Plant Pathology

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po), ViaVaigai Dam, Theni - 625 562
GUAVA WILT
COURSE TEACHER STUDENT
Dr. PARTHASARTHY. S NAME : C. GOKILA
Asst. Professor (Plant Pathology) ID.NO : 2015021038

2. GUAVA WILT
• Fusarium oxysporum f.sp. psidii (Prasad et al 1952)

3. Occurrence
History
• The disease was first noticed in 1935 in Allahabad.
• It spread to more than 20,000 sq. miles during 1952.

4. Geographical distribution
World
• Guava wilt has been reported in Taiwan (Hsieh et al),
South Africa (Grech and Frean), Brazil (Tokeshi et al),
Pakistan (Ansar et al) and Reunion island (Normand).

5. Geographical distribution
India
• Guava wilt reported in the different part of Uttar Pradesh,
West Bengal, Haryana, Punjab, Bihar, Delhi, Andhra
Pradesh, Gujarat, Maharashtra and Madhya Pradesh.

6. Significance
Economical
• Reported, 5-20 % trees killed in annually in Allahabad,
Lucknow and Faridabad.
• In West Bengal the wilt caused reduction of the yield upto
80%.

7. Significance
• In Andhra Pradesh land value reduced to half due to wilt
disease.
• 150 acres of the wilt affected guava orchid in Punjab.
• 300 acres in Haryana were uprooted in 1978-1981.

8. Symptoms
• First external symptom of
the guava wilt is the
appearance of yellow
colouration with slight
curling of the leaves on
terminal branches.
©http /www.agriverge.in

9. • Subsequently browning,
drooping and pre-mature
shedding of the leaves
occur.
• Generally the symptoms
appears after the rains. ©http://www.forestyimage.org

10. • That is during October - November when the fruits are small.
• The wilt affected branches fruits remain under developed, hard
and stony.

11. • Usually fifteen days are required
for the complete wilting.
• Some trees take even up to one year.
• Light brown discolouration is also
noticed in the vascular tissues.
©http://www.invasine.org

12. Pathogen
• Das Gupta and Rai reported the association of Fusarium sp
with the wilt disease in U.P.

13. Systematic position
Kingdom : Fungi
Phylum : Ascomycotina
Subphylum : Peziziomycotina
Class : Sordariomycetes
Subclass : Hypoceromycetidae
Order : Hypocereales
Family : Nectriaceae
Genus : Fusarium
Species : oxysporum

14. Pathogen characters
• Mycelium is white or pink with a
purple tinge.
• Pathogen produces microconidia,
macroconidia and chlamydospores.
©http://www.researchgate.net

15. • Microconidia are single celled, hyaline elliptical shape.
• Macroconidia are sickle shaped, hyaline, 3-5 septate and tapering
at both ends.
• Chlamydospores are thick walled, spherical to oval, hyaline to
slightly yellowish in colour.
©http://www.researchgate.net

16. Life cycle
©http://www.agronomie.info

17. Survival and spread
• It is soil borne pathogen. Survives in soil as chlamydospores for
longer periods.
• The primary spread of the disease by the affected soil.
• Secondary spread by water.
• Root injury predisposes wilt disease.

18. Favourable conditions
• High rainfall during August/ September.
• Stagnation of water in guava field for long duration.
• Maximum and minimum temperature ranges 23-32○C with 76% RH
are conducive.
• Lack of timely application of suitable control measures.

19. Integrated disease management
• Cultivate the resistant varieties of Banarasi, Dholka a Sind,
Nasik white guava, Supreme and Lucknow 96.
• Pruning and burning the affected twigs.
• Application of green manure and oil cake.

20. • Spread of the wilt could be checked by judicious amendments
of N and Zn.
• The wilt was reported to be controlled by soil treatment with
1.82 kg lime or gypsum / tree.

21. • Biocontrol agents Trichoderma sp and Streptomyces
chibaensis have been suggested for the control of wilt
pathogens.
• Soil drenching with Carbendazim 0.2% at 4 times in a year.

22. References
• Tripathi.D.P. 2009. Crop diseases. Kalyani publishers. New
Delhi. Pg.No :164.
• Saha.L.R. 2002. Hand book of plant diseases.Kalyani
publishers. New Delhi. Pg.No : 299.
• Thind.T.S. 2001. Diseases of fruit and vegetables and their
management. Kalyani Publishers. New Delhi. Pg.No : 124.
• www. agrivilage.in