan
 Group Member’s
Mohammad Adeel Zahid
Mohammad Farhan
Mohammad Nouman
Mohammad Iqbal
Zaib ul hassan
Mohammad Awais

2. Pome Fruit
 Pome fruits are members of the plant family Rosaceae, sub-family pomoideae.
 They are fruits that have a "core" of several small seeds, surrounded by a tough
membrane. The membrane is encased in an edible layer of flesh.
 Trees are deciduous and have a dormant winter period that requires cold
temperatures for the tree to properly break dormancy in spring.
 Pome fruits are grown from spring blossom and harvested from late summer
through to late autumn.

3. Examples of Pome Fruits
 1. Apple
 2. Pear
 3. Peach

4. Apple
 Scientific Classification
 Kingdom: Plantae
 Order : Rosales
 Family : Rosaceae
 Genus : Malus
 Species : M.domestica

5. Introduction
 Apple is a symbol of health, beauty and love.
 It may be called as king of fruits in temperate Regions
 It ranks third in consumption after citrus and banana fruits in tropical countries.
 Apple is a very nutritious, aromatic and delicious fruit.
 It is very rich in Vitamin C, B and A.
 It contains about 41% sugar besides essential minerals in appreciable amounts.
 Cultivated varieties of apples belong to group Pyrus and sub-group malus.

6. Bacterial Diseases of Apple
Blister Spot : Pseudomonas syringae pv.papulans
Crown Gall : Agrobacterium tumefaciens
Fire Blight : Erwinia amylovora
Hairy root : Agrobacterium rhizogenes

7. Blister Spot
 Casual organism
Pseudomonas syringae pv.papulans
 Introduction:-
 Although over 20 cultivars of apple have been reported as susceptible to the
bacterium.
 Disease is usually of economic importance only on Mutsu in New York State.
 If uncontrolled, the disease generally affects 5 to 60 per cent of the fruit in an
orchard.
 The bacterium does not cause extensive decay of the fruit, but makes them
unsuitable for fresh market use.

8. Symptoms
Infections of blister spot are first noticeable 2-3 months after petal fall as small,
green, water-soaked, raised blisters that develop at fruit stomata.
These spots result in purplish black lesions.
As the fruit increase in size, the lesions expand to about 5 mm and become
darkened.

9. Symptom

10. Management;-
 Disease could be controlled with three well-timed antibiotic spray.
 The first applied no later than 2 weeks and the others applied weekly again.

11. Crown Gall
 Casual organism
Agrobacterium tumefaciens
. Introduction:-
 Crown gall can affect a wide range of crops , including woody ornamentals,
tree fruits and small fruits.
 Some vegetable and herbaceous ornamentals are also susceptible but these
crops are less commonly affected.

12. Symptoms
 Galls are usually restricted to the roots, lower stems and lower branches of
infected plants.
 In some cases, crown gall may occur in the upper branches.
 Galls are spherical, lumpy and rough, varying in size from 1/2 inch to several
inches in diameter.
 Affected plants may be stunted, produce small chlorotic leaves and become
more sensitive to environmental stresses (particularly winter injury).
 Severely infected plants may decline and eventually die.

13. Symptoms:-

14. Symptoms:-

15. Cause and Disease Development
 Crown gall is caused by the soil-borne bacterium , Agrobacterium tumefaciens.
 This organism enters susceptible plants through fresh wounds made during
transplanting, cultivating, grafting and pruning.
 Other wounds inflicted by people, severe weather, insects or other animals may
also serve as avenues of infection.

16. Disease Management
 AVOID WOUNDING:-
 susceptible plants at or near the soil line.
 PRUNING INFECTED BRANCHES :-
 well back into healthy tissue will serve as an effective means of control when
galls are limited to the above ground portions.
 Cutting tools should be disinfested with 10% household bleach, 70% alcohol or
Lysol between each cut in order to prevent transmitting the bacteria from one
cutting to the next.

17.  PLANT REMOVAL AND DESTRUCTION
 May be necessary when crown gall infections are extensive, especially on the
lower stem and roots.
 Avoid replanting the site with trees or shrubs known to be susceptible to crown
gall (e.g. apple, pear, brambles, forsythia, grape, honeysuckle, pecan, rose,
Russian-olive and walnut ).
 Plants known to be resistant to crown gall include: hemlock, holly, hornbeam,
linden, pine, spruce.

18. Pear
 Scientific name: Pyrus
 Family: Rosaceae
 Sub-Family: Pomoideae
 Genus: Carl Linnaeus

19. Introduction
 Pear are sweet juicy yellow or green fruit with a rounded shape that becomes
narrower towards the stalk.
 Pears are picked when they are almost ripe.
 Pears ripen best at room temperature.
 The cultivation of the pear in cool temprate climate.
 A pear tree can grow up to 20 m. high.
 In Pakistan Pears come in different types and are available usually from
September to December.
 Used in Salads, Pudding, Cake, Tart, Juice

20. Fire Blight
 Casual organism
Erwinia amylovora
 Genus: Erwinia
 Family: Enterobacteriaceae

21. Introduction
 Fire blight, unlike most fruit tree diseases, is caused by a bacteria
 It can be spread from tree to tree by bees, aphids, pear psylla, and other insects.
 The bacteria mainly attack twigs and young shoots.

22. Symptoms and Signs
 Symptoms of fire blight can be observed on all above ground tissues
 It is including blossoms, fruits, shoots, branches and limbs, and in the rootstock
near the graft union on the lower trunk.
 Generally, symptoms of fire blight are easy to recognize and distinguishable
from other diseases.

23. Disease Symptoms
 The bark at the base of blighted twigs becomes water soaked, then dark,
sunken and dry;
 cracks may develop at the edge of the sunken area.
 Young twigs and branches die from the terminal end and appear burned or deep
rust colored.
 Branches may be bent,
 Dead leaves and fruit remain on the branches

24. Symptoms

25. Symptoms

26. Controls and Management
 Pruning to Control Fireblight :
 Remove all suckers and cut off any infected branches before the bacteria attack
the tree further.
 Cut off the wilting branch at least 8 inches below the point of last visible wilt.
 After each cut, dip the shears in a solution of 1 part household bleach to 9 parts
water to avoid transmitting bacteria from one branch to another
 Remove other plants that may serve as hosts for the disease including wild
apples

27. Control of fire blight is based on several steps
 Plant resistant or tolerant varieties: Kieffer, Orient, Garber, or Douglas.
 Maintain balanced fertilizer level.
 Do not use excess levels of nitrogen.
 Remove overwintering bacteria cankers by pruning.
 Make pruning cuts 8 to 12 inches below visible sign of disease.
 Apply bactericides on 5 day intervals between early bloom and late blooms.

28. Crown Gall
 Casual organism
 Agrobacterium tumefaciens
 Introduction:
 This bacterium can infect a wide range of herbaceous and woody plants.
 The bacterium only carries the gall-causing entity ,a plasmid, that contains its
own genetic material.
 After the bacterium enters the host, the plasmid DNA is transferred into the
host plant cell where it stimulates the production of more plant cells.

29. Symptoms
 Roots Galls are initially white, spherical, and soft
 Galls 1/4 inch to several inches in diameter
 Bacteria survives and persists in the soil for many years.
 It invades recent wounds on stems or roots.
 Swelling can be seen 14 days following entry.
 Tissue near the gall is crushed.

30. Symptoms

31. Management
 Nursery:-
 Purchase crown gall-free plants.
 Propagate only from crown gall-free plants.
 Avoid wounding plants near soil line.
 Disinfest grafting tools.
 Avoid planting in areas known to be infested with the bacterium.
 Dip or spray seedlings or cuttings in a formulation of strain 84 of
Agrobacterium radiobacter which is a biological control agent.

32. Home or Commercial Planting
 Plant only crown gall-free plants.
 Remove severely affected plants and do not replace with susceptible cultivars.
 Plants not severely affected can be grown if fertilized, watered, and otherwise
cared for well. The disease will continue but probably not kill the plant.

33. Peach
 Casual organism : Prunus persica
 Family : Rosaceae
 Genus: Chokecherry

34. Introduction
 It bears an edible juicy fruit called a peach and it also known as nectarine.
 Both same species but different fruits.
 Peach fruit present the fuzz on the skin,
 Nectarine are characterized by the absence of fruit-skin (fuzz-less fruit);
 Peaches grow in a fairly limited range in dry and temperate climate.
 Most cultivars require 500 hours of chilling around 0 to 10 °C .
 Temperature required for mature the crop is 20 and 30 °C.
 Both are best stored at temperatures of 0 °C (32 °F) and high-humidity.

35. Bacterial spot or bacteriosis
 Causal organism
 Xanthomonas arboricola pv. pruni or X. campestris pv. Pruni
 Introduction:
 "Bacterial spot" sometimes known as "bacterial shot hole“
 Present especially on older peach trees.

36. Symptoms and Signs
 Disease can affect foliage, tender twigs, and fruit.
 Presence of water soaked spots on leaves.
 Spots enlarge, darken, purple and necrotic.
 Heavy defoliation early in the summer can reduce the size of the fruit and
weaken the tree.
 Small circular brown spots on the surface of the fruit.

37. Symptoms

38. Symptoms

39. Management
 Good tree vigour should be maintained by proper pruning.
 Judicious application of fertilizer, and watering when necessary.
 Excess nitrogen may aggravate the disease.
 Use resistance varieties.
 Avoid the insecticides during bloom.

40. Bacterial disease of canker
 Causal organism
 Pseudomonas syringae pv. Syringae
 Introduction:
 This disease is caused by the two related bacterial species, Pseudomonas
syringae and P. morsprunorum.
 The disease can occur on all stone fruit and is known as gummosis, blossom
blast, spur and twig blight, sour sap, and dieback.
 The bacteria have a wide host range, can systemically invade host tissue
without symptoms, and can grow epiphytically on host and nonhost leaf
surfaces.
 As a result, control of this pathogen is complicated.

41. Symptoms
 The disease occurs on branches, twigs, buds, leaves, and fruit.
 Cool, wet weather after bloom, leaf and fruit infections are common.
 Leaf infections, especially appear as water-soaked spots that become brown
and dry.
 Surrounded by yellow halos.
 Lesions on green fruit are brown and surrounded by water-soaked tissue.

42. Symptoms

43. Symptoms

44. Management
 Practices that minimize wounding and freeze injury.
 Maximize good cultural practices will reduce the incidence of bacterial canker.
 The bacteria can be transmitted by pruning tools so these should be disinfected
between trees if bacterial canker is present.

45. Control:
 Apply lime before planting to adjust pH to 6.5 .
 Plant trees which have been grown in fumigated soil or certified to be free of
nematodes.
 Early pruning is especially hazardous on old peach land.
 Remove and destroy promptly all dead or dying trees .
 Dip pruning tools between trees in a 9 parts water and 1 part Chlorox solution
in infected orchards.