Fire blight is a contagious disease affecting pears and other rosaceous plants. It is caused by the bacterium Erwinia amylovora. The disease spreads through pollen carried by bees and rain splash. Symptoms include scorched branches and shoots. Management involves pruning out infected plant parts, controlling insect vectors, and applying copper and streptomycin sprays. Pear scab, caused by the fungus Venturia inaequalis, produces olive-green spots on leaves and fruit. It is controlled through fungicide applications timed with ascospore release. Brown rot, caused by the fungus Monilinia spp., infects peaches through mummified fruits. It is managed by removing plant debris

1. UNIVERSITY OF HORTICULTURE SCIENCE, BAGALKOT
DIEASES OF FRUIT, PLANTATION, MEDICINAL AND AROMATIC CROPS

2. FROM TO
 Savitha H R Dr. Shankarappa K S
 Sakshi T R Asst. Professor
 Sinchana Dept. of Plant Pathology
COH, Bengaluru

3. DISEASES OF PEAR

4.  Scientific name: Pyrus communis
 Family: Rosaceae
 Pear is one of the important fruit of temperate
zone.
 It is popular for its delicious taste.
PEAR

5. Major diseases of pear
 Pear scab : Venturia inaequalis
 Powdery mildew : Podosphaera leucotricha
 Pacific Coast Pear Rust : Gymnosporangium libocedri
 Fire blight : Erwinia amylovora
 Crown gall :Agrobacterium tumefaciens
 Fabraea Leaf Spot : Fabraea maculate
 Pear decline : Phytoplasma like organism
 Phytophthora Crown Rot, Collar Rot, and Root: Phytophthora sp.

6. Fire Blight
 The causal pathogen is Erwinia amylovora,a Gram-negative rod
shaped bacterium in the order Enterobacterales.
 Fire blight is a contagious disease affecting apples, pears, and some other
members of the family Rosaceae.
 Discovered by Erwin.F.Smith.
 First report of fire blight on Asian pear in korea.
 Fire blight attacks blossoms, leaves, shoots, branches, fruits, and roots.
 It gets its name from the burnt appearance of affected plants.

7. Distribution
 It has destroyed pear and apple orchards in much of North
America, in parts of Europe, and in new Zealand and Japan .
 Fire blight is a contagious disease affecting apples, pears, and
some other members of the family Rosaceae.
 It gets its name from the burnt appearance of affected plants.

8. Etiology
 Disease is disseminated through bees and other pollinating insects and
also by rain water splash.
 Primary source of inoculum: Bacterial cells present on cankers, fallen
leaves on the ground, on cracks and cravices.
 Secondary source of inoculum: Rain water splash borne bacterial cells

9. Epidemiology
 In warm moist spring weather, droplets of bacterial ooze appear on the
surface of “holdover” cankers.
 Colonisation will be heavily decided by temperature, 21–27 °C is most
favourable.
 Rain or heavy dew will allow procession further.
 High humidity favor infection.
 Precise environmental conditions are needed for infection to occur and as a result disease incidence
varies considerably from year to year.

10. SYMPTOMS
 Infected parts appear to be scorched by fire.
 A watery ooze may exude from infected plant part. The disease may kill entire trees.
 Fruits infected early remain small, appear shrivelled, dark and ‘water soaked’. They remain attached to
the cluster. Fruits infected late are less tasty.
 Severe infections result in fruit turning entirely black and shriveling.

11. DISEASE CYCLE
 Erwinia amylovora overwinter in cankers formed during the
previous season, serving as the primary inoculum.
 Bacteria exude from ooze in the spring when temperatures support
optimal development.
 Honeybees and other insects are attracted to bacterial ooze and can
spread bacteria to susceptible tissue
 These bacteria multiply rapidly resulting in secondary infections.
 Shoots remain highly susceptible to infection until vegetative
growth ceases and the terminal bud is formed.

12. Disease cycle of fire blight

13. Management
 Reduce primary inoculum by removing infected plant materials after winter
pruning.
 Control insect vectors in the orchard.
 Avoid use of susceptible cultivars.
 Maintain proper and balance in orchard soil nutrition so as to discourage
excessive tree vigor.
 Proper pruning is effective, and minimize summer pruning.
 Avoid use of excessive nitrogen fertilizers

14. Management
 Chemical methods : Spray of Copper Oxychloride (0.3%) and
Streptocycline (0.05%)
 Streptomycin , copper sulfate sprays have been used to prevent new
infections.
 Biological controls :beneficial bacteria or yeast can also prevent fire
blight from infecting new trees.
 Apply apogee (prohexadione-calcium) a growth inhibitor that can reduce
shoot blight
 Control of sucking insects create wounds through which fire blight
bacteria can enter.

15. Leaf blight
 Causal organism: Fabraea maculate
 fungal disease that spreads quickly and can defoliate
trees
 Infects the leaves, fruit, and shoots of pear and quince
trees and the leaves of apple trees.

16. DISTRIBUTION
 Mostly seen in northeast and Midwest ,but in southeast,
shoot infection is significant.

17. ETIOLOGY
Primary source of inoculum: fungus present on leaves on the
ground, on cracks and cravices.
Secondary source of inoculum: Rain water splash borne fungal
cells

18. EPIDEMIOLOGY
 The disease is favoured by temperatures between 25–30 °C,
and by wet conditions.
 usually appears in more temperate environments
 high relative humidity
 outbreak can become serious within two days of infection.
 Occurs from spring to summer

19. SYMPTOMS
 Small, circular green spots occur on the leaves.
 Later spots become angular, deep purple to black.
 The spotted area falls and shot holes are formed.
 Severe disease infection leads to defoliation which devitalizes the tree.
 Circular spots are noticed on fruits. These are water-soaked initially and become black.
 Due to intense spotting on the fruits, pitting or cracking occurs in the vicinity of spots.
 Twig canker results in the death of branch.

20. DISEASE CYCLE
 The sexual spore stage develops on fallen, overwintered leaves.
 Conidia, asexual spores, may also develop in the spots on overwintered
leaves, or they may be produced in the previous season's shoot infections.
 Often the first infections do not occur until mid-June to the first of July.
 Secondary infections begin about 1 month later and reoccur throughout the
season during periods of rain.

21. MANAGEMENT
 This disease can be controlled by using protectant
fungicides.
 Early-season spray shedule for control early-season leaf
spot infections. Where ascospores and conidia of the fungus
develop after petal fall, summer fungicide treatments are
needed

22. FUIT SPOT

23. ETIOLOGY
 Primary inoculmn : Dormant Twigs and mummified fruit
 Secondary inoculmn : Leaf spots ,spores
 Fruit rot pathogen were captured by the spores traps
 Peak dissemination occurs during flowering

24. EPIDEMIOLOGY
 Warm weather conditions with
 Temperature- 28-32°C
 Relative humadity- 80-90 % and
 Intermittent rainfall

25. SYMPTOMS
 Lesions cause the fruit to crack and drop.
 Lesions on current season's shoots may be observed as small inconspicuous,
purplish-black spots.
 Some lesions develop into superficial cankers.
 Early defoliation leads to small fruit, weak bud formation and fall
blossoming.
 Infected fruit has no sale value .

26. Disease cycle
 The four-celled conidia (Entomosporium maculatum), with a distinctive
insect-like appearance.
 spread mainly from overwintering leaf litter, and some from twig cankers, by
splashing water from rains or overhead irrigation.
 Lesions begin to appear about 7 days after the beginning of an infection period.
 Susceptibility of leaves and fruit to infection does not decrease with maturity.

27. • This disease can be controlled by using protectant fungicides.
• Early-season spray shedule for pear scab should also control
early-season leaf spot infections.
• Ascospores and conidia of the fungus develop after petal fall,
summer fungicide treatments are needed
MANAGEMENT

28. Diseases of Peach
 Family: Rosaceae
 Botanical Nmae: Prunus persica
 Origin: china

29. Major Disease of Peach
1. Leaf curl –Taphrina deformans
2. Rust – Puccinia
3. California peach blight- Stigmina carpophila
4. Scab – Venturia carpophila
Minor Diseases of Peach
1. Powdery mildew –Sphaerotheca pannosa var. persicae
2. Frosty mildews – Cercosporella persicae
3. Target leaf spot – Phyllosticta persicae
4. Bacterial leaf spot -Pseudomonas syringae pv persicae
5. Gummosis: Prunus dwarf virus
6. Mosaic Virus disease-Peach Mosaic Virus
7. Necrotic Leaf spot - Necrotic Leaf Spot Virus .
8. Peach- Phytoplasma like organism
9. Peach yellows: Phytoplasma like organism

30. Leaf curl
 Causal organism: Taphrina deformans

31. etiology
 Mycelia are intercellular and not produce specific
ascocarp.
 Asci are produced individually
 Each ascus bears eight ascospores
 Primary source of inoculum: Dormant mycelia in the
affected stem newly formed buds.
 Secondary source of inoculum: Air borne conidia.

32. epidemiology
 The disease is prevalent in areas where cool and misty spring
weather prevails .
 Dry hot weather hastens defoliation.

33. The disease first appears in the early spring as the leaves begin to unfold
• The leaf blade thickens and midrib turns yellow and curl
• Finally infected leaf turns to reddish purple tint
• The reddish velvety surface of lamina is soon covered with a whitish grey bloom of the fungus on the
upper surface
• Both the leaves and petiole may curl
• Affected leaves die and drop immaturely
• Twigs become pale green to yellow, swollen, stunted and exude gummy material
• Flowers and fruits are also infected & drop prematurely
Symptoms

34. Management
 Removal & burning of infected leaves and shoots reduce the
spread of the disease
 A dormant spray with Bordeaux mixture (1%) with an
adhesive and a winter spray with Bordeaux mixture (1%)
before bud burst controls the disease.

35. Brown rot
 Brown rot, caused by Monilinia spp
 most economically harmful fungal
diseases for peach and other stone
fruit growers worldwide.

36. Brown rot of peach

37. ETIOLOGY
 Primary Inoculum—starts the epidemic each season after a period of no
disease activity
 mummified fruit on the ground produce the sexual ascospores of the
pathogen, and twig cankers that produce asexual conidia. These ascospores
and conidia infect blossoms, causing a blossom blight that progresses into a
twig blight and canker.
 Secondary Inoculum—produced during the epidemic within a season,
resulting in additional cycles of infection throughout the disease progression.
 conidia are produced on the initially blighted blossoms and twigs.

38. ETIOLOGY

39. EPIDEMIOLOGY
 Infection can occur over a broad range of temperatures
(32°F to 86°F; 0°C–30°C), with an optimum temperature
range of 72°F to 77°F (22°C–25°C). However, if plant material
remains wet for 24 hours or more, brown rot fungus
infection is most likely to occur, regardless of the air
temperature.
 Plant materials must remain wet for 3–5 hours to initiate
fruit infection.

41. symptoms
 Brown rot damage is easily observed on fruit,
blossoms, and shoots. Infected blossoms will wilt
and turn brown in color.
 Tan-gray tufts of masses of conidia will form on
the outside of the flower shuck
 Infected mature fruit will appear as soft, brown
spots occurs slowly decay and shrivel until brown
to black in color

42. management
 Removal of fruit mummies and other infected plant debris from the field
 Sanitation measurements can be done from harvest in winter months to bloom
 Weak, dead, and cankered branches and twigs should be pruned throughout the winter and spring.
 The use of microjet irrigation is recommended to avoid wetting fruits, flowers, branches, and twigs
 Fruits that appear stunted should be thinned as well to remove another possible source of inoculum
 avoid excess nitrogen fertilizer, because too much nitrogen can lead to the greater susceptibility of the
tree to disease

43. CHEMICAL METHODS
1. use copper fungicides or sulfur powders should be applied weekly
to infected trees starting when the blossoms are just beginning to
open and continuing throughout the growing season.
2. Use Tanglefoot® Pruning Sealer to seal all cuts and wounds and
protect against insects and disease organisms.
3. Organocide® Plant Doctor is an earth-friendly systemic fungicide.
Apply as a foliar spray (1 tsp/ gallon of water) to combat this
destructive stone fruit problem.

44. Powdery mildew
 Causal organism:Sphaerotheca pannosa var. persicae.

45. ETIOLOGY
 Primary source of inoculum: Dormant mycelia
 Secondary source of inoculum: Air borne conidia.

46. ETIOLOGY
 Mycelia –septate, subepidermal houstoria
 Asexual spores-Conidia
 Asexual fruiting body- oidium
 Sexual spore- Ascospore
 Sexual fruiting body- Cleistothecium
 Primary source of inoculum: dormant mycelia in infected dormant buds
 Secondary source of inoculum- Barrel shaped conidia

47. EPIDEMIOLOGY
 Warm weather conditions with
 Temperature- 28-32°C
 Relative humadity- 80-90 % and
 Intermittent rainfall

48. SYMPTOMS
 Whitish powdery growth of fungus appear on leaves, young shoots and fruits.
 The young leaves are coated with a thick layer of mycelium and as a result they
become narrow and curled.
 Terminal portion of the shoot is covered by white powdery mass.
 White powdery growth later turns in to pinkish and finally dark brown in
colour.
 Epicarp of fruit becomes leathery and hard.

49. MANAGEMENT
CULTURAL CONTROL:
 Pruning of canker affected parts and CoC paste at cut ends.
 Spraying 5% urea on fallen leaves.
 Optimum plant density
 Use of drip irrigation
CHEMICAL CONTROL :
 Calcium Oxychloride (0.3%) spray on plant.
 Bordeux mixture (1%) spray or
 Streptocyclin (0.05%) spray
 Biological control
 Use of Erwinia herbicola and Psuedomonas fluorescens as antagonistic
sprays.

50. Bacterial spot
 Causal organism: Pseudomonas morus-prunorum.
 Brown spot of pear is a fungal disease producing high
economical losses in several pear-growing areas in Europe.
 E. Simmons, that was first reported in 1975 in Italy in the
Emilia-Romagna region

51. EPIDEMIOLOGY
 The disease is favoured by temperatures between 25–30 °C, and by wet
conditions.
 usually appears in more temperate environments
 produce high amounts of conidia at 20–25°C under high relative humidity conditions

52. Bacterial Spot Life Cycle
 The pathogen for bacterial spot overwinters in protected areas such as cracks in the bark and in leaf
scars that were infected the previous season. As temperatures rise over 65 degrees and budding
begins, the bacteria begin to multiply.
 They are spread from cankers via dripping dew, rain splashing or wind. Severe fruit infections occur
most frequently when there is ample rainfall combined with high humidity.
 The infection is also most severe when the trees are planted in light, sandy soil and/or if trees are
stressed

53. Life cycle

54. SYMPTOMS
.
 Small, circular green spots occur on the leaves.
 Later spots become angular, deep purple to black.
 The spotted area falls and shot holes are formed.
 Severe disease infection leads to defoliation which devitalizes the tree.
 Circular spots are noticed on fruits. These are water-soaked initially and become
black.
 Due to intense spotting on the fruits, pitting or cracking occurs in the vicinity of
spots.
 Twig canker results in the death of branch.

55. MANAGEMENT
 Cut and burn the infected plant parts.
 Spraying with zinc sulphate-lime solution as a mixture is effective.

56.  Biocontrol agents :Trichoderma koningii and T. viride
 Chemical methods :copper, oxytetracycline and syllit+captan however, repeated applications