This document describes 27 fungal diseases that affect papaya crops. It provides the symptoms and control methods for each disease. Some of the major diseases discussed include anthracnose caused by Colletotrichum gloeosporioides which causes circular brown lesions on fruits; angular leaf spot caused by Leveillula taurica which causes powdery whitish spots on leaves; and Phytophthora blight caused by Phytophthora species which causes water-soaked lesions and fruit rot. The document emphasizes the importance of cultural control methods like removing diseased plant parts and using resistant varieties as well as chemical control using appropriate fungicides to manage these papaya diseases.
This ppt will help Agricultural professionals to diagnose banana diseases and the management strategies. This is a compilation of important diseases of banana prevalent in India which contains some of my own photographs and others collected from Web. This is intended only for educating students and other agricultural field staff.
This ppt will help Agricultural professionals to diagnose banana diseases and the management strategies. This is a compilation of important diseases of banana prevalent in India which contains some of my own photographs and others collected from Web. This is intended only for educating students and other agricultural field staff.
Damping off, collar rot/gummosis of citrus and Papaya and root rot of juteDinesh Ghimire
This was presented by one of the group of students to our Asst. professors Mr. and Mrs. Poudel (Pathology) in 2017. By B.Sc.Ag Paklihawa IAAS campus, Full phase 6th batch
a brief description on diseases of pea their symptom and casual organism.
Content is for eduacational purpose and truly for students ,scientist and farmers.
students presentation
Wilt is a pernicious disease of guava in India.
In India the disease was first recorded near Allahabad in 1935 . The infection was reported 15 -30 %.
The disease is a serious threat to guava cultivation in U.P. In West Bengal it reduces the yield in affected orchard by 80% .
The disease is also prevalent in Haryana Rajasthan , A.P ,
Punjab and M.P.The exact cause of the disease is still not fully understood but the pathogens viz. Fusarium oxysporum f. sp. psidii (Prasad, Mehta & Lal), Rhizoctonia spp. (Taub.) and various pathogens are reported by different workers may be the incitant of the disease.
Survival and spread:
Through movement of plants containing sick soil in virgin areas.
Short distance spread is by water.
Root injury predisposes wilt disease.
It has forced uprooting of about 150 acre of guava orchard in Panjab and 300 acres in Haryana during 1971-81.
A serious and important disease that affects banana and got huge loss in its yield and growth. Some factors that are responsible for its cause and measures to eliminate this disease are briefly discussed.
It contains basic details about the etiology, symptoms, disease cycle and management practices for the control of disease : Wilt in Chickpea, Lentil and Arhar(Pigeon pea).
The overall description of major diseases of Rice or Paddy crop is ellustrated in presentation. The students prepairing for Agriculture can feel helpful. Thank You!
Damping off, collar rot/gummosis of citrus and Papaya and root rot of juteDinesh Ghimire
This was presented by one of the group of students to our Asst. professors Mr. and Mrs. Poudel (Pathology) in 2017. By B.Sc.Ag Paklihawa IAAS campus, Full phase 6th batch
a brief description on diseases of pea their symptom and casual organism.
Content is for eduacational purpose and truly for students ,scientist and farmers.
students presentation
Wilt is a pernicious disease of guava in India.
In India the disease was first recorded near Allahabad in 1935 . The infection was reported 15 -30 %.
The disease is a serious threat to guava cultivation in U.P. In West Bengal it reduces the yield in affected orchard by 80% .
The disease is also prevalent in Haryana Rajasthan , A.P ,
Punjab and M.P.The exact cause of the disease is still not fully understood but the pathogens viz. Fusarium oxysporum f. sp. psidii (Prasad, Mehta & Lal), Rhizoctonia spp. (Taub.) and various pathogens are reported by different workers may be the incitant of the disease.
Survival and spread:
Through movement of plants containing sick soil in virgin areas.
Short distance spread is by water.
Root injury predisposes wilt disease.
It has forced uprooting of about 150 acre of guava orchard in Panjab and 300 acres in Haryana during 1971-81.
A serious and important disease that affects banana and got huge loss in its yield and growth. Some factors that are responsible for its cause and measures to eliminate this disease are briefly discussed.
It contains basic details about the etiology, symptoms, disease cycle and management practices for the control of disease : Wilt in Chickpea, Lentil and Arhar(Pigeon pea).
The overall description of major diseases of Rice or Paddy crop is ellustrated in presentation. The students prepairing for Agriculture can feel helpful. Thank You!
A brief information about the SCOP protein database used in bioinformatics.
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(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
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Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
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Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
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Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
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of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
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Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
1. Fungal diseases of Fruit crops-
Papaya
Vaishali S.Patil
Professor, Department of Botany
Shri Shivaji College of Arts, Commerce & Science Akola
2. 1.Alternaria fruit spot- caused by Alternaria alternata
Symptoms-depressed, circular to oval, lesions that eventually
become black as a result of mass sporulation. Lesons are
restricted to the surface of the fruit and do not cause extensive
rotting of the flesh. However, lesions from multiple infection
sites can coalesce as they expand and eventually cover the
entire fruit surface.
Control-A single postharvest water dip of 20 min, fungicides.
3. 2.Angular leaf spot caused by Leveillula taurica
Symptoms- Petioles, stalks and flowers are rarely
affected and fruits are occasionally infected. It
penetrates the interior leaf tissues. On the ventral side
powdery, whitish spots appear that gradually expand.
On the dorsal side, yellow spots of varying intensity
develop. On the dorsal side, powdery spots may also
develop. Spots may later become necrotic.
Control- Crop Resistance, proper irrigation, chemical
control.
4. 3.Anthracnose caused by Colletotrichum gloeosporioides
Symptoms -The spots on fruits first appear as brown
superficial discolouration of the skin which develops into
circular, slightly sunken areas. Gradually the lesions coalesce
and sparse mycelia growth appears on the margins of the
spots. Infection at early stages of fruit results in
mummification and deformation.
Control-removing the fruit as soon as it matures, removing all
dead leaves and fruit from the vicinity of the plants, and
removing infected fruits from the trees.
5. 4.Black spot caused by Asperisporium caricae,
Cercospora papayae, Phomopsis caricae-papayae
Symptoms- Water-soaked spots appear on the upper
leaf surface. Later, small, black spots are visible on the
underside of the leaf. Black spots may also be found
on the fruit. The tissue beneath them becomes corky,
but the fruit does not rot.
Control-Fungicide
6. 5.Blossom spot caused by Choanephora cucurbitarum
Symptoms- Ringspot disease are exhibited on the foliage
fruit and main stem of the plant. The main stem growing at the
time of infection frequently develops dark-green spots and
streaks of an oily appearance. These are usually most common
on the middle two-thirds of the stem.
Control- Refrigerated storage and careful handling will
minimize decay postharvest.
7. 6.Black rot caused by Mycosphaerella caricae
Symptoms- Spots appear on leaves, flowers and young fruit.Fruit
surface lesions are slightly sunken, circular, black. Margins of lesions are
light brown and translucent. The lesion surface dries and wrinkles with
age and turns black as it becomes covered with hyphae and pycnidia of
the imperfect stage. Under humid conditions it is common to see light-
colored tendrils of pycnidiospores oozing from pycnidia. The infected
tissue is dry, firm and is initially tan in color and eventually turns black.
Infection of flowers and young fruit are initially brown then become dark
and sunken. Lesions often extend through the peduncle to the succulent
stem tissue where it too takes on the characteristic dark, sunken
appearance.
Control- Hot water treatment, fungicides
8. 7.Brown spot caused by Corynespora cassiicola, Cercospora
melonis,Cercospora vignicola, Helminthosporium cassiicola,
Helminthosporium vignae,Helminthosporium vignicola
Symptoms- On the lower leaves, small, angular brown spots, often with
white centres that fall out . The spots have a characteristic well-defined
yellow halos. Oval, dark brown spots also occur on the leaf stalks.
However, in wet conditions, the spots grow much larger, join together,
and develop into spots that are zoned, or have target-like rings. Spots on
fruits are not common, but occasionally occur as dark, sunken spots on
the fruits.
Control- Remove infected papaya trees from the field, fungicide.
9. 8.Chocolate spot caused by Colletotrichum gloeosporioide
Symptoms-superficial lesions, seldom slightly sunken,
irregular to rounded, well defined, with characteristic reddish-
brown colour. As the fruit ripens the lesions can either remain
superficial or grow and become sunken, resembling
anthracnose.
Control-Remove and destroy infected plants or plant parts and
do not compost them, use resistant/tolerant varieties,
plant certified, disease free/healthy planting materials,
plant trees in well-drained soil, ensure rotations with non-host
plants, ensure proper weed control, to prevent post-harvest
losses avoid fruit wounding, i.e.
through bruising, scratching,
or puncturing the fruits,
fungicides.
10. 9.Collar rot caused by Cylindrocladium crotalariae,
Calonectria crotalariae
Symptoms-The stem of the tree will become water soaked
and weak, usually right at ground level. This water-soaked
area will develop into a brown or black lesion and begin to
rot. Sometimes a white, fluffy growth of fungus is visible. The
leaves may turn yellow and droop, and eventually the entire
tree will fail and collapse.
Control-plant papaya saplings in well-draining soil. Dig up
infected plants and destroy them, and do not plant more
trees in the same spot.
11. 10.Damping off caused by Colletotrichum
gloeosporioides,Phytophthora palmivora,Phytophthora
nicotianae,Phytophthora parasitica,Pythium
aphanidermatum,Pythium debaryanum,Pythium
ultimum,Pythium sp.,Rhizoctonia solani,Thanatephorus
cucumeris
Symptoms- seeds fail to germinate & slowly kills young
plants. The fungus eventually rots out the stem.
Control-resistant varieties, fungicide, Prepare the soil well
and ensure that it drains quickly, crop rotation, Sanitize all
containers and tools.
12. 11.Dry rot caused by Phoma caricae-papayae,Ascochyta
caricae,Ascochyta caricae-papayae,Mycosphaerella caricae
Symptoms-Fruit surface lesions are slightly sunken, circular, black .
Margins of lesions are light brown and translucent. The lesion surface
dries and wrinkles with age and turns black as it becomes covered with
hyphae and pycnidia of the imperfect stage. Under humid conditions it is
common to see light-colored tendrils of pycnidiospores oozing from
pycnidia. The infected tissue is dry, firm and is initially tan in color and
eventually turns black. Stem-end rot caused by this fungus takes on the
characteristics similar to fruit surface lesions. Infection of flowers and
young fruit are initially brown then become dark and sunken. Lesions
often extend through the peduncle to the succulent stem tissue where it
too takes on the characteristic dark, sunken appearance.
Control-Hot water treatment, fungicide.
13. 12.Foot rot caused by Pythium aphanidermatum,Pythium ultimum
Symptoms -Water-soaked patches on the stem near the ground level.
These patches enlarge rapidly and girdle the stem, causing rotting of the
tissues, which then turn dark brown or black. Such affected plants
withstand strong wind and topple over and die.
If the disease attack is mild, only one side of the stem rots and the plants
remain stunted.
Fruit if formed are shriveled and malformed. Gradually the plant dies.
Control- well-draining soil, as well as irrigation that does not touch the
trunk. Applications of copper solution shortly after planting and during
the time of fruit formation will also help.
14. 13.Fruit rot caused by Monilia sp
Symptoms-Initial fruit lesions are brown, circular, and firm.
Eventually the whole fruit decays and turns brown. Tufts of
mycelium and conidia (cream-white to buff colored) sprout
from the skin of the infected fruit, often arranged in concentric
rings. Rotted fruits may either fall to the ground or dry out on
the tree, leaving a hard, shriveled ‘mummy’.
Control-fungicides, emoval of mummified fruit and pruning
of infected twigs, with subsequent burning or deep-burying,
and the removal of wild host plants.
15. 14.Fruit spot caused by Cercospora mamaonis
Symptoms-Fruit spots start as tiny black dots that eventually
enlarge. The spots are superficial, slightly raised, a result of
the tissue beneath the epidermis becoming corky, and do not
develop into a fruit rot. The spots are somewhat obscure on
green fruits but become readily visible when the skin color
turns yellow as the fruit ripens. Actual damage to fruits is
minor except its impact on their appearance and marketability.
Control-fungicide
16. 15.Fusarium fruit rot caused by Fusarium solani,
Fusarium spp.
Symptoms-small, pitted, corky spots to large, sunken areas
covered with a white or gray mold on fruit.
Control-Crop rotations, fungicide , Avoidance of wounding
during harvest and packing, storage in dry conditions, and
proper handling during transit and marketing reduce post-
harvest decay.
17. 16.Guignardia spot caused by Guignardia sp
Symptoms- Numerous, circular to oval, sunken
greenish-black lesions expand in diameter very slowly
, the fungus may grow deep into the flesh causing a
black, firm discoloration.
Control-heat treatments.
18. 17.Greasy spot caused by Corynespora
cassiicola,Cercospora melonis, Cercospora vignicola,
Helminthosporium cassiicola, Helminthosporium vignae,
Helminthosporium vignicola
Symptoms-The leaf spots are grayish-white, subcircular to
irregular, heavily infected leaves turn yellow and dry up. The
fruit spots start as tiny spots which turn black and enlarge. The
tissue just beneath the epidermis of the fruit becomes corky;
the spot does not develop into a fruit rot.
Control-Fungicides
19. 18.Internal blight caused by Cladosporium sp.,
Fusarium sp., Penicillium sp.
Symptoms-
Infected tissue is watersoaked and translucent in the early
stages to black and firm in the later stages of infection.
Infected fruits yellow prematurely and unevenly in the fruit
column.
Control-proper seed selection, fungicides.
20. 19.Lasiodiplodia fruit rot caused by Lasiodiplodia
theobromae, Botryodiplodia theobromae, Botryodiplodia
gossypii, Diplodia theobromae, Diplodia gossypina, Diplodia
natalensis, Lasiodiplodia triflorae
Symptoms- A wider, more extensive translucent margin on fruit
,mummify the entire fruit. Gray mycelium forms over the infected area
and later turns black from the masses of pycnidia that form. The infected
flesh takes on a bluish-black discoloration in the soft water-soaked
tissue. Air pockets often form in the infected area, presumably caused by
the flesh shrinking, and later become filled with gray mycelium
Control- hot water treatment.
21. 20.Leaf spot caused by Alternaria sp., Asperisporium
caricae, Cercospora mamaonis, Cercospora papayae,
Choanephora cucurbitarum, Curvularia caricae-papayae,
Gloeosporium sp., Phoma caricae-papayae, Mycosphaerella
caricae, Phyllosticta sp.
Symptoms- irregular dark brown to black spots appear on
the lower leaf surface of leaves. On the upper leaf surface,
the infection causes slightly sunken tan spots to occur. Black
spots have also been observed on the surface of fruits.
Control- fungicides.
22. 21.Petiole spot caused by Didymella sp.
Symptoms- It causes moist dark brown stem cankers that
often develop from de-leafing and other wounds. These
lesions gradually spread and eventually surround the stem
and/or petioles, thus disrupting the sap flow. Ultimately,
yellowing and wilting of the leaflets and plant parts below the
lesions.Brownish tiny globular structures (pycnidia) dot the
damaged tissues.
Control- Long rotations with crops, Wounding fruit during
harvest and in storage must be avoided, resistant
varieties,fungicides.
23. 22.Phytophthora blight caused by Phytophthora palmivora,
Phytophthora nicotianae var. Parasitica, Phytophthora parasitica
Symptoms- Water-soaked lesions exude milky latex. Fruits may
eventually mummify and fall. Large lesions, often forming first where
the fruit contacts the stem of the plant, are covered with whitish
mycelium and masses. Fruits can rot, turn soft, and fall prematurely. As
lesions enlarge, infected areas of the stems way weaken, causing stem
damage or breaking. Foliage on affected stems may collapse. Roots may
become dark and rotten, causing stunting of plant growth and yellow,
collapsed leaves. Severely infected plants may die.
Control- well drained soil, steamed or fumigated prior to planting, hot
water treatment, Avoid damage or injury to papaya stems during
cultivation, Variety selection, fungicides.
24. 23.Powdery mildew caused by Erysiphe cichoracearum, Erysiphe sp.,
Oidium caricae, Oidium indicum, Ovulariopsis papayae, Sphaerotheca
fuliginea, Sphaerotheca humuli
Symptoms- On the undersurface of disease leaves are found patches of
whitish powder growth.
On upper surfaces, leaves at the infection site show blotches of yellow or
pale green usually near vein, surrounded by normally colored tissue.
Fungus may attack the stem of young seedling. The spots enlarge and
cover the entire leaf area. Severely infected leaves may become chlorotic
and distorted before falling. Affected fruits are small in size and
malformed.
Control-Fungicide
25. 24.Phytophthora fruit rot caused by Phytophthora capsici,
Phytophthora nicotianae var., parasitica, Phytophthora
parasitica, Phytophthora palmivora
Symptoms-Water-soaked lesions exude milky latex. Fruits
may eventually mummify and fall, fruit rot initially appears as
small, circular, water-soaked lesions. Large lesions, often
forming first where the fruit contacts the stem of the plant, are
covered with whitish mycelium and masses. Fruits can rot,
turn soft, and fall prematurely.
Control- well drained soil, pick up, remove and destroy fallen
fruits, Intercrop, steamed or fumigated, hot water, Avoid
damage or injury,fungicides.
26. 25.Rhizopus soft rot caused by Rhizopus stolonifer,Rhizopus
nigricans
Symptoms-soft and watery rot that quickly collapses the
entire fruit but leaves the cuticle intact. The fungus can grow
out through any break in the cuticle and spread rapidly to
adjacent fruits, often destroying the entire contents of a box
within a few days. The infected fruit is often covered by
coarse, gray, hairy mycelia that form a mass of black
sporangia at their tips.
Control-sanitation, use of chlorinated water tanks, wounds
should be minimized, Heat treatment, fungicide.
27. 26.Root rot caused by Phytophthora palmivora, Pythium
aphanidermatum, Pythium ultimum, Pythium spp., Rhizoctonia solani,
Thanatephorus cucumeris
Symptoms-Ripe and unripe fruit are infected while still attached to the
stem; lower fruit are infected first. Rots develop quickly and become
covered in a white growth containing spores of the water mould, causing
the fruit to shrivel and fall. Stems, also become infected through leaf and
fruit scars. Rots develop, and these cause the tops of the trees to wilt and
die. Rots also form at the base of the stem near soil level; in this case the
decaying roots are the source of infection. Roots become infected with a
soft, wet rot that affects the taproot and surface roots as well as the base
of the stem. Leaves wilt, turn yellow and collapse, with only a few small
leaves remaining at the top of the tree.
Control-Soil drainage, crop rotation, hygiene, fungicides.
28. 27.Sclerotium blight caused by Sclerotium rolfsii, Athelia rolfsii
Symptoms - development of coarse white strands of mycelium growing
in a fan-shaped pattern on lower stems, leaf litter, and soil . After 7 to 14
days, tan-to-brown, mustard-seed-sized sclerotia form on the mycelial
mat. Early symptoms consist of water-soaked lesions on crown and
lower stem tissue. The disease usually is recognized by the yellowing
and wilting of foliage, followed by a complete collapse of the plant. Soft,
water-soaked, sunken, slightly yellowish lesions develop on fruit. These
lesions quickly spread throughout most or all of the fruit, which will
eventually become soft and collapse within 3 to 4 days of infection. The
skin of the fruit often crack open and fine white mycelium and
developing sclerotia spreads over the surface and quickly fills lesion
cavities
Control-Crop rotations, selecting
fields that are free of S. Rolfsii,
Close plant spacing & over-irrigation,
Injury during cultivation should be
Avoided deep plowing, fungicide,
fumigants, Biological Control.
29. 28.Seedling blight caused by Colletotrichum gloeosporioides
Symptoms- causing cotyledon or leaf spots, defoliation, stem
lesions, collar rots, and damping-off. Over 80% of the
seedlings were diseased in 3 weeks. The fungus spread from
leaf or cotyledon lesions to stems and eventually caused stem
or collar rot and damping-off.
Control- The affected fruits should be remove and destroyed.
The fruits should be harvested as soon as they mature, hot
water treatment or a fungicidal wax treatment.
30. 29.Stem-end rot caused by Alternaria alterneta, Colletotrichum gloeosporioides,
Fusarium sp.Lasiodiplodia theobromae, Botryodiplodia theobromae, Botryodiplodia
gossypii, Diplodia theobromae, Diplodia gossypina, Diplodia natalensis,
Lasiodiplodia triflorae, Phoma caricae-papayae, Ascochyta caricae, Ascochyta
caricae-papayae, Mycosphaerella caricae, Phomopsis sp.Rhizopus stolonifer
Symptoms- A dark rot develops from the stem end as fruit ripen after harvest. A dark
brown to black rot begins at the stem end as a dark brown ring and the rot proceeds
towards the other end. The rot produces dark streaking of the water-conducting tissues
Control- fungicide, Avoid harvesting immature fruit. Cool fruit immediately after
harvest and store in well-ventilated containers.
31. 30.Stemphylium fruit spot caused by Stemphylium
lycopersici, Thyrospora lycopersici, Stemphylium
floridanum
Symptoms- fruit spot are small, round, dark brown lesions.
The lesions become sunken and develop reddish-brown to
purple margins as they enlarge. A velvety, dark green spore
mass forms in the lesion center. White to gray mycelia grow
over the lesion in the advanced stages. Internally, the infected
tissue is discolored from a reddish brown to a dark brown
color, appears dry, and small air pockets may develop.
Control- hot and cold treatments, fungicides.
32. 31.Stem rot caused by Fusarium solani, Nectria haematococca,
Fusarium sp., Phytophthora palmivora, Pythium aphanidermatum,
Pythium ultimum
Symptoms-The stem of the tree will become water soaked and weak,
usually right at ground level. This water-soaked area will develop into a
brown or black lesion and begin to rot. Sometimes a white, fluffy growth
of fungus is visible. The leaves may turn yellow and droop, and
eventually the entire tree will fail and collapse.
Control-plant papaya saplings in well-draining soil. When planting
saplings, handle them with care. Dig up infected plants and destroy them
33. 32.Target spot caused by Phyllosticta caricae-papayae
Symptoms-The spots, on the leaves, vary considerably in size, some
being small and rounded or irregular, oval, or elongated, almost white in
the centre, they are often bounded by a yellowish or brownish margin
which merges into the normal green of the leaf. The central portion of the
spots is thin and papery, and finally it becomes brittle and drops out.
When numerous spots are present, the leaf withers and falls.
Control-Removing and destroying leaves from trees infected with eye
spot, wetting foliage during irrigation should be avoided, Air circulation
may be improved by pruning and by preventing overcrowded plantings.
avoid susceptible species and cultivars , fungicide .
34. 33.Verticillium wilt caused by Verticillium dahliae
Symptoms-Sudden wilting of leaves on one or more
branches, rapid browning. Can start at base and move
upwards. Young trees may be killed. Older trees may
become stunted and lose productivity. Vascular tissue
may be stained.
Control-Avoid planting in known infected soils or
fumigate soil.
35. 34.Wet fruit rot caused by Phomopsis sp.
Symptoms- The infected area is slightly depressed, soft and translucent.
The fungus is rapid growing causing lesions to expand very quickly with
the infected area extending to the seed cavity. The cuticle over the
infected area remains intact and develops a delicate, wrinkled pattern that
is parallel to the leading edge of the lesion. Black, scattered pycnidia
usually form in the infected area after about seven days. The infected
tissue is soft, mushy and wet. The infected area can become covered by
white to gray mycelium.
Control-Removing dead and senescing leaves and petioles from the tree,
hot water treatment for 20 minutes at 48C, fungicides.