Leaf spot
Causal organism : Curvularia lunata
Symptoms
- Small unclear brown spots scattered over the leaf lamina.
- The minute spot increase in size, forming big spherical or irregular patches.
- Severe in neglected crops
Epidemiology
- Nutritionally poor soil,
- Temp 28-32o C,
- RH 85-90per cent,
- Cloudy weather
- Susceptible host.
- Primary Sources of Inoculum : Dormant mycelia
- Secondary Sources of Inoculum : Air borne conidia
Etiology
- Septate mycelia, inter and intracellular haustoria. any one of the conidia or conidiophore is coloured
- Asexual spores-Air borne conidia on conidiophore,
- Sexual spores- Ascospores
- Vegetative structure is dormant mycelia.
Life cycle
- Affected plant parts having Pseudothecium as primary source of inoculum.
- Favourable climate it will release ascospores they flight on to air and land on to the host, causes infection and causes leaf spot of senna.
- In the affected host conidia are present , they produces conidiophore and cause infection by flight asexually.
- During adverse climatic conditions the fungi switched on to sexual reproduction where gametangial contact followed by plasmogamy, karyogamy, mitosis and meiosis takes place by this inoculum is reproduced
Management
- Collect and destroy affected plant parts
- Increased nutritional status
- Reduce plant population
- Biological agent Trichoderma spp.
- Mancozeb 0.25 % as aerial spray
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Last modified: Thursday, 1 March 2012, 12:36 PM