Fusarium wilt banana

PAT 401

1. COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 Fusarium Wilt of Banana Submitted by Course Teacher K.S.ANUPRIALASHMI Dr.S.PARTHASARATHY ID. No. 2015021012 Asst.Prof .,(Plant Pathology)

2. Scientific classification Kingdom: Fungi Division: Ascomycota Class: Sordariomycetes Order: Hypocreales Family: Nectriacea Genus: Fusarium Species: F.  oxysporum

3. HISTORY & DISTRIBUTION Fusarium oxysporum f.sp .cubense is a soil-borne fungus that causes Fusarium wilt, which is considered to be the most destructive disease of bananas. The fungus is believed to have evolved with its host in the Indo-Malayan region, and from there it was spread to other banana-growing areas with infected planting material.

4. LIFECYCLE

5. Symptoms: Externally, the first obvious signs of disease in most varieties are wilting and a light yellow colouring of the lower leaves, most prominent around the margins. They eventually turn a bright yellow colour with dead leaf  margins. Splitting of pseudostem base is a characteristic symptom.

6. Internally, symptoms first become obvious in the xylem (water conducting) vessels of the roots and the rhizome. These turn a reddish-brown to maroon colour as the fungus grows through the tissues. When a cross-section is cut, the discolouration appears in a circular pattern around the centre of the rhizome where the infection concentrates due to the arrangement of the vessels. As symptoms progress into the pseudo-stem, continuous lines of discolouration are evident when the plant is cut longitudinally

7. Identification of pathogen: The casual organism is  Fusarium oxysporum f.sp .cubense . This pathogen contains colonies of white to purple pigemented mycelium. Hyphae are septate and hyaline.  Conidiaphores are short and simple and having macroconidia and microconidia Macroconidia usually produced abundantly, slightly sickle-shaped, thin-walled, with an attenuated apical cell and a foot-shaped basal cell. They are three to 5-septate measuring 23-54 x 3-4.5 µm.      

8. Microconidia are abundant, mostly non- septate , ellipsoidal to cylindrical, slightly curved or straight, 5-12 x 2.3-3.5 µm occurring in false heads  from short monophialides . The disease is soil borne and the fungus enters the roots through the fine laterals. The incidence is high in acid alluvial soils. The pathogen is easily spread by infected rhizomes or suckers, farm implements or vehicles, irrigation water

9. MANAGEMENT : Cultural method Practice proper crop rotation with paddy/sugarcane once or twice followed by banana for 2-3 cylces Plant wilt resistant cultivars  such as Poovan and Nendran in endemic areas Proper care should be given when planting susceptible cultivators such Rasthali , Monthan , Karpuravalli , Kadali , Pachanadan by selecting healthy suckers from disease fields Remove and destroy infested plant material after harvest

10. When only 1-3 plants are infected, kill and chop up the diseased plants and stew all the material in water at a temperature of at least 70 deg C for 30 minutes. Grow healthy plants with proper fertilization, irrigation, weed control Provide good drainage especially during rainy season Soil application of rice chaffy grain or dried banana leaf formulation or well decomposed compost around the plants 

11. Mechanical method Machinery and equipment should be treated with a  sanitary solution such as Farmcleanse ® Footwear, which may have contacted banana plants or soil around banana plants elsewhere, should not be worn on the farm. Provide mechanical barriers in and around the infected plants Biological method Application  Pseudomonas fluorescens @ 2.5kg/ha bactericide can also be applied along with farmyard manure and neem cake. About 60 mg of Pseudomonas fluorescens (in a capsule) can be applied in a 10 cm deep hole made in the corm.

12. Application of bio control agents like  Trichoderma viride  @ 25 g for 4 times once at the time of planting in the planting pit and remaining doses at third, fifth and seventh month after planting Application of  T.harzianum  Th-10, as dried banana leaf formulation @ 10g/ platn in basal + top dressing on 2,4,and 6 months after planting

13. Chemical method Application of 2 per cent of Carbendazim as injection of Carbendazim 50 ml capsule application Paring ( pralinge removal of roots and outer skin of corm) and dipping of the suckers in clay slurry and sprinkled with Carbofuran granules at 40g/corm Soil drenching of Carbendazim 0.2 per cent solution alternated with Propiconozole 0.1% around the pseudostem at bimonthly intervals starting from five months after planting Application of urea + sugarcane trash (250g/pit) followed by lime (1Kg/pit) and neem cake (1-2Kg/pit) Application of neem cake @ 250 Kg/ha was most effecgtive in controlling Fusarium wilt in Rasthali cultivar

14. Symptoms: www.tnauagriportal.com

15. Isolation of Fusarium oxysporum f.sp. cubense

16. Conidia of Fusarium oxysporum f.sp . cubense

17. References: Gupta V.K and Paul V.S 2004. Fungi and Plant diseases. Kalyani Publishers. New Delhi. www.ucmp.berkely.edu/fungi