Wilt
Causal organism: Verticilium albo-atrum
Symptoms
Aerial symptoms:
- Initially lower leaves starts V shape yellowing. Dwarfing unilateral development of the branches. Etiolating of leaves leading to wilting death.
Internal symtoms:
- Light tan colour discolouration of vascular bundles.
Etiology: Septate mycelia inter and intra-cellular haustoria ,produces V shaped conidiophore on which round shaped small conidia are borne
- Vegetative structures: Sclerotial bodies
- Sexual spores: Ascospore
- Asexual spore: Micro and macro conidia
- Primary Sources of Inoculum : Dormant mycelia
- Secondary Sources of Inoculum : Soil and air borne micro and macro- conidia
Epidemiology
- Temp. 30-32oc, RH-90-92%, alkaline pH, Black Clay soil, low moisture, susceptible host
Life cycle
- Perithecium is a sexual fruiting body.
- It has ascus, when it matures it produces ascospores.
- These ascospores flight on the air and chance factor lands on the host.
- It enters the host through natural openings.
- The host shows wilt symptoms & produces micro and macro conidia & again lands on the host like asexual life cycle continues.
- If conditions are adverse like high or low Temperature, high or low Relative humidity it starts sexual life cycle.
Management
- Collect and burn affected plant parts.
- Use soils free from nematode.
- Crop rotation with non host crops.
- Application of biological agents Trichoderma spp.
- Soil drenching with carbendazim 0.1%
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Last modified: Thursday, 1 March 2012, 1:18 PM