Studies on Epidemiology and Control of Chickpea Wilt Cased By Jusarium Oxysporum in Plateau Region of Bihar
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Date
1995
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Birsa Agricultural University, Ranchi
Abstract
Wilt of chickpea caused by Fusarium oxysporum f.sp. ciceri is one of the most important disease in chickpea growing area and it is responsible for heavy reduction in plant stand and yield.
The affected seedlings show dropping of the leaves and paler colour than the healthy seedlings. They collapse and lie flat on the ground. The initial symptom of adult plants is dropping of petiols and rachis along with leaflets. Within 2 to 3 days dropping is seen on the entire plant. There is a show fading of the green colour and the plant looks dull green. Gradually all leaves turn yellow and straw-coloured. The disease plants are easily pulled out from the soil than the healthy ones. The affected plant show internal discolouration of the pith and xylem.
The macro and micro-conidia and chlamydospores are produced by the pathogen in the host as well as in culture. Isolated fungus proved its pathogenicity during Koch's postulates test. Patato dextrose agar and Richards liquid medium proved to be the best. for excellent growth and sporulation of the pathogen.
h The fungus could utilize all the tested carbon compounds for its growth and sporulation but mannitol proved to be the best. Among nitrogen sources, sodium nitrate wis excellent for growth and sporulation. Amongst the micro nutrients, the mixture of zinc. with iron was fungus in-vitro. found excellent for growth and sporulation of the
The pathogen had a wide host range and was associated internally with the roots of pigeonpea, blackgram, greengram, linseed, lentil, pea, mustard and common weed present in chickpea field
without expressing wilt symptoms, but not from sorghum, soybean, wheat and mize.
The earlier wilting caused more loss than late wilting. The per cent loss in seed weight per plant at flower and podding stage, full podding stage and pre harvest stage were 95.81, 72.32. 39.70 per cent respectively.
Out of 149 entries screened, only six entries viz: H 82-2, GL-87123, GL-90104, GNG-920, PCS-2 and RSG-538 were proved resistant to wilt. Late and deep sowing, soil solarization and intercrops with wheat, lentil, safflower and linseed reduced disease. incidence but plant population and different levels of fertilizers could not. reduce the disease incidence. All the tested oil cakes @ 25 q/ha increased the germination percentage of seeds, while neem cake not only increased the germination but also reduced the incidence of wilt.
In biological control, Trichoderma viride and Gliocladium virens showed strong antagonestic action against pathogen in-vitro as well as in-vivo. They reduced the incidence of wilt when used as seed treatment and soil drenching. Thiram and Bavistin proved to be the most suitable fungicide in-vitro and minimized the disease incidence and increased the grain yield under field conditions. but maximum economic turn-over of Rs. 5.27 from an investment of Rs. 1.00 was obtained from two times drenching with Blitox-50 (0.3 per cent) during fungicidal control of the chickpea wilt.