sclerotium rolfsii history, survival, reproduction, life cycle, management practices and case studies

1. Instructor-
Dr. R.P SinghDr. R.P Singh
Dr. Shilpi RauwatDr. Shilpi Rauwat
G.B.P.U.A.& T, Pantnagar
Presented by -
Prince Kumar GuptaPrince Kumar Gupta
Ph.D (Ag.) student
G.B.P.U.A.& T, Pantnagar

2. History………

4. Tomato infected Field…

6. Geographical distribution….
United state of
America
S. Africa
Australlia
India
Brazil
Russia Robert,P.D (2003)

7. S.Rolfsii introduction……..
 The pathogen associated with collar rot, root rot, stem rot,
crown rot or whole plant blight, wilting and damping off
 Sclerotium rolfsii is the anamorphic stage, Telomorph stage
rarely observed.
Classification
Kingdom Fungi
Phylum Basidiomycota
Class Agaricomycetes
Order Atheliales
Family Atheliaceae
Genus Athelia
Host range of S.rolfsii is so broad, at least 500 sp in 100 families are
susceptible. Legumes, crucifers and cucurbits were considered as the
most common hosts.

8. S. rolfsii culture

9. Microscopic view of S. rolfsii

10. Morphological studies… asexual stage(anamorph)

11. Morphological studies…
Asexual Stage (anamorph)

13. Morphological studies…
Sexual stage(Teleomorph)Sexual stage(Teleomorph)
BasiodosporeBasiodospore
SterigmataSterigmata
BasidiumBasidium

15. Sexual Stage (teleomorph)
• In 1926, the sexual stage of basidiomycetous fungus was first
described in Japan. The currently accepted name for teleomorph
Athelia rolfsii.
•Sexual stage not commonly seen. As in other Basidiomycetes, A.
rolfsii produces structure called a basidium in which meiosis occurs.
• Four haploid basidiospores are produced at the tips of small
structures on the basidium called sterigmata
• Athelia rolfsii produces basidia in an unprotected layer
(hymenium), which develops under humid conditions at lesions
margins. The hymenium appears as white, yellow, or buff-colored
granular with slightly wavy surface.
• The basidia are obovoid (oval shaped with one end being narrower
than the other), 7-9 microns long and 4-5 microns wide. When
mature, the basidiospores are forcibly discharged

16. Disease cycle of S.rolfsii

17. Hosts, Signs, and Symptoms
 S. rolfsii causes disease on numbers of plant species viz; field, vegetable,
fruit etc. Disease caused by S. rolfsii destructive to numerous vegetable and
fruit crops, especially tomato, pepper, melon, and watermelon
 Infection signs includes development of white strands mycelium in a fan-
shaped pattern on lower stems, leaf litter, and soil.
 Even under dry conditions, at least a trace of white mycelium should be
evident on the surface of the stem or crown. In some cases, mycelium will
be found only underground. After 7 to 14 days, tan-to-brown, mustard-
seed-sized (0.5 to 1.5 mm) sclerotia form on the mycelial mat

18.  Although symptoms vary with the host affected, infection usually restricted
to plant parts in contact with the soil. Early symptoms consist of water-
soaked lesions on crown and lower stem tissue. The disease usually
recognized by yellowing and wilting of foliage, followed by complete
collapse of the plant.
 On tomato and pepper, dark water-soaked lesions on the lower stem at or
near the soil surface are present and rapidly develop to completely girdle
the stem Infection of cucumber and watermelon is normally restricted to
fruit lying in contact with the soil.
Fruits rot

19. • Lower stem decay develops, plants usually remain erect and foliage
wilts. On many host plants, wilted leaves gradually become brown
and remain hanging on the plant (Pattmark et al., 1996)
•Sclerotia serve as overwintering bodies and may be seen in the
mycelium, on diseased tissues above or below ground or on soil
surfaces.
• Lower stem decay develops, plants usually remain erect and foliage
wilts. On many host plants, wilted leaves gradually become brown
and remain hanging on the plant (Pattmark et al., 1996)
•Sclerotia serve as overwintering bodies and may be seen in the
mycelium, on diseased tissues above or below ground or on soil
surfaces.
Lower stem rot symptoms

20. • On some plants, such as tomato, pepper, and sweet potato, root
infection may follow crown infection (Bowen et al., 1992)
• On apples, roots are the primary infection site and crown rot
develops subsequently.
• Usually the characteristic white mycelia mat and sclerotia develop
near and on infected crown tissues or in and around roots close to
the soil surface
• The leaves eventually die and branch die back develops.
Root Decay symptoms

21. Survival

26.  Select field that are free of S. rolfsii
 Deep plowing at depths below 20-30 cm, sclerotia do not survive longer than 45 days.
Weed control must be maintained during rotations to prevent inoculum increase
Crop rotations with non-host crop like corn or small grains prevent diseases.
(Robert, P.D 2014)
 Staking plants prevent fruit from
touching the ground.
 Avoided rotations with peanuts,
soybeans, cabbage, and carrots.
 Black plastic mulch and row covers
provides barrier between fruit and soil.
 Soil pH at 6.5 by addition of lime help to
prevent fungal growth. CULTURALCULTURAL

28.  Aeration of the soil and removal of thatch or other plant debris will also aid
in suppressing S. rolfsii growth (Bowen et al., 2010).
 Close plant spacing and over-irrigation promote disease development
avoided.
 Six tomato breeding lines—5635M, 5707M, 5719M, 5737M, 5876M, and
5913M—resistant to Sclerotium rolfsii were released jointly from Texas A&M
University Research Center, Coastal Plain Experiment Station and the
University of Georgia. ( Leeper , P.W)
 Grafting tomato plants onto interspecific hybrid rootstocks has also
been successful in managing disease

30. • In some large nurseries or
greenhouses, it may be
possible to treat beds or
bulk soil with aerated
steam.
• All areas must be brought
to a temperature of 160-
180o
F for 30 minutes.
Treated soil should be
stored away from
contaminated areas.
• Even after steam
treatment, some sclerotia
may survive and losses may
occur.
Heat

31. Soil solarization

32. • Sclerotia grown in vitro are still viable after 12 hours at 450
C,
but are killed in 4-6 hours at 50ºC and in 3 hours at 55ºC .
• Covering soil with transparent polyethylene sheets during the
hot season increases soil temperatures and kills sclerotia.
• Field trials have achieved sclerotia degradation at 1 cm, but
eradication at greater depths usually did not occur. This
method requires immediate planting, which excludes crops
that are planted in spring because temperatures are not high
enough to affect sclerotia.
• Soil solarization combined with the addition of Trichoderma
harzianum has been shown to decrease disease incidence more
than either treatment alone. (Kator et al. 2015)

33. 33

34.  Compost, oat, or straw added to the soil has been shown to limit
disease incidence. The addition of an amendment may increase
populations of antagonistic soil microorganisms.
 This effect may be due to the increase of toxic ammonia and/or the
increase of certain soil microorganisms in the soil.
 An organic (sugar derivative) amendment, has been shown to
change the soil microflora, and this change has been related to a
decrease of S. rolfsii in the soil in lab and greenhouse studies.
 Neem oil and pine bark extracts or pine bark powders have resulted
in reduced growth of S. rolfsii.
Amendments:

35. Organic
extracts
Average dia. of
pathogen (mm)
after 5 days
Growth
inhibition
(%)
No. of
sclerotia/plate
after 10 days
Mustard cake 8.77 11.83 302.33
Castor cake 8.66 14.12 271.67
Neem cake 7.68 32.44 186.00
FYM 8.01 26.34 200.0
Press mud 8.62 14.89 262.00
Poultry manure 8.70 13.36 280.33
Control 9.34 - 390.20
S.Em (±) 0.12 - 6.36
c.v 2.14 - 4.09
Mean of three replications P.D. Madhukarrao, 2013

36. Biological control
 Along with species of Trichoderma,
other biological agents, such
as Gliocladium virens, Bacillus subtilis,
and Penicillium spp., were found to
antagonize S. rolfsii and help in
disease suppression.
 Gliocladium virens reduce number of
sclerotia in soil to a depth of 30 cm
 Trichoderma koningii reduced
sclerotia number in tomato fields
 Recently, isolate of Streptomyces
philanthi found effective against S.
rolfsii in chilli. (Boukaew et.al
20.11)

37. Biocontrol agents Average dia. of
pathogen (mm)
Growth
inhibition (%)
Trichoderma viride 5.97 35.93
Trichoderma harzianum 5.48 46.11
T. Koningii 6.30 28.74
Pseudomonas
florescence
5.77 40.12
Bacillus subtallis 6.40 26.35
Control 7.46
S.Em (±) 0.07
c.v 1.83
Mean of three replications P.D. Madhukarrao, 2013

38. Chemical control
Hexaconazole, tabuconazole can be
used @ 1ml/ ltr
Fosetyl Al @ 2gm/ltr
Mancozeb @ 2 gm/ltr
Copper oxy chloride @ 3gm/ltr
Carbendazim @ 1gm/ltr
Thiophanate methyl @ 1g/ltr
(Rakholiya.
2015)

40. Conclusion…..
S. Rolfsii described by Saccardo and pathogen having
broad geographical distribution & having wide host range.
Mycelium, white, hyaline hyphal having clamp connection.
Four haploid basidiospores on basidium
Sypmtoms, white strand mycelium, fan shaped pattern
on plant parts
Management practices, its protect the plant from various
diseases.
pH, acidic for mycelia and sclerotia germination 3.0-5.0 and
2.0-5.0 respectively.
Temperature, mycelial growth 25-35°C

41.  Roberts, P. D., French-Monar, R. D., and McCarter, S. M. 2014. Southern Blight. Pp. 43-44 in:
Compendium of Tomato Diseases, 2nd edition, Jones, J. B., Zitter, T. A., Momol, M. T., and Miller,
S. A. (eds.). APS Press. St. Paul, MN.
• Xie, C., and Vallad, G. 2010. Integrated Management of Southern Blight in Vegetable
Production. Publication #PP272. Florida Cooperative Extension Service.
• Leeper, P. W., Phatak, S. C., and George, B. F. 1992. Southern blight-resistant tomato breeding
lines: 5635M, 5707M, 5719M, 5737M, 5876M, and 5913M. Hortscience 7:475-478.
• Fery, R. L., and Dukes, P. D. Sr. 2005. Potential for utilization of pepper germplasm with a
variable reaction to Sclerotium rolfsii Sacc. to develop southern blight-resistant pepper
(Capsicum annuum L.) cultivars. Plant Genetic Resources 3:326-330.
• Rivard, C. L., O’Connell, S., Peet, M. M., and Louws, F. J. 2010. Grafting tomato with inter-
specific rootstock to manage diseases caused by Sclerotium rolfsii and southern root-knot
nematode. Plant Dis. 94:1015-1021.
• Bulluck, L. R., III, and Ristaino, J. B. 2002. Effect of synthetic and organic soil fertility
amendments on southern blight, soil microbial communities, and yield of processing tomatoes.
Phytopathology 92:181-189.
• Ristaino, J. B., K. B. Perry, and R. D. Lumsden. 1991. Effect of solarizaton and Gliocladium
virens on sclerotia of Sclerotium rolfsii, soil microbiota, and the incidence of southern blight of
tomato. Phytopathology 81:1117-1124.
REFERENCES

42. • Latunde-Data, A. O. 1993. Biological control of southern blight disease of tomato caused
by Sclerotium rolfsii with simplified mycelial formulations of Trichoderma koningii. Plant
Pathology 42:522-529.
• Boukaew, S., Chuenchit, S., Petcharat, V. 2011. Evaluation of Streptomyces spp. for biological
control of Sclerotium root and stem rot and Ralstonia wilt of chili pepper. BioControl 56:365–
374.
• Roberts, P. D. 2003. Southern Blight. Pp. 20-21 in: Compendium of Pepper Diseases,
Pernezny, K. L., Roberts, P. D., Murphy, J. F., and Goldberg, N. P. (eds.). APS Press. St.
Paul, MN.
• Bruton, B. D. 1996. Southern Blight. Pp. 56 in: Compendium of Cucurbit Diseases, Zitter, T.
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Laboratory, ARS, USDA. Retrieved March 14, 2014, from
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• K. B. RAKHOLIYA. 2015. SCREENING OF FUNGICIDES AGAINST SCLEROTIUM ROLFSII
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• P.D.Madhukarrao.2013.management of foot rot (sclertotium rolfsii (Sacc.) of finger
millet.department of plamt pathology N.M college of gujrat.
• Rivard, C. L., O’Connell, S., Peet, M. M., and Louws, F. J. 2010. Grafting tomato with inter-
specific rootstock to manage diseases caused by Sclerotium rolfsii and southern root-knot
nema-tode. Plant Dis. 94:1015-1021.