3.1.4
CULTURAL PRACTICES FOR CONTROL OF ROOT ROT OF SUGAR BEET AND EFFECT OF TEMPERATURE ON SURVIVAL OF SCLEROTIA OF SCLEROTIUM ROLFSII

BHIM SEN SHARMA and VN PATHAK

Agricultural Research Station, Rajasthan Agricultural University, Durgapura, Jaipur, Rajasthan, India

Background and objective
Root rot of sugar beet, Beta vulgaris, incited by Sclerotium rolfsii, is an important disease in sugar beet-producing areas in India and abroad [1-3]. The effect of different cultural practices and certain physical strategies on disease incidence was studied.

Materials and methods
The effects of different sowing dates (31 Oct, 10, 20, 30 Nov, 10 Dec), method of sowing (ridge and flat), summer ploughing and trash burning on the incidence of sugar beet root rot and on root yield were studied under field conditions.

Results and conclusions
The crop sown on 31 Oct showed the lowest disease incidence (6.7 and 7.4%) together with highest root yield (7.9 and 8.7 kg/plot). Disease progressed as the sowing was delayed. Ridge sowing reduced the incidence of disease by 17.7-21.2% and increased the yield by 23.6-25.7% as compared to flat sowing. Three summer ploughings and dried trash burning at 100 kg/plot (2x2 m) provided above 90% control of the disease along with 42-62% higher yield over the check at two locations. Trash burning was superior to summer ploughing. Sclerotial viability declined sharply above 45C and was completely lost when exposed to 65C for 10 min.

References
1. Harris L, Allmaras PR, Rhoades HR, Pumphrey FV, 1956. J. American Soc. Sugarbeet Tech. 9, 226-232.
2. Jackson EB, Carasso FM, 1968. J. American Soc. Sugarbeet Tech. 15, 528-537.
3. Misra AP, Haque SQ, 1962. Proc. Indian Acad. 56, 157-168.