This document discusses the fungal disease Fusarium wilt or wilt of pigeonpea, caused by the pathogens Fusarium udum and Gibberella indica. It affects the important crop pigeonpea in all major pigeonpea growing states in India, causing losses of up to 50%. The disease leads to wilting, drying and death of the plant. The fungus survives in soil and plant debris and is soilborne. High soil moisture and temperatures between 20-30°C promote disease development. Management strategies include crop rotation, removal of plant debris, mixed cropping, soil treatment and use of resistant varieties.

2. Reported by butler 1910
Very common dangerous disease of pigeon pea
All arhar growing state in India (Maharastra, MP, UP,
Bihar,Tamilnadu etc.)
Loss --- 50%

3. •Fusarium udum (imperfect stage)
•Gibberella indica(perfect stage)

4. Scientific name :
• Fusarium udum BUTLER[1910]
• Gibberella indica (teleomorph) RAI
and UPADHYAY[1982]

5. 1. Symptoms appear after rainy season
2. Wilting of seedling and adult plant
3. Appear in patch
4. Drying of leaves followed by drying of entire plant
5. Black streaks several feet on the stem
6. Cortex filled with white mycelial growth

6. SYMPTOMS OF WILT OF PIGEON PEA (WILTING, DRYING, BLACK STREAK, XYLEM DISCOLOURATION)

7. The fungus is soilborne on diseased plant debris and it survives only on the tissues
which it colonizes as a parasite.
McRae reported that the fungus spreads about 3m through the soil in one season.
The amount of wilt incidence was influenced by the retentive nature of the soil, but not
directly by its water content.
Mundka reported that low soil temperature and increasing plant maturity favoured wilt.
Shukla in a pot experiment , found more wilt inoculum in sand( 94%)than in heavy ,
black soil ( 18%).
Singh and Bhargava( 1981)found the fungal population to be highest at 30% soil water
holding capacity and at soil temperatures between 20 and 30° C.
The fungus can survive on infected plant debris in the soil for about 3years.

8. Though infection may occur in the seedling stage, maximum disease occurs at
flowering and podding( Reddy et al.,1990)due to the extended time needed by the
fungus to colonize the plants.
Recent work at ICRISAT has shown that infected plants wilt only after the basal half of
the main stem is colonized by the fungus, which takes approximately 34months
(Reddy et al., 1993a).
Recent work has indicated that the fungus can survive to a depth of 120 cm in soil
(Naik, 1993).
Limited variation in the fungal population was found between the crop season and the
off season.
Inoculum placed at a depth of 100 cm was found to infect pigeon pea but did not
cause wilt. Only inoculum at 50 cm depth resulted in both infection and wilt( Naik,
1993).

9. 1.Fungi mainly confined to the vescular tissue inter and intra cellular
2.mycelium hyaline, produce 3types spore
3.Microconidia [small,elliptic.unicellular](5-15*2- 4Mm)
4.macroconidia [long,curved,pointed tip](15-50*3- 5Mm)
5.chlamydosporec[spherical,thickwall,single or in chain,terminal or intercalary]
6.perfect stage found on exposed roots and collar region of stem .mature
perithecia(350-550Mm) are superficial globous sessile,dark violet.asci subcylindrical
with 8 ovate ascospore(10*7Mm)

11.  After the discovery of the perfect state of the pathogen, two phases of the
disease cycle have been suggested : imperfect state( Fusarium udum)and
perfect state( G.indica).
 In both phases of the disease, the pathogen occurs intercellularly, intracellularly
and ectotrophically on the collar region as well as on the roots of infected plant.
 It produces a mass of mycelium and conidia.
 In imperfect state- conidia and chlamydospores serve as resting structures. l .In
the perfect state, perithecia are produced on the collar region.
 Pathogen is heterothallic.If two opposite mating types come i nto contact they
produce perithecia.Under lab conditions, perit hecia are produced at 25±2° C.

12.  Ascus contains eight ascospores (two-to three celled).
 Ascospores germinate to produce macro-and micro conidia
 Pathogen survives in infected plant,saprobic mycelium produces conidia,conidia
germinate at 1530° C under lab conditions.
 Germtubes come in contact with the pigeon pea plants, they penetrate and
colonize the xylem vessel.
 As mycelium ages, produces chlamydospore. After dormancy it germinate and
infect the roots of the plant.
 During cropping season, ectotrophic growth of the pathogen can also occur on
infected root.

14. The pathogen is a facultative saprobe, which survives on plant parts
left in the soil .Any route by which diseased soil maybe transported
from infested plot to non-infested plots, including farm implements,
irrigation water etc. ,can potentially transmit the pathogen.
Dissemination of the pathogen is also possible through seedborne
infection.

15. 1)4-5 YEAR CROP ROTATION(Tobacco,sorghum,cotton)
2)Field sanitation (removal affected plant part by deep
ploughing)
3)Mixed cropping-sorghum+arhar
4)Soil treatment –1part Formalin +400 part Water
5)Seed treatment –Benlate+Thiram
6)Desease resistance varieties: C-11;C-36;F-18;NP-
41;Pusa855;BDNI(ICP7182)

16.  Amin KS; Reddy MV; Raju TN; Nene YL; Singh RA; Zote KK; Bendre NJ; Jha DK; Bidari VB;
Naphade SD; Arjunan G; Agarwal SC; Sinha BK; Mahendra Pal; Grewal JS; Anilkumar TB, 1993.
Multilocational evaluation of pigeonpea for broad-based resistance to Fusarium wilt in India. Indian
Journal of Plant Protection, 21(1):28-30; 6 ref.
 Booth C, 1971. The Genus Fusarium. Wallingford, UK: CAB International.
 Bose RD, 1938. The rotation of tobacco for the prevention of wilt disease in pigeonpea [Cajanus
cajan (L.) Millsp.]. Agriculture and Livestock in India, 8:653-668.
 Gupta AD; Gupta PKS, 1988. Reaction of pigeonpea (Cajanus cajan) lines to wilt pathogen
Fusarium udum.. Indian Journal of Agricultural Sciences, 58(7):546-548; 6 ref.
 IPPC, 2010. First report of Fusarium udum. IPPC Official Pest Report, No. BRB-01/1. Rome, Italy:
FAO. https://www.ippc.int/
 Rai B; Upadhyay RS, 1981. Gibberella indica: the perfect state of Fusarium udum. Mycologia,
74(2):343-346(https://www.cabi.org/isc/abstract/19821384712)
 Crop Diseases And Their Management by H S Chaube And V S Pundhir ...