A brief note on crop disease by Ram kumar Shrestha for BSc agriculture student based on syllabus of IAAS.

1. R a m K u m a r S h r e s t h a

2. Syllabus
Sixth semester 2015, B.Sc. Ag, IAAS Lamjung
Instructor: Asst. Prof. Ram Kumar Shrestha
Office Location: Central lab
Office hours: Monday & Friday, 11:00 am to 1:00 pm
Telephone:
Office: 066-402038/Personal: 9845026185
Email: ramkuma.shrestha@mail.huji.ac.il/meroramu@hotmail.com
Course Title:
Crop disease and their management
Course Code: PLP 321
Credit hours: 3 (2+1: 2 hours of theory and 1 hour of field work)
Prepared by R. K. Shrestha

3. Syllabus con…
Course description:
! The course covers etiology, conducive factors, symptmatology, disease cycle and integrated
management aspects of major disease of common agricultural plants.
Prerequisites:
! Students should have completed the fifth semester of B. Sc. Ag.
! Learning Outcomes:
! After the completion of this students will be able to Understand the etiology, symptmatology, disease cycle and
integrated management aspects of major disease of common agricultural plants and related terminologies.
! After the completion of this students will be able to Understand the disease specific mechanisms of symptom
development.

4. Syllabus con..
Books:
! Crop Disease and their Management- H.S. Chaube & V.S. Pundhir
! Plant Pathology – B.P. Pandey
! Plant Pathology- G.N. Agrios
! Plant Pathology- R.S. Mehotra
Class schedule will be notified to all of you via. Class Representative
Students are suggest to visit this page:
http://www.dpi.nsw.gov.au/aboutus/services/collections/scientific-
illustrations/senior

5. Regulations to follow in class:
Regulations: Consequences:
Use of mobile in class is prohibited First time warning, second time out of
class.
Foods are not allowed in class Out of class.
Side talks are strongly prohibited First time warning and from next time
his/her grade will be deducted
Sleeping in class can’t be tolerable First time warning, second time out of
class.
Late comers after 15 are restricted No entry
80% Attendance on class is necessary No Internal Assessment
No late submissions of assignment Will not be evaluated
Lab rules should be followed strictly First time warning, second time out of
lab.
Any other violation or cheating Situational decision of instructor will
be valid

6. Introduction to Plant
Pathology (5th Sem.)
Brief revision
Prepared by R. K. Shrestha
Biology Terminologies

7. R a m K u m a r S h r e s t h a

8. Name of Disease e.g.- XYZ
! Etiology (causal agent/incitant)
! Fungal
! Bacterial
! Viral
! Symptomatology
! Signs, Symptoms & Syndromes (blight /blotch/leaf spot/shot hole/wilt/shoe stinging/mosaic/
chlorosis/necrosis/wart/ downy mildew/powdery mildew/gall)
! Epidemiology & Disease cycle
! Environmental factors
! PSI/SSI – Site of entry
! Survival structures (resting mycelium/cleistothesia/ collateral & alternate host)
! Management & Control
! Exclusion of SI (seed treatment/summer plough/sanitation/vector control)
! Use resistant varieties
! Cultural practices
! Botanicals and antagonistic organisms
! Use chemicals (Systemic/contact)
Biology & reproduction
Class
Order
Family

9. Powdery Mildew (PM)
Causal organism is an obligate biotrophic parasite of phylum ascomycota of kingdom fungi
Widely distributed all over the world, characterized by the production of powdery
fungal mass on the aerial parts of the host and causes defoliation.
खरा$ रोग

10. Powdery Mildew (PM)
Causal organism is an obligate biotrophic parasite of phylum ascomycota of kingdon fungi
Widely distributed all over the world, Characterized by the production of powdery
fungal mass on aerial parts of the host and causes defoliation.
खरा$ रोग

11. Powdery Mildew of Pea
Etiology: Erysiphe polygoni (Ectophytic-Obligate parasite)
Ascomycota
Erysiphales
Erysiphaceae
Early detection is necessary for effective chemical control
F…

12. PM of Cucurbits
Etiology: Podosphaera xanthii & E. cichoracearum (Obligate parasite)
.
Ascomycota
Erysiphales
Erysiphaceae

13. PM of wheat
Etiology: Blumeria graminis f.sp. Tritici (Syn. E. graminis f.sp. Tritici)-Obligate parasite
More on hills than Terai
Ascomycota
Erysiphales
Erysiphaceae

14. PM of Apple
Etiology: Podospheroera leucotrica (Obligates)
Netting
Ascomycota
Erysiphales
Erysiphaceae
Upto 100% yield loss has been reported (Chee & Wurms, 2011)
N

15. Downy Mildew (DM)
" Causal organism biotroph of class oomycetetes of
kingdom fungi
" Major genus involved in this disease: Plasmopara,
Perenospora, Pseudoperonospora, Sclespora,
Scleropthora, Peronosclerospora
" Variable symptom, mostly production of
cottony downy fungal mass on adaxial part with
tan spot on upper side of leaf of the host and
causes defoliation. In stem it produces shrunken
lesions which later on filled with cottony growth

16. DM of Grapes
Etiology: Plasmopara viticola (Obligate-Intercellular)
Netting
Destructive disease mostly attack tender parts
Oomycota
Peronosporales
Peronosporaceae

17. DM of Cucurbits
Etiology: Pseudoperonospora cubensis (Obligate biotroph) i
Oomycota
Peronosporales
Peronosporaceae

18. DM of Crucifers
Oomycota
Peronosporales
Peronosporaceae
Etiology: Perenospora parasitica (Obligate, endophyute)

19. DM of Maize
Etiology: Scleropthora macrospora (-Crazy top DM)
Sclerophthora rayssiac var. zeae (Brown spripe DM)
Peronosclerospora philippinensis (Philippine DM)
Oomycota
Peronosporales
Peronosporaceae

20. Damping off of seedlings
Various
Wire stem

21. Root rot/collar rot/Gumosis of citrus
Phytopthora citropthora/ P. parasitica/ P. palmivora/ P. syringae/ P. hibernalis
P. cactorum/ Fusarium
Various

22. Root rot/collar rot of Papaya
Various

23. Root rot/collar rot of Jute
Causal agent: Macrophomina phaseoli (Pycnidial) & R. Solani (Sclerotia)
Seed and debries
Pycnidia and sclerotia
Crop rotation / NPK
Seed treatment
PCNB/ benomoyl/Bavistin
Deuteromycetes
Sphaeropsidales
Sphaeropsidaceae

24. Sori containing fungal spores on aerial part
of plant
Pustules of spores usually breaking through host
epidermis, dusty or compact, red brown, yellow
or black in color
Causes defoliation, increase in transpirational
water
loss
Loss of photosynthetic area
Poor grain fill and results in shriveled grains
Different besidiomycetes fungi are responsible for this disease
Major are, Puccinia, Uromyces, Hemileia etc

25. The most common rusts diseases are
Stem rust or black rust
(Puccinia graminis f. sp. tritici),
Leaf or brown rust
(Puccinia recondita).
Stripe or yellow rust
(Puccinia striiformis tritici)
Rust of wheat
Biotrophic, Obligately parasitic, Basidiospores not
contained within Basidiocarp (5 possible spore types)
Basidiomycetes
uredianales
Pucciniaceae
www.ars.usda.gov/Main/docs.htm?docid=9757

26. 0 Spermogonia
3 Telia 2 uredia
1 aecia
4 Basidia General scheme
Lifecycle of Puccinia

27. Rust of wheat
Stripe rust Stem rust Leaf rust

28. Rust of wheat
Particular Stem rust Brown/leaf Yellow /stripe
Affected sites Terai Foot Hills/ inner terai Midhills
Major occurance March –April Feb-March Jan- Feb
Alternate host Barbery Thalictrum spp./Anchusa sps. NA
Collateral host Aegilops, Agropyron,
Bromus
Aegilops, Agropyron, Bromus Aegilops, Agropyron, Bromus
Nature Macrocyclic Macrocyclic Hemi cyclic
Resistant wheat var Vijaya, BL3503,
BL3235
Achyut, Rohini BL-1473, Gautam WK 1204, WK1123 BL1813,
NL 297, Passang lahmu

29. Rust of wheat

30. Rust of Pea
Teleutopustules
Uredialpustules/ sori on both sides
Broad bean/ lentil also affecetd
Teliospore- 1celled besidium=4 sporidia
Basidiomycetes
uredianales
pucciniaceae

31. Rust of Bean
Wide spread in Moog and French bean
Attack mostly leaf
Basidiomycetes
Uredianales
Pucciniaceae

32. Loose smut of wheat Basidiomycetes
Ustilaginales
Ustilaginaceae
Disease of hills and terai
Internally seed borne followed by systemic infection
http://ohioline.osu.edu/ac-fact/0012.html

33. Fig: Life cycle of Ustilago tritici

34. Hill/Common/Stinking Bunt
of wheat
Tilletia tritici ®/ T. lavis
Symptoms only on ear head
Ripen earlier than normal
Affected ear dark green
Basidiomycetes
Ustilaginales
Tilletiaceae
Externally seed borne followed by systemic infection
The disease is ranked second after rusts in world-
wide importance (Hoffmann 1982; Wiese 1987).

35. Fig: Life cycle of Telitia caries

36. Karnal/partial Bunt of wheat
Causal agent: Tilletia indica (braclayana)
Pathogen survival:
Externally seed born/SOIL
Remains in soil for 3-5 years
Seed treatment (water/salt-hot water/fungicide-solarization) Naocl
Resistant varieties; Kalyan sona, HD 2012,
Infected head destruction
Crop rotation
Foliar spray of PCNB, Bavistin and DM-45 @ 0.2% or Hexaconazole
0.1% on anthesis
Q
Externally seed borne followed by partially-systemic infection
Basidiomycetes
Ustilaginales
Tilletiaceae
[syn. Neovossia indica (Mitra) Mundkur]

37. Covered smut of barley
Causal agent: Ustilago hordei
Disease of hill and terai
Pathogen survival:
Seed born/soil
Management:
Seed treatment – Thiram/tilt/ agrosan GN, Vitavex
Smutted head destruction
Crop rotation
Resistant varieties: K-12, EB 4003, BHS 4, C-85.
Externally seed borne followed by systemic infection
Basidiomycetes
Ustilaginales
Ustilaginaceae

38. Wilt of Guava
Highly destructive disease which appears to be a wilt complex of fungal invasion, insect attack and nutritional disorder.
Affected plant becomes lusterless in rainy season
Browning and wilting of plant can be observed
Discoloration and death of branch can be seen
Some time whole plant turns dead
F. Oxysporu f. sp. psidii
Duteromycetes
Moniliales
Tuberculariaceae
..

39. Wilt of cotton
Fusarium oxysporum f.sp. vasinfectum
Can affect at all stage
Chlorosis- leaf drop- starting from lower leaf
Internal discoloration proceed upward
Xylem filled with fungal hyphae
Duteromycetes
Moniliales
Tuberculariaceae

40. Wilt of lentil & chickpea
Fusarium oxysporum f.sp. Lentis & ciceri
Generally appears 20 das
Chlorosis- leaf drop- starting from lower leaf
Internal discoloration proceed upward
Xylem filled with fungal hypha
Soil borne/seed borne
Wounds and nematode foster penetration through root hairs
Production of fusaric acid and tylose
Cultural : (debris disposal, crop rotation, mix with Barseem, summer plough)
Application of FYM and T. harzianum
Seed treatment & Reistant varieties: ICC 858, 959,9001- chickpea
DM-45@ 0.2% (10-15 days repeat)/ Benomyl + thairam 1:1
Duteromycetes
Moniliales
Tuberculariaceae

41. Late blight of potato
Phytopthora infestans
Dormant mycelium in tuber/debris
Oospore has been reported
Cultural: hulm cutting and field sanitation
Tuber selection/Tuber treatment (carbendazim 1gm+Mancozeb 2gm/HgCl2)
Resistant variety: Janak Dev, Kufri Jeevan, Kfri Alankar, Kufri Giriraj
DM-45@ 0.2% (7-10 days repeat), Rijemil/Krinoxil 72%WP @ 0.15%
Blitox-50 prophylactic spray from 6wap
Trichoderma
Oomycetes
Peronosporales
pythiaceae

42. Late blight of Tomato
Phytopthora infestans
Debris /seed
Oospore has been reported
Cultural: healthy management
Seed selection/seed treatment (carbendazim 1gm+Mancozeb 2gm)
Resistant variety: Iron lady, lemon drop, Mountain magic, Mountain merit
DM-45@ 0.2% (10-15 days repeat)/kripkxil/krinokcil prophylactic spray from 6wap
Trichoderma
Oomycetes
Peronosporales
pythiaceae

43. Mango malformation
Causal agent: Different views 1. Physiological
2. Acarological (Aceria mangiferae)
3. Viral
4. Fungal (Fusarium moniliformi var subglutans)

44. The vegetative malformation generally
affects seedlings of young plants in
which there is swelling of buds.
Normal leaf bud
Distorted leaf bud
It leads to formation of small cluster with
short internodes at the apical portion and
give an appearance of witches broom
like structure.
Mango malformation

45. Mango malformation

46. Mango malformation
Fusarium moniliforme var. subglutans
Nursery seedlings
Micro conidia-SSI carried by mites
Clean planting materials : use certified nursery stocks
Sanitation: disposal of infected parts
Resistant variety: Langra (less affected)
Spray of napthalic acetic acid (NAA) @ 100-200 ppm in October followed by
Deblossming at bud burst stage
Fungicidal spray: Bavistin or Benlate @ 0.1-0.2%
Duteromycetes
Moniliales
Tuberculariaceae

47. Blast of rice
Pyricularia oryzae (Tel. M. grisea)
Seed borne/air borne/Dormant mycelium in debris
Chlamydospores / collateral host
Cultural: Healthy management with stagnant water
Reduce nitrogen level, P. fluorescens
Seed selection/seed treatment (Carbendazim/Thiram/Agrosan 2gm)
Resistant variety: Sabitri, Janaki, Laxmi, Makwanpur-1, IR 579
Tricyclazole 75%WP @ 0.075%, Kasugamycin 3% @ 0.15%,
Hinosan-50 EC (1-2l/ha)/
Deuteromycetes
Moniliales
Moniliaceae

48. Brown spot of rice
Helminthosporium oryzae(Tel. Cochliobolus miyabeanus)
Seed borne/Dormant mycelium in debris
collateral host
Cultural: healthy management
Seed selection/seed treatment (Bavistin/Thiram 2gm/kg)
Resistant variety: IR 24, Padma
Mancozeb (1-2kg/ha), Hinosan-50 EC (1-2l/ha), Benlate (1-2kg/ha)
Deuteromycetes
Moniliales
Dematiaceae

49. Leaf spot of crucifer
Alternaria brassicae/ A. alternata/ A. brassicicola
Seed borne/Soil borne
Volunteer host
Cultural: crop rotation/sanitation
Seed selection/seed treatment (Hg compound)
Nutrient management
Resistant variety: Pusa Kranti, Seeta, RW 351- Mustard
Zineb (0.2%), DM 45, Blitox-50, DM-45
Deuteromycetes
Moniliales
Dematiaceae

50. Tikka disease of groundnut
Cercospora arachidcola (Tel. Mycospherella. arachidis)
C. personata (Tel. M. berkleyii)
Seed borne/Plant debris
Volunteer host
Cultural: healthy management
Seed selection/seed treatment (Bavistin/Thiram 2gm/kg)
Apply potassium and magnesium
Early maturing varieties
Moderately resistant varieties: ICGV920920, ICGV92093
Blitox -50 (0.8 Kg/acre), Spray Bordeaux mixture (2:2:50)
Deuteromycetes
Moniliales
Dematiaceae

51. Leaf spot of chilli
Cercospora capsicae (T. M. sps.)
Seed borne/Survival on debris
Enters through stomata
Cultural: Sanitation
Seed selection/seed treatment (Bavistin/Thiram 2gm/kg)
Resistant variety: Small fruit cultivar
Mancozeb (1-2kg/ha), Hinosan-50 EC (1-2l/ha), Benlate (1-2kg/ha)
Bordeaux, Mineral oil
Deuteromycetes
Moniliales
Dematiaceae

52. Anthracnose of bean
Seed borne/Soil borne
Volunteer host
Cultural: crop rotation/sanitation
Seed selection/seed treatment (Benomyl 17%, Ziram/thiram@ 5g/kg)
Resistant variety: Negro, IAPAR Rio.
Benomyl 0.55g/lt, zineb @ 0.35%, captafol 3.5kg/ha, carbendazim 0.5kg/ha
Deuteromycetes
Melanconiales
Melanconiaceae
Colletotrichum lindemuthianum (T. Glomerella cingulata)

53. Die Back/Fruit rot of chilly
Colletotrichum capsici (T. Glomerella .) H-biotroph
Seed borne/Survival on debris
SSI: conidia disseminated by wind and rain
Cultural: Sanitation
Seed selection/seed treatment (Captan/Thiram 2gm/kg)
Resistant variety: Lorai, perennial
DM-45 0.2%, Blitox-50, Zineb, perenox
Pseudomonas fluorescence/azotobacter
Deuteromycetes
Melanconiales
Melanconiaceae

54. Stem Gall of Coriander
Protomyces macrosporous
Chlamydospore (3 layered)
Soil/seed Borne
Cultural:
Seed Treatment: Thairam/soil
healthy management
Thiram @ 20 Kg/ha>Carboxin>Captafol
Ascomycota
Taphrinales
Protomyceteceae

55. Peach leaf curl
Taphrina deformans
(ascospore are PSI-blastospore)
Cultural: healthy management
Resistant variety: World’s Earliest, Escape the cool, July Elberta
Timely spraying of BM, Chlorothalonil, Blitox-50 0.2%, Calixin, 0.05% Perenox
Ascomycetes
Taphrinales
Taphrinaceae
Young and tender parts are susceptible
Can attack leaf, twigs and fruit
Distortion of fruit can be seen