Wilt of Castor caused by Fusarium oxysporum f. sp. ricini: Detection and Pathogenecity in Castor ( Ricinus Communis L) Seed

Nagaraja Nagaraja, M. Krishnappa


he present investigation was undertaken with the
main objective to determine detection on seed borne Fusarium
oxysporum f.sp. ricini and its Pathogenicity were conducted at
Department of Applied Botany, PlantPathology laboratory,
Kuvempu University, Jnanasahyadri, Shankaraghatta,
Shivamogga, Karnataka. Castor is one of the important non
edible oilseed crops in India. Wilt of castor is caused by F.
oxysporum f. sp. ricini. The objective of this work were to
estimate the incidence of F. oxysporum f. sp. ricini in castor
seed using different seed health test methods. A total 69 samples
were collected from retail shops, APMC markets, fields and
farmers of different agro-climatic regions of Karnataka during-
2011. The collected samples, ten samples show a higher
incidence of F. oxysporum f. sp. ricini and other fungi, were
selected for PDA, Water agar and 2,4-D methods. The incidence
of seed infection was 19.7 percent on a selective medium for
standard blotter method (SBM), Potato dextrose agar medium
13.1 percent (PDA), Water agar medium 8.9 percent and 2,4-D
11.0 percent (2, Dichloro phenoxy acetic acid) methods
respectively. Determine the rate of pathogenicity under green
house conditions. F. oxysporum f. sp. ricini showed the
symptoms of wilts were observed in 1-10 percent wilts in one,
10-30 percent in two month seedlings and 30-60 percent wilts in
three month old plants, no wilts observed in water treatment
plants. Among the sample collected field samples show a higher
incidence of F. oxysporum f. sp. ricini. The seed health test
methods, SBM is most superior for isolating the F. oxysporum f.
sp. ricini, pathogenic and saprophytic fungi. The importance of
infected seed and its pathogenicity were discussed. F. oxysporum
f. sp. ricini is a causal agent of wilt disease in castor crop.

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