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
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.
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.
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
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
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.
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.
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.
40.
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.
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
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